/usr/share/perl5/HTML/Template.pm

package HTML::Template;

$HTML::Template::VERSION = '2.10';

=head1 NAME

HTML::Template - Perl module to use HTML-like templating language

=head1 SYNOPSIS

First you make a template - this is just a normal HTML file with a few
extra tags, the simplest being C<< <TMPL_VAR> >>

For example, test.tmpl:

    <html>
    <head><title>Test Template</title></head>
    <body>
    My Home Directory is <TMPL_VAR NAME=HOME>
    <p>
    My Path is set to <TMPL_VAR NAME=PATH>
    </body>
    </html>

Now you can use it in a small CGI program:

    #!/usr/bin/perl -w
    use HTML::Template;

    # open the html template
    my $template = HTML::Template->new(filename => 'test.tmpl');

    # fill in some parameters
    $template->param(HOME => $ENV{HOME});
    $template->param(PATH => $ENV{PATH});

    # send the obligatory Content-Type and print the template output
    print "Content-Type: text/html\n\n", $template->output;

If all is well in the universe this should show something like this in
your browser when visiting the CGI:

    My Home Directory is /home/some/directory
    My Path is set to /bin;/usr/bin

=head1 DESCRIPTION

This module attempts to make using HTML templates simple and natural.
It extends standard HTML with a few new HTML-esque tags - C<< <TMPL_VAR> >> 
C<< <TMPL_LOOP> >>, C<< <TMPL_INCLUDE> >>, C<< <TMPL_IF> >>, C<< <TMPL_ELSE> >> 
and C<< <TMPL_UNLESS> >>.  The file written with HTML and these new tags
is called a template.  It is usually saved separate from your script -
possibly even created by someone else!  Using this module you fill in the
values for the variables, loops and branches declared in the template.
This allows you to separate design - the HTML - from the data, which
you generate in the Perl script.

This module is licensed under the same terms as Perl. See the LICENSE
section below for more details.

=head1 TUTORIAL

If you're new to HTML::Template, I suggest you start with the
introductory article available on Perl Monks:

    http://www.perlmonks.org/?node_id=65642

=head1 FAQ

Please see L<HTML::Template::FAQ>

=head1 MOTIVATION

It is true that there are a number of packages out there to do HTML
templates.  On the one hand you have things like L<HTML::Embperl> which
allows you freely mix Perl with HTML.  On the other hand lie home-grown
variable substitution solutions.  Hopefully the module can find a place
between the two.

One advantage of this module over a full L<HTML::Embperl>-esque solution
is that it enforces an important divide - design and programming.
By limiting the programmer to just using simple variables and loops
in the HTML, the template remains accessible to designers and other
non-perl people.  The use of HTML-esque syntax goes further to make the
format understandable to others.  In the future this similarity could be
used to extend existing HTML editors/analyzers to support HTML::Template.

An advantage of this module over home-grown tag-replacement schemes is
the support for loops.  In my work I am often called on to produce
tables of data in html.  Producing them using simplistic HTML
templates results in programs containing lots of HTML since the HTML
itself cannot represent loops.  The introduction of loop statements in
the HTML simplifies this situation considerably.  The designer can
layout a single row and the programmer can fill it in as many times as
necessary - all they must agree on is the parameter names.

For all that, I think the best thing about this module is that it does
just one thing and it does it quickly and carefully.  It doesn't try
to replace Perl and HTML, it just augments them to interact a little
better.  And it's pretty fast.

=head1 THE TAGS

=head2 TMPL_VAR

    <TMPL_VAR NAME="PARAMETER_NAME">

The C<< <TMPL_VAR> >> tag is very simple.  For each C<< <TMPL_VAR> >>
tag in the template you call:

    $template->param(PARAMETER_NAME => "VALUE") 

When the template is output the C<< <TMPL_VAR>  >> is replaced with the
VALUE text you specified.  If you don't set a parameter it just gets
skipped in the output.

You can also specify the value of the parameter as a code reference in order
to have "lazy" variables. These sub routines will only be referenced if the
variables are used. See L<LAZY VALUES> for more information.

=head3 Attributes

The following "attributes" can also be specified in template var tags:

=over

=item * escape

This allows you to escape the value before it's put into the output. Th

This is useful when you want to use a TMPL_VAR in a context where those characters would
cause trouble. For example:

   <input name=param type=text value="<TMPL_VAR PARAM>">

If you called C<param()> with a value like C<sam"my> you'll get in trouble
with HTML's idea of a double-quote.  On the other hand, if you use
C<escape=html>, like this:

   <input name=param type=text value="<TMPL_VAR PARAM ESCAPE=HTML>">

You'll get what you wanted no matter what value happens to be passed
in for param.

The following escape values are supported:

=over

=item * html

Replaces the following characters with their HTML entity equivalent:
C<&>, C<">, C<'>, C<< < >>, C<< > >>

=item * js

Escapes (with a backslash) the following characters: C<\>, C<'>, C<">,
C<\n>, C<\r>

=item * url

URL escapes any ASCII characters except for letters, numbers, C<_>, C<.> and C<->.

=item * none 

Performs no escaping. This is the default, but it's useful to be able to explicitly
turn off escaping if you are using the C<default_escape> option.

=back

=item * default

With this attribute you can assign a default value to a variable.
For example, this will output "the devil gave me a taco" if the C<who>
variable is not set.

    <TMPL_VAR WHO DEFAULT="the devil"> gave me a taco.

=back

=head2 TMPL_LOOP

    <TMPL_LOOP NAME="LOOP_NAME"> ... </TMPL_LOOP>

The C<< <TMPL_LOOP> >> tag is a bit more complicated than C<< <TMPL_VAR> >>.  
The C<< <TMPL_LOOP> >> tag allows you to delimit a section of text and
give it a name.  Inside this named loop you place C<< <TMPL_VAR> >>s.
Now you pass to C<param()> a list (an array ref) of parameter assignments
(hash refs) for this loop.  The loop iterates over the list and produces
output from the text block for each pass.  Unset parameters are skipped.
Here's an example:

In the template:

   <TMPL_LOOP NAME=EMPLOYEE_INFO>
      Name: <TMPL_VAR NAME=NAME> <br>
      Job:  <TMPL_VAR NAME=JOB>  <p>
   </TMPL_LOOP>

In your Perl code:

    $template->param(
        EMPLOYEE_INFO => [{name => 'Sam', job => 'programmer'}, {name => 'Steve', job => 'soda jerk'}]
    );
    print $template->output();
  
The output is:

    Name: Sam
    Job: programmer

    Name: Steve
    Job: soda jerk

As you can see above the C<< <TMPL_LOOP> >> takes a list of variable
assignments and then iterates over the loop body producing output.

Often you'll want to generate a C<< <TMPL_LOOP> >>'s contents
programmatically.  Here's an example of how this can be done (many other
ways are possible!):

    # a couple of arrays of data to put in a loop:
    my @words     = qw(I Am Cool);
    my @numbers   = qw(1 2 3);
    my @loop_data = ();              # initialize an array to hold your loop

    while (@words and @numbers) {
        my %row_data;      # get a fresh hash for the row data

        # fill in this row
        $row_data{WORD}   = shift @words;
        $row_data{NUMBER} = shift @numbers;

        # the crucial step - push a reference to this row into the loop!
        push(@loop_data, \%row_data);
    }

    # finally, assign the loop data to the loop param, again with a reference:
    $template->param(THIS_LOOP => \@loop_data);

The above example would work with a template like:

    <TMPL_LOOP NAME="THIS_LOOP">
      Word: <TMPL_VAR NAME="WORD">     
      Number: <TMPL_VAR NAME="NUMBER">
 
    </TMPL_LOOP>

It would produce output like:

    Word: I
    Number: 1

    Word: Am
    Number: 2

    Word: Cool
    Number: 3

C<< <TMPL_LOOP> >>s within C<< <TMPL_LOOP> >>s are fine and work as you
would expect.  If the syntax for the C<param()> call has you stumped,
here's an example of a param call with one nested loop:

    $template->param(
        LOOP => [
            {
                name      => 'Bobby',
                nicknames => [{name => 'the big bad wolf'}, {name => 'He-Man'}],
            },
        ],
    );

Basically, each C<< <TMPL_LOOP> >> gets an array reference.  Inside the
array are any number of hash references.  These hashes contain the
name=>value pairs for a single pass over the loop template.

Inside a C<< <TMPL_LOOP> >>, the only variables that are usable are the
ones from the C<< <TMPL_LOOP> >>.  The variables in the outer blocks
are not visible within a template loop.  For the computer-science geeks
among you, a C<< <TMPL_LOOP> >> introduces a new scope much like a perl
subroutine call.  If you want your variables to be global you can use
C<global_vars> option to C<new()> described below.

=head2 TMPL_INCLUDE

    <TMPL_INCLUDE NAME="filename.tmpl">

This tag includes a template directly into the current template at
the point where the tag is found.  The included template contents are
used exactly as if its contents were physically included in the master
template.

The file specified can be an absolute path (beginning with a '/' under
Unix, for example).  If it isn't absolute, the path to the enclosing
file is tried first.  After that the path in the environment variable
C<HTML_TEMPLATE_ROOT> is tried, if it exists.  Next, the "path" option
is consulted, first as-is and then with C<HTML_TEMPLATE_ROOT> prepended
if available.  As a final attempt, the filename is passed to C<open()>
directly.  See below for more information on C<HTML_TEMPLATE_ROOT>
and the C<path> option to C<new()>.

As a protection against infinitely recursive includes, an arbitrary
limit of 10 levels deep is imposed.  You can alter this limit with the
C<max_includes> option.  See the entry for the C<max_includes> option
below for more details.

=head2 TMPL_IF

    <TMPL_IF NAME="PARAMETER_NAME"> ... </TMPL_IF>

The C<< <TMPL_IF> >> tag allows you to include or not include a block
of the template based on the value of a given parameter name.  If the
parameter is given a value that is true for Perl - like '1' - then the
block is included in the output.  If it is not defined, or given a false
value - like '0' - then it is skipped.  The parameters are specified
the same way as with C<< <TMPL_VAR> >>.

Example Template:

    <TMPL_IF NAME="BOOL">
      Some text that only gets displayed if BOOL is true!
    </TMPL_IF>

Now if you call C<< $template->param(BOOL => 1) >> then the above block
will be included by output.

C<< <TMPL_IF> </TMPL_IF> >> blocks can include any valid HTML::Template
construct - C<VAR>s and C<LOOP>s and other C<IF>/C<ELSE> blocks.  Note,
however, that intersecting a C<< <TMPL_IF> >> and a C<< <TMPL_LOOP> >>
is invalid.

    Not going to work:
    <TMPL_IF BOOL>
      <TMPL_LOOP SOME_LOOP>
    </TMPL_IF>
      </TMPL_LOOP>

If the name of a C<< <TMPL_LOOP> >> is used in a C<< <TMPL_IF> >>,
the C<IF> block will output if the loop has at least one row.  Example:

    <TMPL_IF LOOP_ONE>
      This will output if the loop is not empty.
    </TMPL_IF>

    <TMPL_LOOP LOOP_ONE>
      ....
    </TMPL_LOOP>

WARNING: Much of the benefit of HTML::Template is in decoupling your
Perl and HTML.  If you introduce numerous cases where you have
C<TMPL_IF>s and matching Perl C<if>s, you will create a maintenance
problem in keeping the two synchronized.  I suggest you adopt the
practice of only using C<TMPL_IF> if you can do so without requiring a
matching C<if> in your Perl code.

=head2 TMPL_ELSE

    <TMPL_IF NAME="PARAMETER_NAME"> ... <TMPL_ELSE> ... </TMPL_IF>

You can include an alternate block in your C<< <TMPL_IF> >> block by using
C<< <TMPL_ELSE> >>.  NOTE: You still end the block with C<< </TMPL_IF> >>, 
not C<< </TMPL_ELSE> >>!
 
   Example:
    <TMPL_IF BOOL>
      Some text that is included only if BOOL is true
    <TMPL_ELSE>
      Some text that is included only if BOOL is false
    </TMPL_IF>

=head2 TMPL_UNLESS

    <TMPL_UNLESS NAME="PARAMETER_NAME"> ... </TMPL_UNLESS>

This tag is the opposite of C<< <TMPL_IF> >>.  The block is output if the
C<PARAMETER_NAME> is set false or not defined.  You can use
C<< <TMPL_ELSE> >> with C<< <TMPL_UNLESS> >> just as you can with C<< <TMPL_IF> >>.

    Example:
    <TMPL_UNLESS BOOL>
      Some text that is output only if BOOL is FALSE.
    <TMPL_ELSE>
      Some text that is output only if BOOL is TRUE.
    </TMPL_UNLESS>

If the name of a C<< <TMPL_LOOP> >> is used in a C<< <TMPL_UNLESS> >>,
the C<< <UNLESS> >> block output if the loop has zero rows.

    <TMPL_UNLESS LOOP_ONE>
      This will output if the loop is empty.
    </TMPL_UNLESS>

    <TMPL_LOOP LOOP_ONE>
      ....
    </TMPL_LOOP>

=cut

=head2 NOTES

HTML::Template's tags are meant to mimic normal HTML tags.  However,
they are allowed to "break the rules".  Something like:

    <img src="<TMPL_VAR IMAGE_SRC>">

is not really valid HTML, but it is a perfectly valid use and will work
as planned.

The C<NAME=> in the tag is optional, although for extensibility's sake I
recommend using it.  Example - C<< <TMPL_LOOP LOOP_NAME> >> is acceptable.

If you're a fanatic about valid HTML and would like your templates
to conform to valid HTML syntax, you may optionally type template tags
in the form of HTML comments. This may be of use to HTML authors who
would like to validate their templates' HTML syntax prior to
HTML::Template processing, or who use DTD-savvy editing tools.

  <!-- TMPL_VAR NAME=PARAM1 -->

In order to realize a dramatic savings in bandwidth, the standard
(non-comment) tags will be used throughout this documentation.

=head1 METHODS

=head2 new

Call C<new()> to create a new Template object:

    my $template = HTML::Template->new(
        filename => 'file.tmpl',
        option   => 'value',
    );

You must call C<new()> with at least one C<name => value> pair specifying how
to access the template text.  You can use C<< filename => 'file.tmpl' >> 
to specify a filename to be opened as the template.  Alternately you can
use:

    my $t = HTML::Template->new(
        scalarref => $ref_to_template_text,
        option    => 'value',
    );

and

    my $t = HTML::Template->new(
        arrayref => $ref_to_array_of_lines,
        option   => 'value',
    );

These initialize the template from in-memory resources.  In almost every
case you'll want to use the filename parameter.  If you're worried about
all the disk access from reading a template file just use mod_perl and
the cache option detailed below.

You can also read the template from an already opened filehandle, either
traditionally as a glob or as a L<FileHandle>:

    my $t = HTML::Template->new(filehandle => *FH, option => 'value');

The four C<new()> calling methods can also be accessed as below, if you
prefer.

    my $t = HTML::Template->new_file('file.tmpl', option => 'value');

    my $t = HTML::Template->new_scalar_ref($ref_to_template_text, option => 'value');

    my $t = HTML::Template->new_array_ref($ref_to_array_of_lines, option => 'value');

    my $t = HTML::Template->new_filehandle($fh, option => 'value');

And as a final option, for those that might prefer it, you can call new as:

    my $t = HTML::Template->new(
        type   => 'filename',
        source => 'file.tmpl',
    );

Which works for all three of the source types.

If the environment variable C<HTML_TEMPLATE_ROOT> is set and your
filename doesn't begin with "/", then the path will be relative to the
value of c<HTML_TEMPLATE_ROOT>.  

