/usr/share/scsh-0.6/env/read-command.scm is in scsh-common-0.6 0.6.7-8.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 | ; Copyright (c) 1993-1999 by Richard Kelsey and Jonathan Rees. See file COPYING.
; Read a command. No command name completion, yet.
(define (read-command prompt form-preferred? i-port)
(really-read-command prompt form-preferred? i-port no-more-commands))
(define (really-read-command prompt form-preferred? i-port more-commands)
(let ((o-port (command-output)))
(let prompt-loop ()
(if (and prompt (not (batch-mode?)))
(display prompt o-port))
(force-output o-port) ;foo
(let loop ()
(let ((c (peek-char i-port)))
(cond ((eof-object? c)
(read-char i-port))
((char-whitespace? c)
(read-char i-port)
(if (char=? c #\newline)
(prompt-loop)
(loop)))
((char=? c #\;) ;Comment
(gobble-line i-port)
(prompt-loop))
((char=? c command-prefix)
(read-char i-port)
(read-named-command i-port more-commands form-preferred?))
((or form-preferred?
(and (not (char-alphabetic? c))
(not (char-numeric? c))
(not (char=? c #\?))))
(read-evaluation-command i-port))
(else
(read-named-command i-port more-commands form-preferred?))))))))
(define (read-command-carefully prompt form-preferred? i-port . more-commands)
(call-with-current-continuation
(lambda (k)
(with-handler
(lambda (c punt)
(cond ((batch-mode?)
(punt))
((or (read-error? c)
(read-command-error? c))
(let ((port (last (condition-stuff c))))
(if (eq? port i-port)
(eat-until-newline i-port))
(display-condition c (command-output))
(k #f)))
((reset-command-input? c)
(k #f))
(else
(punt))))
(lambda ()
(really-read-command prompt form-preferred? i-port
(if (null? more-commands)
no-more-commands
(car more-commands))))))))
(define (eat-until-newline port)
(do ()
((or (not (char-ready? port))
(let ((c (read-char port)))
(or (eof-object? c)
(char=? c #\newline)))))))
(define (read-evaluation-command i-port)
(let ((form (read-form i-port)))
(if (eq? (skip-over horizontal-space? i-port) #\newline)
(read-char i-port))
(make-command 'run (list form))))
(define (no-more-commands name)
#f)
; Read a single form, allowing ## as a way to refer to last command
; output.
(define (read-form port)
(with-sharp-sharp (make-node (get-operator 'quote)
(list 'quote (focus-object)))
(lambda () (read port))))
; Read a command line: <name> <arg> ... <newline>
(define (read-named-command port more-commands form-preferred?)
(let ((c-name (read port)))
(let ((syntax (or (more-commands c-name)
(get-command-syntax c-name))))
(cond (syntax
(make-command c-name
(read-command-arguments syntax #f port
more-commands
form-preferred?)))
(else
(read-command-arguments '(&rest form) #f port #f #f) ; flush junk
(write-line "Unrecognized command name." (command-output))
#f)))))
(define (read-command-arguments ds opt? port more-commands form-preferred?)
(let recur ((ds ds) (opt? opt?))
(let ((c (skip-over horizontal-space? port)))
(cond ((and (not (null? ds))
(eq? (car ds) '&opt))
(recur (cdr ds) #t))
((or (eof-object? c)
(char=? c #\newline)
(if (char=? c #\;) ;Comment
(begin (gobble-line port)
#t)
#f))
(cond ((or (null? ds)
(eq? (car ds) '&rest)
opt?)
(read-char port)
'())
(else
(read-command-error port
"too few command arguments"))))
((null? ds)
(read-command-error port "too many command arguments"))
((eq? (car ds) '&rest)
(let ((arg (read-command-argument (cadr ds) port)))
(cons arg (recur ds #f))))
((eq? (car ds) 'command) ; must be the last argument
(if (not (null? (cdr ds)))
(error "invalid argument descriptions" ds))
(list (really-read-command #f form-preferred? port more-commands)))
(else
(let ((arg (read-command-argument (car ds) port)))
(cons arg (recur (cdr ds) opt?))))))))
(define (read-command-argument d port)
(if (procedure? d)
(d port)
(case d
((filename)
(read-string port char-whitespace?))
((expression form)
(read-form port))
((name)
(let ((thing (read port)))
(if (symbol? thing)
thing
(read-command-error port "invalid name" thing))))
(else (error "invalid argument description" d)))))
(define-condition-type 'read-command-error '(error))
(define read-command-error? (condition-predicate 'read-command-error))
(define (read-command-error port message . rest)
(apply signal 'read-command-error message (append rest (list port))))
; Utilities.
(define (horizontal-space? c)
(and (char-whitespace? c)
(not (char=? c #\newline))))
(define (read-string port delimiter?)
(let loop ((l '()))
(let ((c (peek-char port)))
(cond ((or (eof-object? c)
(delimiter? c))
(list->string (reverse l)))
(else
(loop (cons (read-char port) l)))))))
(define (skip-over pred port)
(let ((c (peek-char port)))
(cond ((eof-object? c) c)
((pred c) (read-char port) (skip-over pred port))
(else c))))
; ## should evaluate to the last REP-loop result.
(define-sharp-macro #\#
(lambda (c port)
(read-char port)
((fluid $sharp-sharp) port)))
(define $sharp-sharp
(make-fluid (lambda (port) (reading-error port "## in invalid context"))))
(define (with-sharp-sharp form body)
(let-fluid $sharp-sharp (lambda (port) form) body))
(define make-command cons) ;(name . args)
; (put 'with-sharp-sharp 'scheme-indent-hook 1)
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