B<Example> - if the environment variable C<HTML_TEMPLATE_ROOT> is set to
F</home/sam> and I call C<< HTML::Template->new() >> with filename set
to "sam.tmpl", HTML::Template will try to open F</home/sam/sam.tmpl> to
access the template file.  You can also affect the search path for files
with the C<path> option to C<new()> - see below for more information.

You can modify the Template object's behavior with C<new()>. The options
are available:

=head3 Error Detection Options

=over

=item * die_on_bad_params

If set to 0 the module will let you call:

    $template->param(param_name => 'value')

even if 'param_name' doesn't exist in the template body.  Defaults to 1.

=item * force_untaint 

If set to 1 the module will not allow you to set unescaped parameters
with tainted values. If set to 2 you will have to untaint all
parameters, including ones with the escape attribute.  This option
makes sure you untaint everything so you don't accidentally introduce
e.g. cross-site-scripting (XSS) vulnerabilities. Requires taint
mode. Defaults to 0.

=item *

strict - if set to 0 the module will allow things that look like they
might be TMPL_* tags to get by without dieing.  Example:

    <TMPL_HUH NAME=ZUH>

Would normally cause an error, but if you call new with C<< strict => 0 >> 
HTML::Template will ignore it.  Defaults to 1.

=item * vanguard_compatibility_mode 

If set to 1 the module will expect to see C<< <TMPL_VAR> >>s that
look like C<%NAME%> in addition to the standard syntax.  Also sets
C<die_on_bad_params => 0>.  If you're not at Vanguard Media trying to
use an old format template don't worry about this one.  Defaults to 0.

=back

=head3 Caching Options

=over

=item * cache

If set to 1 the module will cache in memory the parsed templates based
on the filename parameter, the modification date of the file and the
options passed to C<new()>. This only applies to templates opened with
the filename parameter specified, not scalarref or arrayref templates.
Caching also looks at the modification times of any files included using
C<< <TMPL_INCLUDE> >> tags, but again, only if the template is opened
with filename parameter.

This is mainly of use in a persistent environment like Apache/mod_perl.
It has absolutely no benefit in a normal CGI environment since the script
is unloaded from memory after every request.  For a cache that does work
for a non-persistent environment see the C<shared_cache> option below.

My simplistic testing shows that using cache yields a 90% performance
increase under mod_perl.  Cache defaults to 0.

=item * shared_cache

If set to 1 the module will store its cache in shared memory using the
L<IPC::SharedCache> module (available from CPAN).  The effect of this
will be to maintain a single shared copy of each parsed template for
all instances of HTML::Template on the same machine to use.  This can
be a significant reduction in memory usage in an environment with a
single machine but multiple servers.  As an example, on one of our
systems we use 4MB of template cache and maintain 25 httpd processes -
shared_cache results in saving almost 100MB!  Of course, some reduction
in speed versus normal caching is to be expected.  Another difference
between normal caching and shared_cache is that shared_cache will work
in a non-persistent environment (like normal CGI) - normal caching is
only useful in a persistent environment like Apache/mod_perl.

By default HTML::Template uses the IPC key 'TMPL' as a shared root
segment (0x4c504d54 in hex), but this can be changed by setting the
C<ipc_key> C<new()> parameter to another 4-character or integer key.
Other options can be used to affect the shared memory cache correspond
to L<IPC::SharedCache> options - C<ipc_mode>, C<ipc_segment_size> and
C<ipc_max_size>.  See L<IPC::SharedCache> for a description of how these
work - in most cases you shouldn't need to change them from the defaults.

For more information about the shared memory cache system used by
HTML::Template see L<IPC::SharedCache>.

=item * double_cache

If set to 1 the module will use a combination of C<shared_cache> and
normal cache mode for the best possible caching.  Of course, it also uses
the most memory of all the cache modes.  All the same ipc_* options that
work with C<shared_cache> apply to C<double_cache> as well. Defaults to 0.

=item * blind_cache

If set to 1 the module behaves exactly as with normal caching but does
not check to see if the file has changed on each request.  This option
should be used with caution, but could be of use on high-load servers.
My tests show C<blind_cache> performing only 1 to 2 percent faster than
cache under mod_perl.

B<NOTE>: Combining this option with shared_cache can result in stale
templates stuck permanently in shared memory!

=item * file_cache

If set to 1 the module will store its cache in a file using
the L<Storable> module.  It uses no additional memory, and my
simplistic testing shows that it yields a 50% performance advantage.
Like C<shared_cache>, it will work in a non-persistent environments
(like CGI). Default is 0.

If you set this option you must set the C<file_cache_dir> option. See
below for details.

B<NOTE>: L<Storable> uses C<flock()> to ensure safe access to cache
files.  Using C<file_cache> on a system or filesystem (like NFS) without
C<flock()> support is dangerous.

=item * file_cache_dir 

Sets the directory where the module will store the cache files if
C<file_cache> is enabled.  Your script will need write permissions to
this directory.  You'll also need to make sure the sufficient space is
available to store the cache files.

=item * file_cache_dir_mode

Sets the file mode for newly created C<file_cache> directories and
subdirectories.  Defaults to "0700" for security but this may be
inconvenient if you do not have access to the account running the
webserver.

=item * double_file_cache

If set to 1 the module will use a combination of C<file_cache> and
normal C<cache> mode for the best possible caching.  The file_cache_*
options that work with file_cache apply to C<double_file_cache> as well.
Defaults to 0.

=item * cache_lazy_vars

The option tells HTML::Template to cache the values returned from code references
used for C<TMPL_VAR>s. See L<LAZY VALUES> for details.

=item * cache_lazy_loops

The option tells HTML::Template to cache the values returned from code references
used for C<TMPL_LOOP>s. See L<LAZY VALUES> for details.

=back

=head3 Filesystem Options

=over

=item * path

You can set this variable with a list of paths to search for files
specified with the C<filename> option to C<new()> and for files included
with the C<< <TMPL_INCLUDE> >> tag.  This list is only consulted when the
filename is relative.  The C<HTML_TEMPLATE_ROOT> environment variable
is always tried first if it exists.  Also, if C<HTML_TEMPLATE_ROOT> is
set then an attempt will be made to prepend C<HTML_TEMPLATE_ROOT> onto
paths in the path array.  In the case of a C<< <TMPL_INCLUDE> >> file,
the path to the including file is also tried before path is consulted.

Example:

    my $template = HTML::Template->new(
        filename => 'file.tmpl',
        path     => ['/path/to/templates', '/alternate/path'],
    );

B<NOTE>: the paths in the path list must be expressed as UNIX paths,
separated by the forward-slash character ('/').

=item * search_path_on_include

If set to a true value the module will search from the top of the array
of paths specified by the path option on every C<< <TMPL_INCLUDE> >> and
use the first matching template found.  The normal behavior is to look
only in the current directory for a template to include.  Defaults to 0.

=item * utf8

Setting this to true tells HTML::Template to treat your template files as
UTF-8 encoded.  This will apply to any file's passed to C<new()> or any
included files. It won't do anything special to scalars templates passed
to C<new()> since you should be doing the encoding on those yourself.

    my $template = HTML::Template->new(
        filename => 'umlauts_are_awesome.tmpl',
        utf8     => 1,
    );

Most templates are either ASCII (the default) or UTF-8 encoded
Unicode. But if you need some other encoding other than these 2, look
at the C<open_mode> option.

B<NOTE>: The C<utf8> and C<open_mode> options cannot be used at the
same time.

=item * open_mode

You can set this option to an opening mode with which all template files
will be opened.

For example, if you want to use a template that is UTF-16 encoded unicode:

    my $template = HTML::Template->new(
        filename  => 'file.tmpl',
        open_mode => '<:encoding(UTF-16)',
    );

That way you can force a different encoding (than the default ASCII
or UTF-8), CR/LF properties etc. on the template files. See L<PerlIO>
for details.

B<NOTE>: this only works in perl 5.7.1 and above. 

B<NOTE>: you have to supply an opening mode that actually permits
reading from the file handle.

B<NOTE>: The C<utf8> and C<open_mode> options cannot be used at the
same time.

=back

=head3 Debugging Options

=over

=item * debug

If set to 1 the module will write random debugging information to STDERR.
Defaults to 0.

=item * stack_debug

If set to 1 the module will use Data::Dumper to print out the contents
of the parse_stack to STDERR.  Defaults to 0.

=item * cache_debug

If set to 1 the module will send information on cache loads, hits and
misses to STDERR.  Defaults to 0.

=item * shared_cache_debug

If set to 1 the module will turn on the debug option in
L<IPC::SharedCache>. Defaults to 0.

=item * memory_debug

If set to 1 the module will send information on cache memory usage
to STDERR.  Requires the L<GTop> module.  Defaults to 0.

=back

=head3 Miscellaneous Options

=over

=item * associate

This option allows you to inherit the parameter values
from other objects.  The only requirement for the other object is that
it have a C<param()> method that works like HTML::Template's C<param()>.  A
good candidate would be a L<CGI> query object. Example:

    my $query    = CGI->new;
    my $template = HTML::Template->new(
        filename  => 'template.tmpl',
        associate => $query,
    );

Now, C<< $template->output() >> will act as though

    $template->param(form_field => $cgi->param('form_field'));

had been specified for each key/value pair that would be provided by the
C<< $cgi->param() >> method.  Parameters you set directly take precedence
over associated parameters.

You can specify multiple objects to associate by passing an anonymous
array to the associate option.  They are searched for parameters in the
order they appear:

    my $template = HTML::Template->new(
        filename  => 'template.tmpl',
        associate => [$query, $other_obj],
    );

B<NOTE>: The parameter names are matched in a case-insensitive manner.
If you have two parameters in a CGI object like 'NAME' and 'Name' one
will be chosen randomly by associate.  This behavior can be changed by
the C<case_sensitive> option.

=item * case_sensitive

Setting this option to true causes HTML::Template to treat template
variable names case-sensitively.  The following example would only set
one parameter without the C<case_sensitive> option:

    my $template = HTML::Template->new(
        filename       => 'template.tmpl',
        case_sensitive => 1
    );
    $template->param(
        FieldA => 'foo',
        fIELDa => 'bar',
    );

This option defaults to off.

B<NOTE>: with C<case_sensitive> and C<loop_context_vars> the special
loop variables are available in lower-case only.

=item * loop_context_vars

When this parameter is set to true (it is false by default) extra variables
that depend on the loop's context are made available inside a loop. These are:

=over

=item * __first__

Value that is true for the first iteration of the loop and false every other time.

=item * __last__

Value that is true for the last iteration of the loop and false every other time.

=item * __inner__

Value that is true for the every iteration of the loop except for the first and last.

=item * __outer__

Value that is true for the first and last iterations of the loop.

=item * __odd__

Value that is true for the every odd iteration of the loop.

=item * __even__

Value that is true for the every event iteration of the loop.

=item * __counter__

An integer (starting from 1) who's value increments for each iteraction of the loop

=item * __index__

An integer (starting from 0) who's value increments for each iteraction of the loop

=back

Just like any other C<TMPL_VAR>s these variables can be used in 
C<< <TMPL_IF> >>, C<< <TMPL_UNLESS> >> and C<< <TMPL_ELSE> >> to control
how a loop is output.

Example:

    <TMPL_LOOP NAME="FOO">
      <TMPL_IF NAME="__first__">
        This only outputs on the first pass.
      </TMPL_IF>

      <TMPL_IF NAME="__odd__">
        This outputs every other pass, on the odd passes.
      </TMPL_IF>

      <TMPL_UNLESS NAME="__odd__">
        This outputs every other pass, on the even passes.
      </TMPL_UNLESS>

      <TMPL_IF NAME="__inner__">
        This outputs on passes that are neither first nor last.
      </TMPL_IF>

      This is pass number <TMPL_VAR NAME="__counter__">.

      <TMPL_IF NAME="__last__">
        This only outputs on the last pass.
      </TMPL_IF>
    </TMPL_LOOP>

One use of this feature is to provide a "separator" similar in effect
to the perl function C<join()>.  Example:

    <TMPL_LOOP FRUIT>
      <TMPL_IF __last__> and </TMPL_IF>
      <TMPL_VAR KIND><TMPL_UNLESS __last__>, <TMPL_ELSE>.</TMPL_UNLESS>
    </TMPL_LOOP>

Would output something like:

  Apples, Oranges, Brains, Toes, and Kiwi.

Given an appropriate C<param()> call, of course. B<NOTE>: A loop with only
a single pass will get both C<__first__> and C<__last__> set to true, but
not C<__inner__>.

=item * no_includes

Set this option to 1 to disallow the C<< <TMPL_INCLUDE> >> tag in the
template file.  This can be used to make opening untrusted templates
B<slightly> less dangerous.  Defaults to 0.

=item * max_includes

Set this variable to determine the maximum depth that includes can reach.
Set to 10 by default.  Including files to a depth greater than this
value causes an error message to be displayed.  Set to 0 to disable
this protection.

=item * die_on_missing_include

If true, then HTML::Template will die if it can't find a file for a
C<< <TMPL_INCLUDE> >>. This defaults to true.

=item * global_vars

Normally variables declared outside a loop are not available inside
a loop.  This option makes C<< <TMPL_VAR> >>s like global variables in
Perl - they have unlimited scope.  This option also affects C<< <TMPL_IF> >> 
and C<< <TMPL_UNLESS> >>.

Example:

    This is a normal variable: <TMPL_VAR NORMAL>.<P>

    <TMPL_LOOP NAME=FROOT_LOOP>
      Here it is inside the loop: <TMPL_VAR NORMAL><P>
    </TMPL_LOOP>

Normally this wouldn't work as expected, since C<< <TMPL_VAR NORMAL> >>'s 
value outside the loop is not available inside the loop.

The global_vars option also allows you to access the values of an
enclosing loop within an inner loop.  For example, in this loop the
inner loop will have access to the value of C<OUTER_VAR> in the correct
iteration:

    <TMPL_LOOP OUTER_LOOP>
      OUTER: <TMPL_VAR OUTER_VAR>
        <TMPL_LOOP INNER_LOOP>
           INNER: <TMPL_VAR INNER_VAR>
           INSIDE OUT: <TMPL_VAR OUTER_VAR>
        </TMPL_LOOP>
    </TMPL_LOOP>

One side-effect of C<global_vars> is that variables you set with
C<param()> that might otherwise be ignored when C<die_on_bad_params>
is off will stick around.  This is necessary to allow inner loops to
access values set for outer loops that don't directly use the value.

B<NOTE>: C<global_vars> is not C<global_loops> (which does not exist).
That means that loops you declare at one scope are not available
inside other loops even when C<global_vars> is on.

=item * filter

This option allows you to specify a filter for your template files.
A filter is a subroutine that will be called after HTML::Template reads
your template file but before it starts parsing template tags.

In the most simple usage, you simply assign a code reference to the
filter parameter.  This subroutine will receive a single argument -
a reference to a string containing the template file text.  Here is
an example that accepts templates with tags that look like 
C<!!!ZAP_VAR FOO!!!> and transforms them into HTML::Template tags:

    my $filter = sub {
        my $text_ref = shift;
        $$text_ref =~ s/!!!ZAP_(.*?)!!!/<TMPL_$1>/g;
    };

    # open zap.tmpl using the above filter
    my $template = HTML::Template->new(
        filename => 'zap.tmpl',
        filter   => $filter,
    );

More complicated usages are possible.  You can request that your
filter receieve the template text as an array of lines rather than
as a single scalar.  To do that you need to specify your filter using
a hash-ref.  In this form you specify the filter using the C<sub> key
and the desired argument format using the C<format> key.  The available
formats are C<scalar> and C<array>.  Using the C<array> format will
incur a performance penalty but may be more convenient in some situations.

    my $template = HTML::Template->new(
        filename => 'zap.tmpl',
        filter   => {
            sub    => $filter,
            format => 'array',
        }
    );

You may also have multiple filters.  This allows simple filters to be
combined for more elaborate functionality.  To do this you specify
an array of filters.  The filters are applied in the order they are
specified.

    my $template = HTML::Template->new(
        filename => 'zap.tmpl',
        filter   => [
            {
                sub    => \&decompress,
                format => 'scalar',
            },
            {
                sub    => \&remove_spaces,
                format => 'array',
            },
        ]
    );

The specified filters will be called for any C<TMPL_INCLUDE>ed files just
as they are for the main template file.

=item * default_escape

Set this parameter to a valid escape type (see the C<escape> option)
and HTML::Template will apply the specified escaping to all variables
unless they declare a different escape in the template.

=back

=cut

use integer;    # no floating point math so far!
use strict;     # and no funny business, either.

use Carp;                       # generate better errors with more context
use File::Spec;                 # generate paths that work on all platforms
use Digest::MD5 qw(md5_hex);    # generate cache keys
use Scalar::Util qw(tainted);

# define accessor constants used to improve readability of array
# accesses into "objects".  I used to use 'use constant' but that
# seems to cause occasional irritating warnings in older Perls.
package HTML::Template::LOOP;
sub TEMPLATE_HASH () { 0 }
sub PARAM_SET ()     { 1 }

package HTML::Template::COND;
sub VARIABLE ()           { 0 }
sub VARIABLE_TYPE ()      { 1 }
sub VARIABLE_TYPE_VAR ()  { 0 }
sub VARIABLE_TYPE_LOOP () { 1 }
sub JUMP_IF_TRUE ()       { 2 }
sub JUMP_ADDRESS ()       { 3 }
sub WHICH ()              { 4 }
sub UNCONDITIONAL_JUMP () { 5 }
sub IS_ELSE ()            { 6 }
sub WHICH_IF ()           { 0 }
sub WHICH_UNLESS ()       { 1 }

# back to the main package scope.
package HTML::Template;

# open a new template and return an object handle
sub new {
    my $pkg = shift;
    my $self;
    { my %hash; $self = bless(\%hash, $pkg); }

    # the options hash
    my $options = {};
    $self->{options} = $options;

    # set default parameters in options hash
    %$options = (
        debug                       => 0,
        stack_debug                 => 0,
        timing                      => 0,
        search_path_on_include      => 0,
        cache                       => 0,
        blind_cache                 => 0,
        file_cache                  => 0,
        file_cache_dir              => '',
        file_cache_dir_mode         => 0700,
        force_untaint               => 0,
        cache_debug                 => 0,
        shared_cache_debug          => 0,
        memory_debug                => 0,
        die_on_bad_params           => 1,
        vanguard_compatibility_mode => 0,
        associate                   => [],
        path                        => [],
        strict                      => 1,
        loop_context_vars           => 0,
        max_includes                => 10,
        shared_cache                => 0,
        double_cache                => 0,
        double_file_cache           => 0,
        ipc_key                     => 'TMPL',
        ipc_mode                    => 0666,
        ipc_segment_size            => 65536,
        ipc_max_size                => 0,
        global_vars                 => 0,
        no_includes                 => 0,
        case_sensitive              => 0,
        filter                      => [],
        open_mode                   => '',
        utf8                        => 0,
        cache_lazy_vars             => 0,
        cache_lazy_loops            => 0,
        die_on_missing_include      => 1,
    );

    # load in options supplied to new()
    $options = _load_supplied_options([@_], $options);

    # blind_cache = 1 implies cache = 1
    $options->{blind_cache} and $options->{cache} = 1;

    # shared_cache = 1 implies cache = 1
    $options->{shared_cache} and $options->{cache} = 1;

    # file_cache = 1 implies cache = 1
    $options->{file_cache} and $options->{cache} = 1;

    # double_cache is a combination of shared_cache and cache.
    $options->{double_cache} and $options->{cache}        = 1;
    $options->{double_cache} and $options->{shared_cache} = 1;

    # double_file_cache is a combination of file_cache and cache.
    $options->{double_file_cache} and $options->{cache}      = 1;
    $options->{double_file_cache} and $options->{file_cache} = 1;

    # vanguard_compatibility_mode implies die_on_bad_params = 0
    $options->{vanguard_compatibility_mode}
      and $options->{die_on_bad_params} = 0;

    # handle the "type", "source" parameter format (does anyone use it?)
    if (exists($options->{type})) {
        exists($options->{source})
          or croak("HTML::Template->new() called with 'type' parameter set, but no 'source'!");
        (
                 $options->{type} eq 'filename'
              or $options->{type} eq 'scalarref'
              or $options->{type} eq 'arrayref'
              or $options->{type} eq 'filehandle'
          )
          or croak("HTML::Template->new() : type parameter must be set to 'filename', 'arrayref', 'scalarref' or 'filehandle'!");

        $options->{$options->{type}} = $options->{source};
        delete $options->{type};
        delete $options->{source};
    }

    # make sure taint mode is on if force_untaint flag is set
    if ($options->{force_untaint}) {
        if ($] < 5.008000) {
            warn("HTML::Template->new() : 'force_untaint' option needs at least Perl 5.8.0!");
        } elsif (!${^TAINT}) {
            croak("HTML::Template->new() : 'force_untaint' option set but perl does not run in taint mode!");
        }
    }

    # associate should be an array of one element if it's not
    # already an array.
    if (ref($options->{associate}) ne 'ARRAY') {
        $options->{associate} = [$options->{associate}];
    }

    # path should be an array if it's not already
    if (ref($options->{path}) ne 'ARRAY') {
        $options->{path} = [$options->{path}];
    }

    # filter should be an array if it's not already
    if (ref($options->{filter}) ne 'ARRAY') {
        $options->{filter} = [$options->{filter}];
    }

    # make sure objects in associate area support param()
    foreach my $object (@{$options->{associate}}) {
        defined($object->can('param'))
          or croak("HTML::Template->new called with associate option, containing object of type "
              . ref($object)
              . " which lacks a param() method!");
    }

    # check for syntax errors:
    my $source_count = 0;
    exists($options->{filename})   and $source_count++;
    exists($options->{filehandle}) and $source_count++;
    exists($options->{arrayref})   and $source_count++;
    exists($options->{scalarref})  and $source_count++;
    if ($source_count != 1) {
        croak(
            "HTML::Template->new called with multiple (or no) template sources specified!  A valid call to new() has exactly one filename => 'file' OR exactly one scalarref => \\\$scalar OR exactly one arrayref => \\\@array OR exactly one filehandle => \*FH"
        );
    }

    # check that cache options are not used with non-cacheable templates
    croak "Cannot have caching when template source is not file"
      if grep { exists($options->{$_}) } qw( filehandle arrayref scalarref)
          and grep { $options->{$_} }
          qw( cache blind_cache file_cache shared_cache
          double_cache double_file_cache );

    # check that filenames aren't empty
    if (exists($options->{filename})) {
        croak("HTML::Template->new called with empty filename parameter!")
          unless length $options->{filename};
    }

    # do some memory debugging - this is best started as early as possible
    if ($options->{memory_debug}) {
        # memory_debug needs GTop
        eval { require GTop; };
        croak("Could not load GTop.  You must have GTop installed to use HTML::Template in memory_debug mode.  The error was: $@")
          if ($@);
        $self->{gtop}     = GTop->new();
        $self->{proc_mem} = $self->{gtop}->proc_mem($$);
        print STDERR "\n### HTML::Template Memory Debug ### START ", $self->{proc_mem}->size(), "\n";
    }

    if ($options->{file_cache}) {
        # make sure we have a file_cache_dir option
        croak("You must specify the file_cache_dir option if you want to use file_cache.")
          unless length $options->{file_cache_dir};

        # file_cache needs some extra modules loaded
        eval { require Storable; };
        croak(
            "Could not load Storable.  You must have Storable installed to use HTML::Template in file_cache mode.  The error was: $@"
        ) if ($@);
    }

    if ($options->{shared_cache}) {
        # shared_cache needs some extra modules loaded
        eval { require IPC::SharedCache; };
        croak(
            "Could not load IPC::SharedCache.  You must have IPC::SharedCache installed to use HTML::Template in shared_cache mode.  The error was: $@"
        ) if ($@);

        # initialize the shared cache
        my %cache;
        tie %cache, 'IPC::SharedCache',
          ipc_key           => $options->{ipc_key},
          load_callback     => [\&_load_shared_cache, $self],
          validate_callback => [\&_validate_shared_cache, $self],
          debug             => $options->{shared_cache_debug},
          ipc_mode          => $options->{ipc_mode},
          max_size          => $options->{ipc_max_size},
          ipc_segment_size  => $options->{ipc_segment_size};
        $self->{cache} = \%cache;
    }

    if ($options->{default_escape}) {
        $options->{default_escape} = uc $options->{default_escape};
        unless ($options->{default_escape} =~ /^(HTML|URL|JS)$/) {
            croak(
                "HTML::Template->new(): Invalid setting for default_escape - '$options->{default_escape}'.  Valid values are HTML, URL or JS."
            );
        }
    }

    # no 3 args form of open before perl 5.7.1
    if ($options->{open_mode} && $] < 5.007001) {
        croak("HTML::Template->new(): open_mode cannot be used in Perl < 5.7.1");
    }

    if($options->{utf8}) {
        croak("HTML::Template->new(): utf8 cannot be used in Perl < 5.7.1") if $] < 5.007001;
        croak("HTML::Template->new(): utf8 and open_mode cannot be used at the same time") if $options->{open_mode};

        # utf8 is just a short-cut for a common open_mode
        $options->{open_mode} = '<:encoding(utf8)';
    }

    print STDERR "### HTML::Template Memory Debug ### POST CACHE INIT ", $self->{proc_mem}->size(), "\n"
      if $options->{memory_debug};

    # initialize data structures
    $self->_init;

    print STDERR "### HTML::Template Memory Debug ### POST _INIT CALL ", $self->{proc_mem}->size(), "\n"
      if $options->{memory_debug};

    # drop the shared cache - leaving out this step results in the
    # template object evading garbage collection since the callbacks in
    # the shared cache tie hold references to $self!  This was not easy
    # to find, by the way.
    delete $self->{cache} if $options->{shared_cache};

    return $self;
}

sub _load_supplied_options {
    my $argsref = shift;
    my $options = shift;
    for (my $x = 0 ; $x < @{$argsref} ; $x += 2) {
        defined(${$argsref}[($x + 1)])
          or croak("HTML::Template->new() called with odd number of option parameters - should be of the form option => value");
        $options->{lc(${$argsref}[$x])} = ${$argsref}[($x + 1)];
    }
    return $options;
}

# an internally used new that receives its parse_stack and param_map as input
sub _new_from_loop {
    my $pkg = shift;
    my $self;
    { my %hash; $self = bless(\%hash, $pkg); }

    # the options hash
    my $options = {};
    $self->{options} = $options;

    # set default parameters in options hash - a subset of the options
    # valid in a normal new().  Since _new_from_loop never calls _init,
    # many options have no relevance.
    %$options = (
        debug             => 0,
        stack_debug       => 0,
        die_on_bad_params => 1,
        associate         => [],
        loop_context_vars => 0,
    );

    # load in options supplied to new()
    $options = _load_supplied_options([@_], $options);

    $self->{param_map}   = $options->{param_map};
    $self->{parse_stack} = $options->{parse_stack};
    delete($options->{param_map});
    delete($options->{parse_stack});

    return $self;
}

# a few shortcuts to new(), of possible use...
sub new_file {
    my $pkg = shift;
    return $pkg->new('filename', @_);
}

sub new_filehandle {
    my $pkg = shift;
    return $pkg->new('filehandle', @_);
}

sub new_array_ref {
    my $pkg = shift;
    return $pkg->new('arrayref', @_);
}

sub new_scalar_ref {
    my $pkg = shift;
    return $pkg->new('scalarref', @_);
}

# initializes all the object data structures, either from cache or by
# calling the appropriate routines.
sub _init {
    my $self    = shift;
    my $options = $self->{options};

    if ($options->{double_cache}) {
        # try the normal cache, return if we have it.
        $self->_fetch_from_cache();
        return if (defined $self->{param_map} and defined $self->{parse_stack});

        # try the shared cache
        $self->_fetch_from_shared_cache();

        # put it in the local cache if we got it.
        $self->_commit_to_cache()
          if (defined $self->{param_map} and defined $self->{parse_stack});
    } elsif ($options->{double_file_cache}) {
        # try the normal cache, return if we have it.
        $self->_fetch_from_cache();
        return if (defined $self->{param_map});

        # try the file cache
        $self->_fetch_from_file_cache();

        # put it in the local cache if we got it.
        $self->_commit_to_cache()
          if (defined $self->{param_map});
    } elsif ($options->{shared_cache}) {
        # try the shared cache
        $self->_fetch_from_shared_cache();
    } elsif ($options->{file_cache}) {
        # try the file cache
        $self->_fetch_from_file_cache();
    } elsif ($options->{cache}) {
        # try the normal cache
        $self->_fetch_from_cache();
    }

    # if we got a cache hit, return
    return if (defined $self->{param_map});

    # if we're here, then we didn't get a cached copy, so do a full
    # init.
    $self->_init_template();
    $self->_parse();

    # now that we have a full init, cache the structures if cacheing is
    # on.  shared cache is already cool.
    if ($options->{file_cache}) {
        $self->_commit_to_file_cache();
    }
    $self->_commit_to_cache()
      if ( ($options->{cache} and not $options->{shared_cache} and not $options->{file_cache})
        or ($options->{double_cache})
        or ($options->{double_file_cache}));
}

# Caching subroutines - they handle getting and validating cache
# records from either the in-memory or shared caches.

# handles the normal in memory cache
use vars qw( %CACHE );

sub _fetch_from_cache {
    my $self    = shift;
    my $options = $self->{options};

    # return if there's no file here
    my $filepath = $self->_find_file($options->{filename});
    return unless (defined($filepath));
    $options->{filepath} = $filepath;

    # return if there's no cache entry for this key
    my $key = $self->_cache_key();
    return unless exists($CACHE{$key});

    # validate the cache
    my $mtime = $self->_mtime($filepath);
    if (defined $mtime) {
        # return if the mtime doesn't match the cache
        if (defined($CACHE{$key}{mtime})
            and ($mtime != $CACHE{$key}{mtime}))
        {
            $options->{cache_debug}
              and print STDERR "CACHE MISS : $filepath : $mtime\n";
            return;
        }

        # if the template has includes, check each included file's mtime
        # and return if different
        if (exists($CACHE{$key}{included_mtimes})) {
            foreach my $filename (keys %{$CACHE{$key}{included_mtimes}}) {
                next
                  unless defined($CACHE{$key}{included_mtimes}{$filename});

                my $included_mtime = (stat($filename))[9];
                if ($included_mtime != $CACHE{$key}{included_mtimes}{$filename}) {
                    $options->{cache_debug}
                      and print STDERR
                      "### HTML::Template Cache Debug ### CACHE MISS : $filepath : INCLUDE $filename : $included_mtime\n";

                    return;
                }
            }
        }
    }

    # got a cache hit!

    $options->{cache_debug}
      and print STDERR "### HTML::Template Cache Debug ### CACHE HIT : $filepath => $key\n";

    $self->{param_map}   = $CACHE{$key}{param_map};
    $self->{parse_stack} = $CACHE{$key}{parse_stack};
    exists($CACHE{$key}{included_mtimes})
      and $self->{included_mtimes} = $CACHE{$key}{included_mtimes};

    # clear out values from param_map from last run
    $self->_normalize_options();
    $self->clear_params();
}

sub _commit_to_cache {
    my $self     = shift;
    my $options  = $self->{options};
    my $key      = $self->_cache_key();
    my $filepath = $options->{filepath};

    $options->{cache_debug}
      and print STDERR "### HTML::Template Cache Debug ### CACHE LOAD : $filepath => $key\n";

    $options->{blind_cache}
      or $CACHE{$key}{mtime} = $self->_mtime($filepath);
    $CACHE{$key}{param_map}   = $self->{param_map};
    $CACHE{$key}{parse_stack} = $self->{parse_stack};
    exists($self->{included_mtimes})
      and $CACHE{$key}{included_mtimes} = $self->{included_mtimes};
}

# create a cache key from a template object.  The cache key includes
# the full path to the template and options which affect template
# loading.
sub _cache_key {
    my $self    = shift;
    my $options = $self->{options};

    # assemble pieces of the key
    my @key = ($options->{filepath});
    push(@key, @{$options->{path}});

    push(@key, $options->{search_path_on_include} || 0);
    push(@key, $options->{loop_context_vars}      || 0);
    push(@key, $options->{global_vars}            || 0);
    push(@key, $options->{open_mode}              || 0);

    # compute the md5 and return it
    return md5_hex(@key);
}

# generates MD5 from filepath to determine filename for cache file
sub _get_cache_filename {
    my ($self, $filepath) = @_;

    # get a cache key
    $self->{options}{filepath} = $filepath;
    my $hash = $self->_cache_key();

    # ... and build a path out of it.  Using the first two charcters
    # gives us 255 buckets.  This means you can have 255,000 templates
    # in the cache before any one directory gets over a few thousand
    # files in it.  That's probably pretty good for this planet.  If not
    # then it should be configurable.
    if (wantarray) {
        return (substr($hash, 0, 2), substr($hash, 2));
    } else {
        return File::Spec->join($self->{options}{file_cache_dir}, substr($hash, 0, 2), substr($hash, 2));
    }
}

# handles the file cache
sub _fetch_from_file_cache {
    my $self    = shift;
    my $options = $self->{options};

    # return if there's no cache entry for this filename
    my $filepath = $self->_find_file($options->{filename});
    return unless defined $filepath;
    my $cache_filename = $self->_get_cache_filename($filepath);
    return unless -e $cache_filename;

    eval { $self->{record} = Storable::lock_retrieve($cache_filename); };
    croak("HTML::Template::new() - Problem reading cache file $cache_filename (file_cache => 1) : $@")
      if $@;
    croak("HTML::Template::new() - Problem reading cache file $cache_filename (file_cache => 1) : $!")
      unless defined $self->{record};

    ($self->{mtime}, $self->{included_mtimes}, $self->{param_map}, $self->{parse_stack}) = @{$self->{record}};

    $options->{filepath} = $filepath;

    # validate the cache
    my $mtime = $self->_mtime($filepath);
    if (defined $mtime) {
        # return if the mtime doesn't match the cache
        if (defined($self->{mtime})
            and ($mtime != $self->{mtime}))
        {
            $options->{cache_debug}
              and print STDERR "### HTML::Template Cache Debug ### FILE CACHE MISS : $filepath : $mtime\n";
            ($self->{mtime}, $self->{included_mtimes}, $self->{param_map}, $self->{parse_stack}) = (undef, undef, undef, undef);
            return;
        }

        # if the template has includes, check each included file's mtime
        # and return if different
        if (exists($self->{included_mtimes})) {
            foreach my $filename (keys %{$self->{included_mtimes}}) {
                next
                  unless defined($self->{included_mtimes}{$filename});

                my $included_mtime = (stat($filename))[9];
                if ($included_mtime != $self->{included_mtimes}{$filename}) {
                    $options->{cache_debug}
                      and print STDERR
                      "### HTML::Template Cache Debug ### FILE CACHE MISS : $filepath : INCLUDE $filename : $included_mtime\n";
                    ($self->{mtime}, $self->{included_mtimes}, $self->{param_map}, $self->{parse_stack}) =
                      (undef, undef, undef, undef);
                    return;
                }
            }
        }
    }

    # got a cache hit!
    $options->{cache_debug}
      and print STDERR "### HTML::Template Cache Debug ### FILE CACHE HIT : $filepath\n";

    # clear out values from param_map from last run
    $self->_normalize_options();
    $self->clear_params();
}

sub _commit_to_file_cache {
    my $self    = shift;
    my $options = $self->{options};

    my $filepath = $options->{filepath};
    if (not defined $filepath) {
        $filepath = $self->_find_file($options->{filename});
        confess("HTML::Template->new() : Cannot open included file $options->{filename} : file not found.")
          unless defined($filepath);
        $options->{filepath} = $filepath;
    }

    my ($cache_dir, $cache_file) = $self->_get_cache_filename($filepath);
    $cache_dir = File::Spec->join($options->{file_cache_dir}, $cache_dir);
    if (not -d $cache_dir) {
        if (not -d $options->{file_cache_dir}) {
            mkdir($options->{file_cache_dir}, $options->{file_cache_dir_mode})
              or croak("HTML::Template->new() : can't mkdir $options->{file_cache_dir} (file_cache => 1): $!");
        }
        mkdir($cache_dir, $options->{file_cache_dir_mode})
          or croak("HTML::Template->new() : can't mkdir $cache_dir (file_cache => 1): $!");
    }

    $options->{cache_debug}
      and print STDERR "### HTML::Template Cache Debug ### FILE CACHE LOAD : $options->{filepath}\n";

    my $result;
    eval {
        $result = Storable::lock_store([$self->{mtime}, $self->{included_mtimes}, $self->{param_map}, $self->{parse_stack}],
            scalar File::Spec->join($cache_dir, $cache_file));
    };
    croak("HTML::Template::new() - Problem writing cache file $cache_dir/$cache_file (file_cache => 1) : $@") if $@;
    croak("HTML::Template::new() - Problem writing cache file $cache_dir/$cache_file (file_cache => 1) : $!")
      unless defined $result;
}

# Shared cache routines.
sub _fetch_from_shared_cache {
    my $self    = shift;
    my $options = $self->{options};

    my $filepath = $self->_find_file($options->{filename});
    return unless defined $filepath;

    # fetch from the shared cache.
    $self->{record} = $self->{cache}{$filepath};

    ($self->{mtime}, $self->{included_mtimes}, $self->{param_map}, $self->{parse_stack}) = @{$self->{record}}
      if defined($self->{record});

    $options->{cache_debug}
      and defined($self->{record})
      and print STDERR "### HTML::Template Cache Debug ### CACHE HIT : $filepath\n";
    # clear out values from param_map from last run
    $self->_normalize_options(), $self->clear_params()
      if (defined($self->{record}));
    delete($self->{record});

    return $self;
}

sub _validate_shared_cache {
    my ($self, $filename, $record) = @_;
    my $options = $self->{options};

    $options->{shared_cache_debug}
      and print STDERR "### HTML::Template Cache Debug ### SHARED CACHE VALIDATE : $filename\n";

    return 1 if $options->{blind_cache};

    my ($c_mtime, $included_mtimes, $param_map, $parse_stack) = @$record;

    # if the modification time has changed return false
    my $mtime = $self->_mtime($filename);
    if (    defined $mtime
        and defined $c_mtime
        and $mtime != $c_mtime)
    {
        $options->{cache_debug}
          and print STDERR "### HTML::Template Cache Debug ### SHARED CACHE MISS : $filename : $mtime\n";
        return 0;
    }

    # if the template has includes, check each included file's mtime
    # and return false if different
    if (defined $mtime and defined $included_mtimes) {
        foreach my $fname (keys %$included_mtimes) {
            next unless defined($included_mtimes->{$fname});
            if ($included_mtimes->{$fname} != (stat($fname))[9]) {
                $options->{cache_debug}
                  and print STDERR "### HTML::Template Cache Debug ### SHARED CACHE MISS : $filename : INCLUDE $fname\n";
                return 0;
            }
        }
    }

    # all done - return true
    return 1;
}

sub _load_shared_cache {
    my ($self, $filename) = @_;
    my $options = $self->{options};
    my $cache   = $self->{cache};

    $self->_init_template();
    $self->_parse();

    $options->{cache_debug}
      and print STDERR "### HTML::Template Cache Debug ### SHARED CACHE LOAD : $options->{filepath}\n";

    print STDERR "### HTML::Template Memory Debug ### END CACHE LOAD ", $self->{proc_mem}->size(), "\n"
      if $options->{memory_debug};

    return [$self->{mtime}, $self->{included_mtimes}, $self->{param_map}, $self->{parse_stack}];
}

# utility function - given a filename performs documented search and
# returns a full path or undef if the file cannot be found.
sub _find_file {
    my ($self, $filename, $extra_path) = @_;
    my $options = $self->{options};
    my $filepath;

    # first check for a full path
    return File::Spec->canonpath($filename)
      if (File::Spec->file_name_is_absolute($filename) and (-e $filename));

    # try the extra_path if one was specified
    if (defined($extra_path)) {
        $extra_path->[$#{$extra_path}] = $filename;
        $filepath = File::Spec->canonpath(File::Spec->catfile(@$extra_path));
        return File::Spec->canonpath($filepath) if -e $filepath;
    }

    # try pre-prending HTML_Template_Root
    if (defined($ENV{HTML_TEMPLATE_ROOT})) {
        $filepath = File::Spec->catfile($ENV{HTML_TEMPLATE_ROOT}, $filename);
        return File::Spec->canonpath($filepath) if -e $filepath;
    }

    # try "path" option list..
    foreach my $path (@{$options->{path}}) {
        $filepath = File::Spec->catfile($path, $filename);
        return File::Spec->canonpath($filepath) if -e $filepath;
    }

    # try even a relative path from the current directory...
    return File::Spec->canonpath($filename) if -e $filename;

    # try "path" option list with HTML_TEMPLATE_ROOT prepended...
    if (defined($ENV{HTML_TEMPLATE_ROOT})) {
        foreach my $path (@{$options->{path}}) {
            $filepath = File::Spec->catfile($ENV{HTML_TEMPLATE_ROOT}, $path, $filename);
            return File::Spec->canonpath($filepath) if -e $filepath;
        }
    }

    return undef;
}

# utility function - computes the mtime for $filename
sub _mtime {
    my ($self, $filepath) = @_;
    my $options = $self->{options};

    return (undef) if ($options->{blind_cache});

    # make sure it still exists in the filesystem
    (-r $filepath)
      or Carp::confess("HTML::Template : template file $filepath does not exist or is unreadable.");

    # get the modification time
    return (stat(_))[9];
}

# utility function - enforces new() options across LOOPs that have
# come from a cache.  Otherwise they would have stale options hashes.
sub _normalize_options {
    my $self    = shift;
    my $options = $self->{options};

    my @pstacks = ($self->{parse_stack});
    while (@pstacks) {
        my $pstack = pop(@pstacks);
        foreach my $item (@$pstack) {
            next unless (ref($item) eq 'HTML::Template::LOOP');
            foreach my $template (values %{$item->[HTML::Template::LOOP::TEMPLATE_HASH]}) {
                # must be the same list as the call to _new_from_loop...
                $template->{options}{debug}              = $options->{debug};
                $template->{options}{stack_debug}        = $options->{stack_debug};
                $template->{options}{die_on_bad_params}  = $options->{die_on_bad_params};
                $template->{options}{case_sensitive}     = $options->{case_sensitive};
                $template->{options}{parent_global_vars} = $options->{parent_global_vars};

                push(@pstacks, $template->{parse_stack});
            }
        }
    }
}

# initialize the template buffer
sub _init_template {
    my $self    = shift;
    my $options = $self->{options};

    print STDERR "### HTML::Template Memory Debug ### START INIT_TEMPLATE ", $self->{proc_mem}->size(), "\n"
      if $options->{memory_debug};

    if (exists($options->{filename})) {
        my $filepath = $options->{filepath};
        if (not defined $filepath) {
            $filepath = $self->_find_file($options->{filename});
            confess("HTML::Template->new() : Cannot open included file $options->{filename} : file not found.")
              unless defined($filepath);
            # we'll need this for future reference - to call stat() for example.
            $options->{filepath} = $filepath;
        }

        # use the open_mode if we have one
        if (my $mode = $options->{open_mode}) {
            open(TEMPLATE, $mode, $filepath)
              || confess("HTML::Template->new() : Cannot open included file $filepath with mode $mode: $!");
        } else {
            open(TEMPLATE, $filepath)
              or confess("HTML::Template->new() : Cannot open included file $filepath : $!");
        }

        $self->{mtime} = $self->_mtime($filepath);

        # read into scalar, note the mtime for the record
        $self->{template} = "";
        while (read(TEMPLATE, $self->{template}, 10240, length($self->{template}))) { }
        close(TEMPLATE);

    } elsif (exists($options->{scalarref})) {
        # copy in the template text
        $self->{template} = ${$options->{scalarref}};

        delete($options->{scalarref});
    } elsif (exists($options->{arrayref})) {
        # if we have an array ref, join and store the template text
        $self->{template} = join("", @{$options->{arrayref}});

        delete($options->{arrayref});
    } elsif (exists($options->{filehandle})) {
        # just read everything in in one go
        local $/ = undef;
        $self->{template} = readline($options->{filehandle});

        delete($options->{filehandle});
    } else {
        confess("HTML::Template : Need to call new with filename, filehandle, scalarref or arrayref parameter specified.");
    }

    print STDERR "### HTML::Template Memory Debug ### END INIT_TEMPLATE ", $self->{proc_mem}->size(), "\n"
      if $options->{memory_debug};

    # handle filters if necessary
    $self->_call_filters(\$self->{template}) if @{$options->{filter}};

    return $self;
}

# handle calling user defined filters
sub _call_filters {
    my $self         = shift;
    my $template_ref = shift;
    my $options      = $self->{options};

    my ($format, $sub);
    foreach my $filter (@{$options->{filter}}) {
        croak("HTML::Template->new() : bad value set for filter parameter - must be a code ref or a hash ref.")
          unless ref $filter;

        # translate into CODE->HASH
        $filter = {'format' => 'scalar', 'sub' => $filter}
          if (ref $filter eq 'CODE');

        if (ref $filter eq 'HASH') {
            $format = $filter->{'format'};
            $sub    = $filter->{'sub'};

            # check types and values
            croak(
                "HTML::Template->new() : bad value set for filter parameter - hash must contain \"format\" key and \"sub\" key.")
              unless defined $format and defined $sub;
            croak("HTML::Template->new() : bad value set for filter parameter - \"format\" must be either 'array' or 'scalar'")
              unless $format eq 'array'
                  or $format eq 'scalar';
            croak("HTML::Template->new() : bad value set for filter parameter - \"sub\" must be a code ref")
              unless ref $sub and ref $sub eq 'CODE';

            # catch errors
            eval {
                if ($format eq 'scalar')
                {
                    # call
                    $sub->($template_ref);
                } else {
                    # modulate
                    my @array = map { $_ . "\n" } split("\n", $$template_ref);
                    # call
                    $sub->(\@array);
                    # demodulate
                    $$template_ref = join("", @array);
                }
            };
            croak("HTML::Template->new() : fatal error occured during filter call: $@") if $@;
        } else {
            croak("HTML::Template->new() : bad value set for filter parameter - must be code ref or hash ref");
        }
    }
    # all done
    return $template_ref;
}

# _parse sifts through a template building up the param_map and
# parse_stack structures.
#
# The end result is a Template object that is fully ready for
# output().
sub _parse {
    my $self    = shift;
    my $options = $self->{options};

    $options->{debug} and print STDERR "### HTML::Template Debug ### In _parse:\n";

    # setup the stacks and maps - they're accessed by typeglobs that
    # reference the top of the stack.  They are masked so that a loop
    # can transparently have its own versions.
    use vars qw(@pstack %pmap @ifstack @ucstack %top_pmap);
    local (*pstack, *ifstack, *pmap, *ucstack, *top_pmap);

    # the pstack is the array of scalar refs (plain text from the
    # template file), VARs, LOOPs, IFs and ELSEs that output() works on
    # to produce output.  Looking at output() should make it clear what
    # _parse is trying to accomplish.
    my @pstacks = ([]);
    *pstack = $pstacks[0];
    $self->{parse_stack} = $pstacks[0];

    # the pmap binds names to VARs, LOOPs and IFs.  It allows param() to
    # access the right variable.  NOTE: output() does not look at the
    # pmap at all!
    my @pmaps = ({});
    *pmap              = $pmaps[0];
    *top_pmap          = $pmaps[0];
    $self->{param_map} = $pmaps[0];

    # the ifstack is a temporary stack containing pending ifs and elses
    # waiting for a /if.
    my @ifstacks = ([]);
    *ifstack = $ifstacks[0];

    # the ucstack is a temporary stack containing conditions that need
    # to be bound to param_map entries when their block is finished.
    # This happens when a conditional is encountered before any other
    # reference to its NAME.  Since a conditional can reference VARs and
    # LOOPs it isn't possible to make the link right away.
    my @ucstacks = ([]);
    *ucstack = $ucstacks[0];

    # the loopstack is another temp stack for closing loops.  unlike
    # those above it doesn't get scoped inside loops, therefore it
    # doesn't need the typeglob magic.
    my @loopstack = ();

    # the fstack is a stack of filenames and counters that keeps track
    # of which file we're in and where we are in it.  This allows
    # accurate error messages even inside included files!
    # fcounter, fmax and fname are aliases for the current file's info
    use vars qw($fcounter $fname $fmax);
    local (*fcounter, *fname, *fmax);

    my @fstack = ([$options->{filepath} || "/fake/path/for/non/file/template", 1, scalar @{[$self->{template} =~ m/(\n)/g]} + 1]);
    (*fname, *fcounter, *fmax) = \(@{$fstack[0]});

    my $NOOP      = HTML::Template::NOOP->new();
    my $ESCAPE    = HTML::Template::ESCAPE->new();
    my $JSESCAPE  = HTML::Template::JSESCAPE->new();
    my $URLESCAPE = HTML::Template::URLESCAPE->new();

    # all the tags that need NAMEs:
    my %need_names = map { $_ => 1 } qw(TMPL_VAR TMPL_LOOP TMPL_IF TMPL_UNLESS TMPL_INCLUDE);

    # variables used below that don't need to be my'd in the loop
    my ($name, $which, $escape, $default);

    # handle the old vanguard format
    $options->{vanguard_compatibility_mode}
      and $self->{template} =~ s/%([-\w\/\.+]+)%/<TMPL_VAR NAME=$1>/g;

    # now split up template on '<', leaving them in
    my @chunks = split(m/(?=<)/, $self->{template});

    # all done with template
    delete $self->{template};

    # loop through chunks, filling up pstack
    my $last_chunk = $#chunks;
  CHUNK: for (my $chunk_number = 0 ; $chunk_number <= $last_chunk ; $chunk_number++) {
        next unless defined $chunks[$chunk_number];
        my $chunk = $chunks[$chunk_number];

        # a general regex to match any and all TMPL_* tags
        if (
            $chunk =~ /^<
                    (?:!--\s*)?
                    (
                      \/?tmpl_
                      (?:
                         (?:var) | (?:loop) | (?:if) | (?:else) | (?:unless) | (?:include)
                      )
                    ) # $1 => $which - start of the tag

                    \s* 

                    # DEFAULT attribute
                    (?: default \s*=\s*
                      (?:
                        "([^">]*)"  # $2 => double-quoted DEFAULT value "
                        |
                        '([^'>]*)'  # $3 => single-quoted DEFAULT value
                        |
                        ([^\s=>]*)  # $4 => unquoted DEFAULT value
                      )
                    )?

                    \s*

                    # ESCAPE attribute
                    (?: escape \s*=\s*
                      (?:
                        (
                           (?:["']?0["']?)|
                           (?:["']?1["']?)|
                           (?:["']?html["']?) |
                           (?:["']?url["']?) |
                           (?:["']?js["']?) |
                           (?:["']?none["']?)
                         )                         # $5 => ESCAPE on
                       )
                    )* # allow multiple ESCAPEs

                    \s*

                    # DEFAULT attribute
                    (?: default \s*=\s*
                      (?:
                        "([^">]*)"  # $6 => double-quoted DEFAULT value "
                        |
                        '([^'>]*)'  # $7 => single-quoted DEFAULT value
                        |
                        ([^\s=>]*)  # $8 => unquoted DEFAULT value
                      )
                    )?

                    \s*                    

                    # NAME attribute
                    (?:
                      (?: name \s*=\s*)?
                      (?:
                        "([^">]*)"  # $9 => double-quoted NAME value "
                        |
                        '([^'>]*)'  # $10 => single-quoted NAME value
                        |
                        ([^\s=>]*)  # $11 => unquoted NAME value
                      )
                    )? 
                    
                    \s*

                    # DEFAULT attribute
                    (?: default \s*=\s*
                      (?:
                        "([^">]*)"  # $12 => double-quoted DEFAULT value "
                        |
                        '([^'>]*)'  # $13 => single-quoted DEFAULT value
                        |
                        ([^\s=>]*)  # $14 => unquoted DEFAULT value
                      )
                    )?

                    \s*

                    # ESCAPE attribute
                    (?: escape \s*=\s*
                      (?:
                        (
                           (?:["']?0["']?)|
                           (?:["']?1["']?)|
                           (?:["']?html["']?) |
                           (?:["']?url["']?) |
                           (?:["']?js["']?) |
                           (?:["']?none["']?)
                         )                         # $15 => ESCAPE on
                       )
                    )* # allow multiple ESCAPEs

                    \s*

                    # DEFAULT attribute
                    (?: default \s*=\s*
                      (?:
                        "([^">]*)"  # $16 => double-quoted DEFAULT value "
                        |
                        '([^'>]*)'  # $17 => single-quoted DEFAULT value
                        |
                        ([^\s=>]*)  # $18 => unquoted DEFAULT value
                      )
                    )?

                    \s*

                    (?:--)?\/?>                    
                    (.*) # $19 => $post - text that comes after the tag
                   $/isx
          )
        {

            $which = uc($1);    # which tag is it

            $escape =
                defined $5  ? $5
              : defined $15 ? $15
              : (defined $options->{default_escape} && $which eq 'TMPL_VAR') ? $options->{default_escape}
              :                                                                0;                           # escape set?

            # what name for the tag?  undef for a /tag at most, one of the
            # following three will be defined
            $name = defined $9 ? $9 : defined $10 ? $10 : defined $11 ? $11 : undef;

            # is there a default?
            $default =
                defined $2  ? $2
              : defined $3  ? $3
              : defined $4  ? $4
              : defined $6  ? $6
              : defined $7  ? $7
              : defined $8  ? $8
              : defined $12 ? $12
              : defined $13 ? $13
              : defined $14 ? $14
              : defined $16 ? $16
              : defined $17 ? $17
              : defined $18 ? $18
              :               undef;

            my $post = $19;    # what comes after on the line

            # allow mixed case in filenames, otherwise flatten
            $name = lc($name)
              unless (not defined $name or $which eq 'TMPL_INCLUDE' or $options->{case_sensitive});

            # die if we need a name and didn't get one
            die "HTML::Template->new() : No NAME given to a $which tag at $fname : line $fcounter."
              if ($need_names{$which} and (not defined $name or not length $name));

            # die if we got an escape but can't use one
            die "HTML::Template->new() : ESCAPE option invalid in a $which tag at $fname : line $fcounter."
              if ($escape and ($which ne 'TMPL_VAR'));

            # die if we got a default but can't use one
            die "HTML::Template->new() : DEFAULT option invalid in a $which tag at $fname : line $fcounter."
              if (defined $default and ($which ne 'TMPL_VAR'));

            # take actions depending on which tag found
            if ($which eq 'TMPL_VAR') {
                $options->{debug}
                  and print STDERR "### HTML::Template Debug ### $fname : line $fcounter : parsed VAR $name\n";

                # if we already have this var, then simply link to the existing
                # HTML::Template::VAR, else create a new one.
                my $var;
                if (exists $pmap{$name}) {
                    $var = $pmap{$name};
                    (ref($var) eq 'HTML::Template::VAR')
                      or die
                      "HTML::Template->new() : Already used param name $name as a TMPL_LOOP, found in a TMPL_VAR at $fname : line $fcounter.";
                } else {
                    $var             = HTML::Template::VAR->new();
                    $pmap{$name}     = $var;
                    $top_pmap{$name} = HTML::Template::VAR->new()
                      if $options->{global_vars} and not exists $top_pmap{$name};
                }

                # if a DEFAULT was provided, push a DEFAULT object on the
                # stack before the variable.
                if (defined $default) {
                    push(@pstack, HTML::Template::DEFAULT->new($default));
                }

                # if ESCAPE was set, push an ESCAPE op on the stack before
                # the variable.  output will handle the actual work.
                # unless of course, they have set escape=0 or escape=none
                if ($escape) {
                    if ($escape =~ /^["']?url["']?$/i) {
                        push(@pstack, $URLESCAPE);
                    } elsif ($escape =~ /^["']?js["']?$/i) {
                        push(@pstack, $JSESCAPE);
                    } elsif ($escape =~ /^["']?0["']?$/) {
                        # do nothing if escape=0
                    } elsif ($escape =~ /^["']?none["']?$/i) {
                        # do nothing if escape=none
                    } else {
                        push(@pstack, $ESCAPE);
                    }
                }

                push(@pstack, $var);

            } elsif ($which eq 'TMPL_LOOP') {
                # we've got a loop start
                $options->{debug}
                  and print STDERR "### HTML::Template Debug ### $fname : line $fcounter : LOOP $name start\n";

                # if we already have this loop, then simply link to the existing
                # HTML::Template::LOOP, else create a new one.
                my $loop;
                if (exists $pmap{$name}) {
                    $loop = $pmap{$name};
                    (ref($loop) eq 'HTML::Template::LOOP')
                      or die
                      "HTML::Template->new() : Already used param name $name as a TMPL_VAR, TMPL_IF or TMPL_UNLESS, found in a TMP_LOOP at $fname : line $fcounter!";

                } else {
                    # store the results in a LOOP object - actually just a
                    # thin wrapper around another HTML::Template object.
                    $loop = HTML::Template::LOOP->new();
                    $pmap{$name} = $loop;
                }

                # get it on the loopstack, pstack of the enclosing block
                push(@pstack, $loop);
                push(@loopstack, [$loop, $#pstack]);

                # magic time - push on a fresh pmap and pstack, adjust the typeglobs.
                # this gives the loop a separate namespace (i.e. pmap and pstack).
                push(@pstacks, []);
                *pstack = $pstacks[$#pstacks];
                push(@pmaps, {});
                *pmap = $pmaps[$#pmaps];
                push(@ifstacks, []);
                *ifstack = $ifstacks[$#ifstacks];
                push(@ucstacks, []);
                *ucstack = $ucstacks[$#ucstacks];

                # auto-vivify __FIRST__, __LAST__ and __INNER__ if
                # loop_context_vars is set.  Otherwise, with
                # die_on_bad_params set output() will might cause errors
                # when it tries to set them.
                if ($options->{loop_context_vars}) {
                    $pmap{__first__}   = HTML::Template::VAR->new();
                    $pmap{__inner__}   = HTML::Template::VAR->new();
                    $pmap{__outer__}   = HTML::Template::VAR->new();
                    $pmap{__last__}    = HTML::Template::VAR->new();
                    $pmap{__odd__}     = HTML::Template::VAR->new();
                    $pmap{__even__}    = HTML::Template::VAR->new();
                    $pmap{__counter__} = HTML::Template::VAR->new();
                    $pmap{__index__}   = HTML::Template::VAR->new();
                }

            } elsif ($which eq '/TMPL_LOOP') {
                $options->{debug}
                  and print STDERR "### HTML::Template Debug ### $fname : line $fcounter : LOOP end\n";

                my $loopdata = pop(@loopstack);
                die "HTML::Template->new() : found </TMPL_LOOP> with no matching <TMPL_LOOP> at $fname : line $fcounter!"
                  unless defined $loopdata;

                my ($loop, $starts_at) = @$loopdata;

                # resolve pending conditionals
                foreach my $uc (@ucstack) {
                    my $var = $uc->[HTML::Template::COND::VARIABLE];
                    if (exists($pmap{$var})) {
                        $uc->[HTML::Template::COND::VARIABLE] = $pmap{$var};
                    } else {
                        $pmap{$var}     = HTML::Template::VAR->new();
                        $top_pmap{$var} = HTML::Template::VAR->new()
                          if $options->{global_vars} and not exists $top_pmap{$var};
                        $uc->[HTML::Template::COND::VARIABLE] = $pmap{$var};
                    }
                    if (ref($pmap{$var}) eq 'HTML::Template::VAR') {
                        $uc->[HTML::Template::COND::VARIABLE_TYPE] = HTML::Template::COND::VARIABLE_TYPE_VAR;
                    } else {
                        $uc->[HTML::Template::COND::VARIABLE_TYPE] = HTML::Template::COND::VARIABLE_TYPE_LOOP;
                    }
                }

                # get pmap and pstack for the loop, adjust the typeglobs to
                # the enclosing block.
                my $param_map = pop(@pmaps);
                *pmap = $pmaps[$#pmaps];
                my $parse_stack = pop(@pstacks);
                *pstack = $pstacks[$#pstacks];

                scalar(@ifstack)
                  and die
                  "HTML::Template->new() : Dangling <TMPL_IF> or <TMPL_UNLESS> in loop ending at $fname : line $fcounter.";
                pop(@ifstacks);
                *ifstack = $ifstacks[$#ifstacks];
                pop(@ucstacks);
                *ucstack = $ucstacks[$#ucstacks];

                # instantiate the sub-Template, feeding it parse_stack and
                # param_map.  This means that only the enclosing template
                # does _parse() - sub-templates get their parse_stack and
                # param_map fed to them already filled in.
                $loop->[HTML::Template::LOOP::TEMPLATE_HASH]{$starts_at} = ref($self)->_new_from_loop(
                    parse_stack        => $parse_stack,
                    param_map          => $param_map,
                    debug              => $options->{debug},
                    die_on_bad_params  => $options->{die_on_bad_params},
                    loop_context_vars  => $options->{loop_context_vars},
                    case_sensitive     => $options->{case_sensitive},
                    force_untaint      => $options->{force_untaint},
                    parent_global_vars => ($options->{global_vars} || $options->{parent_global_vars} || 0)
                );

                # if this loop has been used multiple times we need to merge the "param_map" between them
                # all so that die_on_bad_params doesn't complain if we try to use different vars in
                # each instance of the same loop
                if ($options->{die_on_bad_params}) {
                    my $loops = $loop->[HTML::Template::LOOP::TEMPLATE_HASH];
                    my @loop_keys = sort { $a <=> $b } keys %$loops;
                    if (@loop_keys > 1) {
                        my $last_loop = pop(@loop_keys);
                        foreach my $loop (@loop_keys) {
                            # make sure all the params in the last loop are also in this loop
                            foreach my $param (keys %{$loops->{$last_loop}->{param_map}}) {
                                next if $loops->{$loop}->{param_map}->{$param};
                                $loops->{$loop}->{param_map}->{$param} = $loops->{$last_loop}->{param_map}->{$param};
                            }
                            # make sure all the params in this loop are also in the last loop
                            foreach my $param (keys %{$loops->{$loop}->{param_map}}) {
                                next if $loops->{$last_loop}->{param_map}->{$param};
                                $loops->{$last_loop}->{param_map}->{$param} = $loops->{$loop}->{param_map}->{$param};
                            }
                        }
                    }
                }

            } elsif ($which eq 'TMPL_IF' or $which eq 'TMPL_UNLESS') {
                $options->{debug}
                  and print STDERR "### HTML::Template Debug ### $fname : line $fcounter : $which $name start\n";

                # if we already have this var, then simply link to the existing
                # HTML::Template::VAR/LOOP, else defer the mapping
                my $var;
                if (exists $pmap{$name}) {
                    $var = $pmap{$name};
                } else {
                    $var = $name;
                }

                # connect the var to a conditional
                my $cond = HTML::Template::COND->new($var);
                if ($which eq 'TMPL_IF') {
                    $cond->[HTML::Template::COND::WHICH]        = HTML::Template::COND::WHICH_IF;
                    $cond->[HTML::Template::COND::JUMP_IF_TRUE] = 0;
                } else {
                    $cond->[HTML::Template::COND::WHICH]        = HTML::Template::COND::WHICH_UNLESS;
                    $cond->[HTML::Template::COND::JUMP_IF_TRUE] = 1;
                }

                # push unconnected conditionals onto the ucstack for
                # resolution later.  Otherwise, save type information now.
                if ($var eq $name) {
                    push(@ucstack, $cond);
                } else {
                    if (ref($var) eq 'HTML::Template::VAR') {
                        $cond->[HTML::Template::COND::VARIABLE_TYPE] = HTML::Template::COND::VARIABLE_TYPE_VAR;
                    } else {
                        $cond->[HTML::Template::COND::VARIABLE_TYPE] = HTML::Template::COND::VARIABLE_TYPE_LOOP;
                    }
                }

                # push what we've got onto the stacks
                push(@pstack,  $cond);
                push(@ifstack, $cond);

            } elsif ($which eq '/TMPL_IF' or $which eq '/TMPL_UNLESS') {
                $options->{debug}
                  and print STDERR "### HTML::Template Debug ### $fname : line $fcounter : $which end\n";

                my $cond = pop(@ifstack);
                die "HTML::Template->new() : found </${which}> with no matching <TMPL_IF> at $fname : line $fcounter."
                  unless defined $cond;
                if ($which eq '/TMPL_IF') {
                    die
                      "HTML::Template->new() : found </TMPL_IF> incorrectly terminating a <TMPL_UNLESS> (use </TMPL_UNLESS>) at $fname : line $fcounter.\n"
                      if ($cond->[HTML::Template::COND::WHICH] == HTML::Template::COND::WHICH_UNLESS);
                } else {
                    die
                      "HTML::Template->new() : found </TMPL_UNLESS> incorrectly terminating a <TMPL_IF> (use </TMPL_IF>) at $fname : line $fcounter.\n"
                      if ($cond->[HTML::Template::COND::WHICH] == HTML::Template::COND::WHICH_IF);
                }

                # connect the matching to this "address" - place a NOOP to
                # hold the spot.  This allows output() to treat an IF in the
                # assembler-esque "Conditional Jump" mode.
                push(@pstack, $NOOP);
                $cond->[HTML::Template::COND::JUMP_ADDRESS] = $#pstack;

            } elsif ($which eq 'TMPL_ELSE') {
                $options->{debug}
                  and print STDERR "### HTML::Template Debug ### $fname : line $fcounter : ELSE\n";

                my $cond = pop(@ifstack);
                die
                  "HTML::Template->new() : found <TMPL_ELSE> with no matching <TMPL_IF> or <TMPL_UNLESS> at $fname : line $fcounter."
                  unless defined $cond;
                die
                  "HTML::Template->new() : found second <TMPL_ELSE> tag for  <TMPL_IF> or <TMPL_UNLESS> at $fname : line $fcounter."
                  if $cond->[HTML::Template::COND::IS_ELSE];

                my $else = HTML::Template::COND->new($cond->[HTML::Template::COND::VARIABLE]);
                $else->[HTML::Template::COND::WHICH]              = $cond->[HTML::Template::COND::WHICH];
                $else->[HTML::Template::COND::UNCONDITIONAL_JUMP] = 1;
                $else->[HTML::Template::COND::IS_ELSE]            = 1;

                # need end-block resolution?
                if (defined($cond->[HTML::Template::COND::VARIABLE_TYPE])) {
                    $else->[HTML::Template::COND::VARIABLE_TYPE] = $cond->[HTML::Template::COND::VARIABLE_TYPE];
                } else {
                    push(@ucstack, $else);
                }

                push(@pstack,  $else);
                push(@ifstack, $else);

                # connect the matching to this "address" - thus the if,
                # failing jumps to the ELSE address.  The else then gets
                # elaborated, and of course succeeds.  On the other hand, if
                # the IF fails and falls though, output will reach the else
                # and jump to the /if address.
                $cond->[HTML::Template::COND::JUMP_ADDRESS] = $#pstack;

            } elsif ($which eq 'TMPL_INCLUDE') {
                # handle TMPL_INCLUDEs
                $options->{debug}
                  and print STDERR "### HTML::Template Debug ### $fname : line $fcounter : INCLUDE $name \n";

                # no includes here, bub
                $options->{no_includes}
                  and croak("HTML::Template : Illegal attempt to use TMPL_INCLUDE in template file : (no_includes => 1)");

                my $filename = $name;

                # look for the included file...
                my $filepath;
                if ($options->{search_path_on_include}) {
                    $filepath = $self->_find_file($filename);
                } else {
                    $filepath = $self->_find_file($filename, [File::Spec->splitdir($fstack[-1][0])]);
                }
                die "HTML::Template->new() : Cannot open included file $filename : file not found."
                  if !defined $filepath  && $options->{die_on_missing_include};

                my $included_template = "";
                if( $filepath ) {
                    # use the open_mode if we have one
                    if (my $mode = $options->{open_mode}) {
                        open(TEMPLATE, $mode, $filepath)
                          || confess("HTML::Template->new() : Cannot open included file $filepath with mode $mode: $!");
                    } else {
                        open(TEMPLATE, $filepath)
                          or confess("HTML::Template->new() : Cannot open included file $filepath : $!");
                    }

                    # read into the array
                    while (read(TEMPLATE, $included_template, 10240, length($included_template))) { }
                    close(TEMPLATE);
                }

                # call filters if necessary
                $self->_call_filters(\$included_template) if @{$options->{filter}};

                if ($included_template) {    # not empty
                                             # handle the old vanguard format - this needs to happen here
                                             # since we're not about to do a next CHUNKS.
                    $options->{vanguard_compatibility_mode}
                      and $included_template =~ s/%([-\w\/\.+]+)%/<TMPL_VAR NAME=$1>/g;

                    # collect mtimes for included files
                    if ($options->{cache} and !$options->{blind_cache}) {
                        $self->{included_mtimes}{$filepath} = (stat($filepath))[9];
                    }

                    # adjust the fstack to point to the included file info
                    push(@fstack, [$filepath, 1, scalar @{[$included_template =~ m/(\n)/g]} + 1]);
                    (*fname, *fcounter, *fmax) = \(@{$fstack[$#fstack]});

                    # make sure we aren't infinitely recursing
                    die
                      "HTML::Template->new() : likely recursive includes - parsed $options->{max_includes} files deep and giving up (set max_includes higher to allow deeper recursion)."
                      if ($options->{max_includes}
                        and (scalar(@fstack) > $options->{max_includes}));

                    # stick the remains of this chunk onto the bottom of the
                    # included text.
                    $included_template .= $post;
                    $post = undef;

                    # move the new chunks into place.
                    splice(@chunks, $chunk_number, 1, split(m/(?=<)/, $included_template));

                    # recalculate stopping point
                    $last_chunk = $#chunks;

                    # start in on the first line of the included text - nothing
                    # else to do on this line.
                    $chunk = $chunks[$chunk_number];

                    redo CHUNK;
                }
            } else {
                # zuh!?
                die "HTML::Template->new() : Unknown or unmatched TMPL construct at $fname : line $fcounter.";
            }
            # push the rest after the tag
            if (defined($post)) {
                if (ref($pstack[$#pstack]) eq 'SCALAR') {
                    ${$pstack[$#pstack]} .= $post;
                } else {
                    push(@pstack, \$post);
                }
            }
        } else {    # just your ordinary markup
                    # make sure we didn't reject something TMPL_* but badly formed
            if ($options->{strict}) {
                die "HTML::Template->new() : Syntax error in <TMPL_*> tag at $fname : $fcounter."
                  if ($chunk =~ /<(?:!--\s*)?\/?tmpl_/i);
            }

            # push the rest and get next chunk
            if (defined($chunk)) {
                if (ref($pstack[$#pstack]) eq 'SCALAR') {
                    ${$pstack[$#pstack]} .= $chunk;
                } else {
                    push(@pstack, \$chunk);
                }
            }
        }
        # count newlines in chunk and advance line count
        $fcounter += scalar(@{[$chunk =~ m/(\n)/g]});
        # if we just crossed the end of an included file
        # pop off the record and re-alias to the enclosing file's info
        pop(@fstack), (*fname, *fcounter, *fmax) = \(@{$fstack[$#fstack]})
          if ($fcounter > $fmax);

    }    # next CHUNK

    # make sure we don't have dangling IF or LOOP blocks
    scalar(@ifstack)
      and die "HTML::Template->new() : At least one <TMPL_IF> or <TMPL_UNLESS> not terminated at end of file!";
    scalar(@loopstack)
      and die "HTML::Template->new() : At least one <TMPL_LOOP> not terminated at end of file!";

    # resolve pending conditionals
    foreach my $uc (@ucstack) {
        my $var = $uc->[HTML::Template::COND::VARIABLE];
        if (exists($pmap{$var})) {
            $uc->[HTML::Template::COND::VARIABLE] = $pmap{$var};
        } else {
            $pmap{$var}     = HTML::Template::VAR->new();
            $top_pmap{$var} = HTML::Template::VAR->new()
              if $options->{global_vars} and not exists $top_pmap{$var};
            $uc->[HTML::Template::COND::VARIABLE] = $pmap{$var};
        }
        if (ref($pmap{$var}) eq 'HTML::Template::VAR') {
            $uc->[HTML::Template::COND::VARIABLE_TYPE] = HTML::Template::COND::VARIABLE_TYPE_VAR;
        } else {
            $uc->[HTML::Template::COND::VARIABLE_TYPE] = HTML::Template::COND::VARIABLE_TYPE_LOOP;
        }
    }

    # want a stack dump?
    if ($options->{stack_debug}) {
        require 'Data/Dumper.pm';
        print STDERR "### HTML::Template _param Stack Dump ###\n\n", Data::Dumper::Dumper($self->{parse_stack}), "\n";
    }

    # get rid of filters - they cause runtime errors if Storable tries
    # to store them.  This can happen under global_vars.
    delete $options->{filter};
}

# a recursive sub that associates each loop with the loops above
# (treating the top-level as a loop)
sub _globalize_vars {
    my $self = shift;

    # associate with the loop (and top-level templates) above in the tree.
    push(@{$self->{options}{associate}}, @_);

    # recurse down into the template tree, adding ourself to the end of
    # list.
    push(@_, $self);
    map   { $_->_globalize_vars(@_) }
      map { values %{$_->[HTML::Template::LOOP::TEMPLATE_HASH]} }
      grep { ref($_) eq 'HTML::Template::LOOP' } @{$self->{parse_stack}};
}

# method used to recursively un-hook associate
sub _unglobalize_vars {
    my $self = shift;

    # disassociate
    $self->{options}{associate} = undef;

    # recurse down into the template tree disassociating
    map   { $_->_unglobalize_vars() }
      map { values %{$_->[HTML::Template::LOOP::TEMPLATE_HASH]} }
      grep { ref($_) eq 'HTML::Template::LOOP' } @{$self->{parse_stack}};
}

=head2 param

C<param()> can be called in a number of ways

=over

=item 1 - To return a list of parameters in the template : 

    my @parameter_names = $self->param();

=item 2 - To return the value set to a param : 

    my $value = $self->param('PARAM');

=item 3 - To set the value of a parameter :

    # For simple TMPL_VARs:
    $self->param(PARAM => 'value');

    # with a subroutine reference that gets called to get the value
    # of the scalar.  The sub will receive the template object as a
    # parameter.
    $self->param(PARAM => sub { return 'value' });

    # And TMPL_LOOPs:
    $self->param(LOOP_PARAM => [{PARAM => VALUE_FOR_FIRST_PASS}, {PARAM => VALUE_FOR_SECOND_PASS}]);

=item 4 - To set the value of a a number of parameters :

    # For simple TMPL_VARs:
    $self->param(
        PARAM  => 'value',
        PARAM2 => 'value'
    );

    # And with some TMPL_LOOPs:
    $self->param(
        PARAM              => 'value',
        PARAM2             => 'value',
        LOOP_PARAM         => [{PARAM => VALUE_FOR_FIRST_PASS}, {PARAM => VALUE_FOR_SECOND_PASS}],
        ANOTHER_LOOP_PARAM => [{PARAM => VALUE_FOR_FIRST_PASS}, {PARAM => VALUE_FOR_SECOND_PASS}],
    );
=item 5 - To set the value of a a number of parameters using a hash-ref :

    $self->param(
        {
            PARAM              => 'value',
            PARAM2             => 'value',
            LOOP_PARAM         => [{PARAM => VALUE_FOR_FIRST_PASS}, {PARAM => VALUE_FOR_SECOND_PASS}],
            ANOTHER_LOOP_PARAM => [{PARAM => VALUE_FOR_FIRST_PASS}, {PARAM => VALUE_FOR_SECOND_PASS}],
        }
    );

An error occurs if you try to set a value that is tainted if the C<force_untaint>
option is set.

=back

=cut

sub param {
    my $self      = shift;
    my $options   = $self->{options};
    my $param_map = $self->{param_map};

    # the no-parameter case - return list of parameters in the template.
    return keys(%$param_map) unless scalar(@_);

    my $first = shift;
    my $type  = ref $first;

    # the one-parameter case - could be a parameter value request or a
    # hash-ref.
    if (!scalar(@_) and !length($type)) {
        my $param = $options->{case_sensitive} ? $first : lc $first;

        # check for parameter existence
        $options->{die_on_bad_params}
          and !exists($param_map->{$param})
          and croak(
            "HTML::Template : Attempt to get nonexistent parameter '$param' - this parameter name doesn't match any declarations in the template file : (die_on_bad_params set => 1)"
          );

        return undef unless (exists($param_map->{$param})
            and defined($param_map->{$param}));

        return ${$param_map->{$param}}
          if (ref($param_map->{$param}) eq 'HTML::Template::VAR');
        return $param_map->{$param}[HTML::Template::LOOP::PARAM_SET];
    }

    if (!scalar(@_)) {
        croak("HTML::Template->param() : Single reference arg to param() must be a hash-ref!  You gave me a $type.")
          unless $type eq 'HASH'
              or UNIVERSAL::isa($first, 'HASH');
        push(@_, %$first);
    } else {
        unshift(@_, $first);
    }

    croak("HTML::Template->param() : You gave me an odd number of parameters to param()!")
      unless ((@_ % 2) == 0);

    # strangely, changing this to a "while(@_) { shift, shift }" type
    # loop causes perl 5.004_04 to die with some nonsense about a
    # read-only value.
    for (my $x = 0 ; $x <= $#_ ; $x += 2) {
        my $param = $options->{case_sensitive} ? $_[$x] : lc $_[$x];
        my $value = $_[($x + 1)];

        # check that this param exists in the template
        $options->{die_on_bad_params}
          and !exists($param_map->{$param})
          and croak(
            "HTML::Template : Attempt to set nonexistent parameter '$param' - this parameter name doesn't match any declarations in the template file : (die_on_bad_params => 1)"
          );

        # if we're not going to die from bad param names, we need to ignore
        # them...
        unless (exists($param_map->{$param})) {
            next if not $options->{parent_global_vars};

            # ... unless global vars is on - in which case we can't be
            # sure we won't need it in a lower loop.
            if (ref($value) eq 'ARRAY') {
                $param_map->{$param} = HTML::Template::LOOP->new();
            } else {
                $param_map->{$param} = HTML::Template::VAR->new();
            }
        }

        # figure out what we've got, taking special care to allow for
        # objects that are compatible underneath.
        my $type = ref $value || '';
        if ($type eq 'REF') {
            croak("HTML::Template::param() : attempt to set parameter '$param' with a reference to a reference!");
        } elsif ($type && ($type eq 'ARRAY' || ($type !~ /^(CODE)|(HASH)|(SCALAR)$/ && $value->isa('ARRAY')))) {
            ref($param_map->{$param}) eq 'HTML::Template::LOOP'
              || croak(
                "HTML::Template::param() : attempt to set parameter '$param' with an array ref - parameter is not a TMPL_LOOP!");
            $param_map->{$param}[HTML::Template::LOOP::PARAM_SET] = [@{$value}];
        } elsif( $type eq 'CODE' ) {
            # code can be used for a var or a loop
            if( ref($param_map->{$param}) eq 'HTML::Template::LOOP' ) {
                $param_map->{$param}[HTML::Template::LOOP::PARAM_SET] = $value;
            } else {
                ${$param_map->{$param}} = $value;
            }
        } else {
            ref($param_map->{$param}) eq 'HTML::Template::VAR'
              || croak(
                "HTML::Template::param() : attempt to set parameter '$param' with a scalar - parameter is not a TMPL_VAR!");
            ${$param_map->{$param}} = $value;
        }
    }
}

=head2 clear_params

Sets all the parameters to undef. Useful internally, if nowhere else!

=cut

sub clear_params {
    my $self = shift;
    my $type;
    foreach my $name (keys %{$self->{param_map}}) {
        $type = ref($self->{param_map}{$name});
        undef(${$self->{param_map}{$name}})
          if ($type eq 'HTML::Template::VAR');
        undef($self->{param_map}{$name}[HTML::Template::LOOP::PARAM_SET])
          if ($type eq 'HTML::Template::LOOP');
    }
}

# obsolete implementation of associate
sub associateCGI {
    my $self = shift;
    my $cgi  = shift;
    (ref($cgi) eq 'CGI')
      or croak("Warning! non-CGI object was passed to HTML::Template::associateCGI()!\n");
    push(@{$self->{options}{associate}}, $cgi);
    return 1;
}

=head2 output

C<output()> returns the final result of the template.  In most situations
you'll want to print this, like:

    print $template->output();

When output is called each occurrence of C<< <TMPL_VAR NAME=name> >> is
replaced with the value assigned to "name" via C<param()>.  If a named
parameter is unset it is simply replaced with ''.  C<< <TMPL_LOOPS> >>
are evaluated once per parameter set, accumlating output on each pass.

Calling C<output()> is guaranteed not to change the state of the
HTML::Template object, in case you were wondering.  This property is
mostly important for the internal implementation of loops.

You may optionally supply a filehandle to print to automatically as the
template is generated.  This may improve performance and lower memory
consumption.  Example:

    $template->output(print_to => *STDOUT);

The return value is undefined when using the C<print_to> option.

=cut

use vars qw(%URLESCAPE_MAP);

sub output {
    my $self    = shift;
    my $options = $self->{options};
    local $_;

    croak("HTML::Template->output() : You gave me an odd number of parameters to output()!")
      unless ((@_ % 2) == 0);
    my %args = @_;

    print STDERR "### HTML::Template Memory Debug ### START OUTPUT ", $self->{proc_mem}->size(), "\n"
      if $options->{memory_debug};

    $options->{debug} and print STDERR "### HTML::Template Debug ### In output\n";

    # want a stack dump?
    if ($options->{stack_debug}) {
        require 'Data/Dumper.pm';
        print STDERR "### HTML::Template output Stack Dump ###\n\n", Data::Dumper::Dumper($self->{parse_stack}), "\n";
    }

    # globalize vars - this happens here to localize the circular
    # references created by global_vars.
    $self->_globalize_vars() if ($options->{global_vars});

    # support the associate magic, searching for undefined params and
    # attempting to fill them from the associated objects.
    if (scalar(@{$options->{associate}})) {
        # prepare case-mapping hashes to do case-insensitive matching
        # against associated objects.  This allows CGI.pm to be
        # case-sensitive and still work with asssociate.
        my (%case_map, $lparam);
        foreach my $associated_object (@{$options->{associate}}) {
            # what a hack!  This should really be optimized out for case_sensitive.
            if ($options->{case_sensitive}) {
                map { $case_map{$associated_object}{$_} = $_ } $associated_object->param();
            } else {
                map { $case_map{$associated_object}{lc($_)} = $_ } $associated_object->param();
            }
        }

        foreach my $param (keys %{$self->{param_map}}) {
            unless (defined($self->param($param))) {
              OBJ: foreach my $associated_object (reverse @{$options->{associate}}) {
                    $self->param($param, scalar $associated_object->param($case_map{$associated_object}{$param})), last OBJ
                      if (exists($case_map{$associated_object}{$param}));
                }
            }
        }
    }

    use vars qw($line @parse_stack);
    local (*line, *parse_stack);

    # walk the parse stack, accumulating output in $result
    *parse_stack = $self->{parse_stack};
    my $result = '';

    tie $result, 'HTML::Template::PRINTSCALAR', $args{print_to}
      if defined $args{print_to} and not tied $args{print_to};

    my $type;
    my $parse_stack_length = $#parse_stack;
    for (my $x = 0 ; $x <= $parse_stack_length ; $x++) {
        *line = \$parse_stack[$x];
        $type = ref($line);

        if ($type eq 'SCALAR') {
            $result .= $$line;
        } elsif ($type eq 'HTML::Template::VAR' and ref($$line) eq 'CODE') {
            if (defined($$line)) {
                my $tmp_val = $$line->($self);
                croak("HTML::Template->output() : 'force_untaint' option but coderef returns tainted value") 
                  if $options->{force_untaint} && tainted($tmp_val);
                $result .= $tmp_val;

                # change the reference to point to the value now not the code reference
                $$line = $tmp_val if $options->{cache_lazy_vars}
            }
        } elsif ($type eq 'HTML::Template::VAR') {
            if (defined $$line) {
                if ($options->{force_untaint} && tainted($$line)) {
                    croak("HTML::Template->output() : tainted value with 'force_untaint' option");
                }
                $result .= $$line;
            }
        } elsif ($type eq 'HTML::Template::LOOP') {
            if (defined($line->[HTML::Template::LOOP::PARAM_SET])) {
                eval { $result .= $line->output($x, $options->{loop_context_vars}); };
                croak("HTML::Template->output() : fatal error in loop output : $@")
                  if $@;
            }
        } elsif ($type eq 'HTML::Template::COND') {

            if ($line->[HTML::Template::COND::UNCONDITIONAL_JUMP]) {
                $x = $line->[HTML::Template::COND::JUMP_ADDRESS];
            } else {
                if ($line->[HTML::Template::COND::JUMP_IF_TRUE]) {
                    if ($line->[HTML::Template::COND::VARIABLE_TYPE] == HTML::Template::COND::VARIABLE_TYPE_VAR) {
                        if (defined ${$line->[HTML::Template::COND::VARIABLE]}) {
                            if (ref(${$line->[HTML::Template::COND::VARIABLE]}) eq 'CODE') {
                                my $tmp_val = ${$line->[HTML::Template::COND::VARIABLE]}->($self); 
                                $x = $line->[HTML::Template::COND::JUMP_ADDRESS] if $tmp_val;
                                ${$line->[HTML::Template::COND::VARIABLE]} = $tmp_val if $options->{cache_lazy_vars};
                            } else {
                                $x = $line->[HTML::Template::COND::JUMP_ADDRESS] if ${$line->[HTML::Template::COND::VARIABLE]};
                            }
                        }
                    } else {
                        # if it's a code reference, execute it to get the values
                        my $loop_values = $line->[HTML::Template::COND::VARIABLE][HTML::Template::LOOP::PARAM_SET];
                        if (defined $loop_values && ref $loop_values eq 'CODE') {
                            $loop_values = $loop_values->($self);
                            $line->[HTML::Template::COND::VARIABLE][HTML::Template::LOOP::PARAM_SET] = $loop_values 
                              if $options->{cache_lazy_loops};
                        }

                        # if we have anything for the loop, jump to the next part
                        if (defined $loop_values && @$loop_values) {
                            $x = $line->[HTML::Template::COND::JUMP_ADDRESS];
                        }
                    }
                } else {
                    if ($line->[HTML::Template::COND::VARIABLE_TYPE] == HTML::Template::COND::VARIABLE_TYPE_VAR) {
                        if (defined ${$line->[HTML::Template::COND::VARIABLE]}) {
                            if (ref(${$line->[HTML::Template::COND::VARIABLE]}) eq 'CODE') {
                                my $tmp_val = ${$line->[HTML::Template::COND::VARIABLE]}->($self);
                                $x = $line->[HTML::Template::COND::JUMP_ADDRESS] unless $tmp_val;
                                ${$line->[HTML::Template::COND::VARIABLE]} = $tmp_val if $options->{cache_lazy_vars};
                            } else {
                                $x = $line->[HTML::Template::COND::JUMP_ADDRESS]
                                  unless ${$line->[HTML::Template::COND::VARIABLE]};
                            }
                        } else {
                            $x = $line->[HTML::Template::COND::JUMP_ADDRESS];
                        }
                    } else {
                        # if we don't have anything for the loop, jump to the next part
                        my $loop_values = $line->[HTML::Template::COND::VARIABLE][HTML::Template::LOOP::PARAM_SET];
                        if(!defined $loop_values) {
                            $x = $line->[HTML::Template::COND::JUMP_ADDRESS];
                        } else {
                            # check to see if the loop is a code ref and if it is execute it to get the values
                            if( ref $loop_values eq 'CODE' ) {
                                $loop_values = $line->[HTML::Template::COND::VARIABLE][HTML::Template::LOOP::PARAM_SET]->($self);
                                $line->[HTML::Template::COND::VARIABLE][HTML::Template::LOOP::PARAM_SET] = $loop_values
                                  if $options->{cache_lazy_loops};
                            }

                            # if we don't have anything in the loop, jump to the next part
                            if(!@$loop_values) {
                                $x = $line->[HTML::Template::COND::JUMP_ADDRESS];
                            }
                        }
                    }
                }
            }
        } elsif ($type eq 'HTML::Template::NOOP') {
            next;
        } elsif ($type eq 'HTML::Template::DEFAULT') {
            $_ = $x;    # remember default place in stack

            # find next VAR, there might be an ESCAPE in the way
            *line = \$parse_stack[++$x];
            *line = \$parse_stack[++$x]
              if ref $line eq 'HTML::Template::ESCAPE'
                  or ref $line eq 'HTML::Template::JSESCAPE'
                  or ref $line eq 'HTML::Template::URLESCAPE';

            # either output the default or go back
            if (defined $$line) {
                $x = $_;
            } else {
                $result .= ${$parse_stack[$_]};
            }
            next;
        } elsif ($type eq 'HTML::Template::ESCAPE') {
            *line = \$parse_stack[++$x];
            if (defined($$line)) {
                my $tmp_val;
                if (ref($$line) eq 'CODE') {
                    $tmp_val = $$line->($self);
                    if ($options->{force_untaint} > 1 && tainted($_)) {
                        croak("HTML::Template->output() : 'force_untaint' option but coderef returns tainted value");
                    }

                    $$line = $tmp_val if $options->{cache_lazy_vars};
                } else {
                    $tmp_val = $$line;
                    if ($options->{force_untaint} > 1 && tainted($_)) {
                        croak("HTML::Template->output() : tainted value with 'force_untaint' option");
                    }
                }

                # straight from the CGI.pm bible.
                $tmp_val =~ s/&/&amp;/g;
                $tmp_val =~ s/\"/&quot;/g;
                $tmp_val =~ s/>/&gt;/g;
                $tmp_val =~ s/</&lt;/g;
                $tmp_val =~ s/'/&#39;/g; 

                $result .= $tmp_val;
            }
            next;
        } elsif ($type eq 'HTML::Template::JSESCAPE') {
            $x++;
            *line = \$parse_stack[$x];
            if (defined($$line)) {
                my $tmp_val;
                if (ref($$line) eq 'CODE') {
                    $tmp_val = $$line->($self);
                    if ($options->{force_untaint} > 1 && tainted($_)) {
                        croak("HTML::Template->output() : 'force_untaint' option but coderef returns tainted value");
                    }
                    $$line = $tmp_val if $options->{cache_lazy_vars};
                } else {
                    $tmp_val = $$line;
                    if ($options->{force_untaint} > 1 && tainted($_)) {
                        croak("HTML::Template->output() : tainted value with 'force_untaint' option");
                    }
                }
                $tmp_val =~ s/\\/\\\\/g;
                $tmp_val =~ s/'/\\'/g;
                $tmp_val =~ s/"/\\"/g;
                $tmp_val =~ s/\n/\\n/g;
                $tmp_val =~ s/\r/\\r/g;
                $result .= $tmp_val;
            }
        } elsif ($type eq 'HTML::Template::URLESCAPE') {
            $x++;
            *line = \$parse_stack[$x];
            if (defined($$line)) {
                my $tmp_val;
                if (ref($$line) eq 'CODE') {
                    $tmp_val = $$line->($self);
                    if ($options->{force_untaint} > 1 && tainted($_)) {
                        croak("HTML::Template->output() : 'force_untaint' option but coderef returns tainted value");
                    }
                    $$line = $tmp_val if $options->{cache_lazy_vars};
                } else {
                    $tmp_val = $$line;
                    if ($options->{force_untaint} > 1 && tainted($_)) {
                        croak("HTML::Template->output() : tainted value with 'force_untaint' option");
                    }
                }
                # Build a char->hex map if one isn't already available
                unless (exists($URLESCAPE_MAP{chr(1)})) {
                    for (0 .. 255) { $URLESCAPE_MAP{chr($_)} = sprintf('%%%02X', $_); }
                }
                # do the translation (RFC 2396 ^uric)
                $tmp_val =~ s!([^a-zA-Z0-9_.\-])!$URLESCAPE_MAP{$1}!g;
                $result .= $tmp_val;
            }
        } else {
            confess("HTML::Template::output() : Unknown item in parse_stack : " . $type);
        }
    }

    # undo the globalization circular refs
    $self->_unglobalize_vars() if ($options->{global_vars});

    print STDERR "### HTML::Template Memory Debug ### END OUTPUT ", $self->{proc_mem}->size(), "\n"
      if $options->{memory_debug};

    return undef if defined $args{print_to};
    return $result;
}

=head2 query

This method allow you to get information about the template structure.
It can be called in a number of ways.  The simplest usage of query is
simply to check whether a parameter name exists in the template, using
the C<name> option:

    if ($template->query(name => 'foo')) {
        # do something if a varaible of any type named FOO is in the template
    }

This same usage returns the type of the parameter.  The type is the same
as the tag minus the leading 'TMPL_'.  So, for example, a C<TMPL_VAR>
parameter returns 'VAR' from C<query()>.

    if ($template->query(name => 'foo') eq 'VAR') {
        # do something if FOO exists and is a TMPL_VAR
    }

Note that the variables associated with C<TMPL_IF>s and C<TMPL_UNLESS>s
will be identified as 'VAR' unless they are also used in a C<TMPL_LOOP>,
in which case they will return 'LOOP'.

C<query()> also allows you to get a list of parameters inside a loop
(and inside loops inside loops).  Example loop:

    <TMPL_LOOP NAME="EXAMPLE_LOOP">
      <TMPL_VAR NAME="BEE">
      <TMPL_VAR NAME="BOP">
      <TMPL_LOOP NAME="EXAMPLE_INNER_LOOP">
        <TMPL_VAR NAME="INNER_BEE">
        <TMPL_VAR NAME="INNER_BOP">
      </TMPL_LOOP>
    </TMPL_LOOP>

And some query calls:
  
    # returns 'LOOP'
    $type = $template->query(name => 'EXAMPLE_LOOP');

    # returns ('bop', 'bee', 'example_inner_loop')
    @param_names = $template->query(loop => 'EXAMPLE_LOOP');

    # both return 'VAR'
    $type = $template->query(name => ['EXAMPLE_LOOP', 'BEE']);
    $type = $template->query(name => ['EXAMPLE_LOOP', 'BOP']);

    # and this one returns 'LOOP'
    $type = $template->query(name => ['EXAMPLE_LOOP', 'EXAMPLE_INNER_LOOP']);

    # and finally, this returns ('inner_bee', 'inner_bop')
    @inner_param_names = $template->query(loop => ['EXAMPLE_LOOP', 'EXAMPLE_INNER_LOOP']);

    # for non existent parameter names you get undef this returns undef.
    $type = $template->query(name => 'DWEAZLE_ZAPPA');

    # calling loop on a non-loop parameter name will cause an error. This dies:
    $type = $template->query(loop => 'DWEAZLE_ZAPPA');

As you can see above the C<loop> option returns a list of parameter
names and both C<name> and C<loop> take array refs in order to refer to
parameters inside loops.  It is an error to use C<loop> with a parameter
that is not a loop.

Note that all the names are returned in lowercase and the types are
uppercase.

Just like C<param()>, C<query()> with no arguments returns all the
parameter names in the template at the top level.

=cut

sub query {
    my $self = shift;
    $self->{options}{debug}
      and print STDERR "### HTML::Template Debug ### query(", join(', ', @_), ")\n";

    # the no-parameter case - return $self->param()
    return $self->param() unless scalar(@_);

    croak("HTML::Template::query() : Odd number of parameters passed to query!")
      if (scalar(@_) % 2);
    croak("HTML::Template::query() : Wrong number of parameters passed to query - should be 2.")
      if (scalar(@_) != 2);

    my ($opt, $path) = (lc shift, shift);
    croak("HTML::Template::query() : invalid parameter ($opt)")
      unless ($opt eq 'name' or $opt eq 'loop');

    # make path an array unless it already is
    $path = [$path] unless (ref $path);

    # find the param in question.
    my @objs = $self->_find_param(@$path);
    return undef unless scalar(@objs);
    my ($obj, $type);

    # do what the user asked with the object
    if ($opt eq 'name') {
        # we only look at the first one.  new() should make sure they're
        # all the same.
        ($obj, $type) = (shift(@objs), shift(@objs));
        return undef unless defined $obj;
        return 'VAR'  if $type eq 'HTML::Template::VAR';
        return 'LOOP' if $type eq 'HTML::Template::LOOP';
        croak("HTML::Template::query() : unknown object ($type) in param_map!");

    } elsif ($opt eq 'loop') {
        my %results;
        while (@objs) {
            ($obj, $type) = (shift(@objs), shift(@objs));
            croak(
                "HTML::Template::query() : Search path [",
                join(', ', @$path),
                "] doesn't end in a TMPL_LOOP - it is an error to use the 'loop' option on a non-loop parameter.  To avoid this problem you can use the 'name' option to query() to check the type first."
            ) unless ((defined $obj) and ($type eq 'HTML::Template::LOOP'));

            # SHAZAM!  This bit extracts all the parameter names from all the
            # loop objects for this name.
            map { $results{$_} = 1 }
              map { keys(%{$_->{'param_map'}}) } values(%{$obj->[HTML::Template::LOOP::TEMPLATE_HASH]});
        }
        # this is our loop list, return it.
        return keys(%results);
    }
}

# a function that returns the object(s) corresponding to a given path and
# its (their) ref()(s).  Used by query() in the obvious way.
sub _find_param {
    my $self = shift;
    my $spot = $self->{options}{case_sensitive} ? shift : lc shift;

    # get the obj and type for this spot
    my $obj = $self->{'param_map'}{$spot};
    return unless defined $obj;
    my $type = ref $obj;

    # return if we're here or if we're not but this isn't a loop
    return ($obj, $type) unless @_;
    return unless ($type eq 'HTML::Template::LOOP');

    # recurse.  this is a depth first seach on the template tree, for
    # the algorithm geeks in the audience.
    return map { $_->_find_param(@_) } values(%{$obj->[HTML::Template::LOOP::TEMPLATE_HASH]});
}

# HTML::Template::VAR, LOOP, etc are *light* objects - their internal
# spec is used above.  No encapsulation or information hiding is to be
# assumed.

package HTML::Template::VAR;

sub new {
    my $value;
    return bless(\$value, $_[0]);
}

package HTML::Template::DEFAULT;

sub new {
    my $value = $_[1];
    return bless(\$value, $_[0]);
}

package HTML::Template::LOOP;

sub new {
    return bless([], $_[0]);
}

sub output {
    my $self              = shift;
    my $index             = shift;
    my $loop_context_vars = shift;
    my $template          = $self->[TEMPLATE_HASH]{$index};
    my $value_sets_array  = $self->[PARAM_SET];
    return unless defined($value_sets_array);

    my $result = '';
    my $count  = 0;
    my $odd    = 0;

    # execute the code to get the values if it's a code reference
    if( ref $value_sets_array eq 'CODE' ) {
        $value_sets_array = $value_sets_array->($template);
        croak("HTML::Template->output: TMPL_LOOP code reference did not return an ARRAY reference!") 
          unless ref $value_sets_array && ref $value_sets_array eq 'ARRAY';
        $self->[PARAM_SET] = $value_sets_array if $template->{options}->{cache_lazy_loops};
    }

    foreach my $value_set (@$value_sets_array) {
        if ($loop_context_vars) {
            if ($count == 0) {
                @{$value_set}{qw(__first__ __inner__ __outer__ __last__)} = (1, 0, 1, $#{$value_sets_array} == 0);
            } elsif ($count == $#{$value_sets_array}) {
                @{$value_set}{qw(__first__ __inner__ __outer__ __last__)} = (0, 0, 1, 1);
            } else {
                @{$value_set}{qw(__first__ __inner__ __outer__ __last__)} = (0, 1, 0, 0);
            }
            $odd = $value_set->{__odd__} = !$odd;
            $value_set->{__even__} = !$odd;
            
            $value_set->{__counter__} = $count + 1;
            $value_set->{__index__}   = $count;
        }
        $template->param($value_set);
        $result .= $template->output;
        $template->clear_params;
        @{$value_set}{qw(__first__ __last__ __inner__ __outer__ __odd__ __event__ __counter__ __index__)} = (0, 0, 0, 0, 0, 0, 0)
          if ($loop_context_vars);
        $count++;
    }

    return $result;
}

package HTML::Template::COND;

sub new {
    my $pkg  = shift;
    my $var  = shift;
    my $self = [];
    $self->[VARIABLE] = $var;

    bless($self, $pkg);
    return $self;
}

package HTML::Template::NOOP;

sub new {
    my $unused;
    my $self = \$unused;
    bless($self, $_[0]);
    return $self;
}

package HTML::Template::ESCAPE;

sub new {
    my $unused;
    my $self = \$unused;
    bless($self, $_[0]);
    return $self;
}

package HTML::Template::JSESCAPE;

sub new {
    my $unused;
    my $self = \$unused;
    bless($self, $_[0]);
    return $self;
}

package HTML::Template::URLESCAPE;

sub new {
    my $unused;
    my $self = \$unused;
    bless($self, $_[0]);
    return $self;
}

# scalar-tying package for output(print_to => *HANDLE) implementation
package HTML::Template::PRINTSCALAR;
use strict;

sub TIESCALAR { bless \$_[1], $_[0]; }
sub FETCH { }

sub STORE {
    my $self = shift;
    local *FH = $$self;
    print FH @_;
}
1;
__END__

=head1 LAZY VALUES

As mentioned above, both C<TMPL_VAR> and C<TMPL_LOOP> values can be code
references.  These code references are only executed if the variable or
loop is used in the template.  This is extremely useful if you want to
make a variable available to template designers but it can be expensive
to calculate, so you only want to do so if you have to.

Maybe an example will help to illustrate. Let's say you have a template
like this:

    <tmpl_if we_care>
      <tmpl_if life_universe_and_everything>
    </tmpl_if>

If C<life_universe_and_everything> is expensive to calculate we can
wrap it's calculation in a code reference and HTML::Template will only
execute that code if C<we_care> is also true.

    $tmpl->param(life_universe_and_everything => sub { calculate_42() });

Your code reference will be given a single argument, the HTML::Template
object in use. In the above example, if we wanted C<calculate_42()>
to have this object we'd do something like this:

    $tmpl->param(life_universe_and_everything => sub { calculate_42(shift) });

This same approach can be used for C<TMPL_LOOP>s too:

    <tmpl_if we_care>
      <tmpl_loop needles_in_haystack>
        Found <tmpl_var __counter>!
      </tmpl_loop>
    </tmpl_if>

And in your Perl code:

    $tmpl->param(needles_in_haystack => sub { find_needles() });

The only difference in the C<TMPL_LOOP> case is that the subroutine
needs to return a reference to an ARRAY, not just a scalar value.

=head2 Multiple Calls

It's important to recognize that while this feature is designed
to save processing time when things aren't needed, if you're not
careful it can actually increase the number of times you perform your
calculation. HTML::Template calls your code reference each time it seems
your loop in the template, this includes the times that you might use
the loop in a conditional (C<TMPL_IF> or C<TMPL_UNLESS>). For instance:

    <tmpl_if we care>
      <tmpl_if needles_in_haystack>
          <tmpl_loop needles_in_haystack>
            Found <tmpl_var __counter>!
          </tmpl_loop>
      <tmpl_else>
        No needles found!
      </tmpl_if>
    </tmpl_if>

This will actually call C<find_needles()> twice which will be even worse
than you had before.  One way to work around this is to cache the return
value yourself:

    my $needles;
    $tmpl->param(needles_in_haystack => sub { defined $needles ? $needles : $needles = find_needles() });

=head1 BUGS

I am aware of no bugs - if you find one, join the mailing list and
tell us about it.  You can join the HTML::Template mailing-list by
visiting:

    http://lists.sourceforge.net/lists/listinfo/html-template-users

Of course, you can still email me directly (C<sam@tregar.com>) with bugs,
but I reserve the right to forward bug reports to the mailing list.

When submitting bug reports, be sure to include full details,
including the VERSION of the module, a test script and a test template
demonstrating the problem!

If you're feeling really adventurous, HTML::Template has a publically
available Subversion server.  See below for more information in the
PUBLIC SUBVERSION SERVER section.

=head1 CREDITS

This module was the brain child of my boss, Jesse Erlbaum
(C<jesse@vm.com>) at Vanguard Media (http://vm.com) .  The most original
idea in this module - the C<< <TMPL_LOOP> >> - was entirely his.

Fixes, Bug Reports, Optimizations and Ideas have been generously
provided by:

=over

=item * Richard Chen

=item * Mike Blazer

=item * Adriano Nagelschmidt Rodrigues

=item * Andrej Mikus

=item * Ilya Obshadko

=item * Kevin Puetz

=item * Steve Reppucci

=item * Richard Dice

=item * Tom Hukins

=item * Eric Zylberstejn

=item * David Glasser

=item * Peter Marelas

=item * James William Carlson

=item * Frank D. Cringle

=item * Winfried Koenig

=item * Matthew Wickline

=item * Doug Steinwand

=item * Drew Taylor

=item * Tobias Brox

=item * Michael Lloyd

=item * Simran Gambhir

=item * Chris Houser <chouser@bluweb.com>

=item * Larry Moore

=item * Todd Larason

=item * Jody Biggs

=item * T.J. Mather

=item * Martin Schroth

=item * Dave Wolfe

=item * uchum

=item * Kawai Takanori

=item * Peter Guelich

=item * Chris Nokleberg

=item * Ralph Corderoy

=item * William Ward

=item * Ade Olonoh

=item * Mark Stosberg

=item * Lance Thomas

=item * Roland Giersig

=item * Jere Julian

=item * Peter Leonard

=item * Kenny Smith

=item * Sean P. Scanlon

=item * Martin Pfeffer

=item * David Ferrance

=item * Gyepi Sam  

=item * Darren Chamberlain

=item * Paul Baker

=item * Gabor Szabo

=item * Craig Manley

=item * Richard Fein

=item * The Phalanx Project

=item * Sven Neuhaus

=item * Michael Peters

=item * Jan Dubois

=item * Moritz Lenz

=back

Thanks!

=head1 WEBSITE

You can find information about HTML::Template and other related modules at:

   http://html-template.sourceforge.net

=head1 PUBLIC SUBVERSION SERVER

HTML::Template now has a publicly accessible Subversion server
provided by SourceForge (www.sourceforge.net).  You can access it by
going to http://sourceforge.net/svn/?group_id=1075.  Give it a try!

=head1 AUTHOR

Sam Tregar, C<sam@tregar.com>

=head1 CO-MAINTAINER

Michael Peters, C<mpeters@plusthree.com>

=head1 LICENSE

  HTML::Template : A module for using HTML Templates with Perl
  Copyright (C) 2000-2011 Sam Tregar (sam@tregar.com)

  This module is free software; you can redistribute it and/or modify it
  under the same terms as Perl itself, which means using either:

  a) the GNU General Public License as published by the Free Software
  Foundation; either version 1, or (at your option) any later version,
  
  or

  b) the "Artistic License" which comes with this module.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See either
  the GNU General Public License or the Artistic License for more details.

  You should have received a copy of the Artistic License with this
  module.  If not, I'll be glad to provide one.

  You should have received a copy of the GNU General Public License
  along with this program. If not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA

=cut
libhtml-template-perl 2.10-1 / usr / share / perl5 / HTML / Template.pm
