/usr/share/racket/pkgs/algol60/parse.rkt is in racket-common 6.7-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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(require parser-tools/lex
(prefix-in : parser-tools/lex-sre)
"cfg-parser.rkt"
parser-tools/yacc
syntax/readerr
"prims.rkt")
(provide parse-a60-file parse-a60-port)
(define-lex-abbrevs [lex:letter (:or (:/ #\a #\z) (:/ #\A #\Z))]
[lex:digit (:/ #\0 #\9)]
[lex:whitespace (:or #\newline #\return #\tab #\space #\vtab)]
[lex:comment (:: (:* lex:whitespace) "comment" (:* (:~ #\;)) #\;)])
(define-tokens non-terminals (<logical-value>
<type> <identifier>
<unsigned-integer> <unsigned-float> <string>
GOTO IF THEN ELSE FOR DO STEP UNTIL WHILE
OWN ARRAY STRING PROCEDURE SWITCH LABEL VALUE
BEGIN END
POWER PLUS MINUS TIMES SLASH DIVIDE
LESS LESS-OR-EQUAL EQUAL GREATER-OR-EQUAL GREATER NOT-EQUAL ASSIGN
NEGATE AND OR IMPLIES EQUIV
COMMA COLON SEMICOLON
OPEN CLOSE OPENSQ CLOSESQ
EOF
UNPARSEABLE))
(define stx-for-original-property (read-syntax #f (open-input-string "original")))
(define-syntax (token stx)
(syntax-case stx ()
[(_ name val)
(identifier? (syntax name))
(let ([name (syntax name)])
(with-syntax ([token-name (datum->syntax
name
(string->symbol
(format "token-~a" (syntax-e name))))]
[source-name (datum->syntax name 'source-name)]
[start-pos (datum->syntax name 'start-pos)]
[end-pos (datum->syntax name 'end-pos)])
(syntax
(token-name
(datum->syntax #f val
(list
source-name
(position-line start-pos)
(position-col start-pos)
(position-offset start-pos)
(- (position-offset end-pos)
(position-offset start-pos)))
stx-for-original-property)))))]))
(define-syntax (ttoken stx)
(syntax-case stx ()
[(_ name)
(identifier? (syntax name))
(syntax (token name 'name))]))
(define (lex source-name)
(lexer
[(:+ lex:whitespace) (void)]
["true" (token <logical-value> #t)]
["false" (token <logical-value> #f)]
["real" (token <type> 'real)]
["integer" (token <type> 'integer)]
["Boolean" (token <type> 'boolean)]
["goto" (ttoken GOTO)]
["if" (ttoken IF)]
["then" (ttoken THEN)]
["else" (ttoken ELSE)]
["for" (ttoken FOR)]
["do" (ttoken DO)]
["step" (ttoken STEP)]
["until" (ttoken UNTIL)]
["while" (ttoken WHILE)]
["own" (ttoken OWN)]
["array" (ttoken ARRAY)]
["string" (ttoken STRING)]
["procedure" (ttoken PROCEDURE)]
["switch" (ttoken SWITCH)]
["label" (ttoken LABEL)]
["value" (ttoken VALUE)]
[(:: "begin" lex:comment) (ttoken BEGIN)]
["begin" (ttoken BEGIN)]
[(:: "end" lex:comment) (ttoken BEGIN)]
["end" (ttoken END)]
["^" (token POWER 'expt)]
["+" (token PLUS '+)]
["-" (token MINUS '-)]
["*" (token TIMES '*)]
["/" (token SLASH '/)]
["div" (token DIVIDE 'quotient)]
["<" (token LESS '<)]
["<=" (token LESS-OR-EQUAL '<=)]
["=" (token EQUAL '=)]
[">" (token GREATER '>)]
[">=" (token GREATER-OR-EQUAL '>=)]
["!=" (token NOT-EQUAL '!=)]
["!" (token NEGATE '!)]
["&" (token AND '&)]
["|" (token OR '\|)]
["=>" (token IMPLIES '==>)]
["==" (token EQUIV '==)]
[":=" (ttoken ASSIGN)]
["," (ttoken COMMA)]
[":" (ttoken COLON)]
[(:: ";" lex:comment) (ttoken SEMICOLON)]
[";" (ttoken SEMICOLON)]
["(" (ttoken OPEN)]
[")" (ttoken CLOSE)]
["[" (ttoken OPENSQ)]
["]" (ttoken CLOSESQ)]
[(:: lex:letter (:* (:or lex:letter lex:digit))) (token <identifier> (string->symbol lexeme))]
[(:+ lex:digit) (token <unsigned-integer> (string->number lexeme))]
[(:or (:: (:+ lex:digit) #\. (:* lex:digit))
(:: (:* lex:digit) #\. (:+ lex:digit))) (token <unsigned-float> (string->number lexeme))]
[(:: #\` (:* (:~ #\' #\`)) #\') (let ([s lexeme])
(token <string> (substring s 1 (sub1 (string-length s)))))]
[(eof) (ttoken EOF)]
[any-char (token UNPARSEABLE (string->symbol lexeme))]))
(define parse
(cfg-parser
(tokens non-terminals)
(start <program>)
(end EOF)
(error (lambda (_ name stx start end)
(raise-read-error (format "parse error near ~a" name)
(syntax-source stx)
(syntax-line stx)
(syntax-column stx)
(syntax-position stx)
(syntax-span stx))))
(suppress)
(grammar
;; ==================== Expressions ====================
(<expression> [(<arithmetic-expression>) $1]
[(<Boolean-expression>) $1]
[(<designational-expression>) $1])
;; -------------------- Numbers --------------------
(<arithmetic-expression> [(<simple-arithmetic-expression>) $1]
[(IF <Boolean-expression>
THEN <simple-arithmetic-expression>
ELSE <arithmetic-expression>)
(make-a60:if $2 $4 $6)])
(<simple-arithmetic-expression> [(<term>) $1]
[(<adding-operator> <term>) (make-a60:unary 'num 'num $1 $2)]
[(<simple-arithmetic-expression> <adding-operator> <term>)
(make-a60:binary 'num 'num $2 $1 $3)])
(<term> [(<factor>) $1]
[(<term> <multiplying-operator> <factor>) (make-a60:binary 'num 'num $2 $1 $3)])
(<factor> [(<primary>) $1]
[(<factor> POWER <primary>) (make-a60:binary 'num 'num $2 $1 $3)])
(<adding-operator> [(PLUS) $1]
[(MINUS) $1])
(<multiplying-operator> [(TIMES) $1]
[(SLASH) $1]
[(DIVIDE) $1])
(<primary> [(<unsigned-integer>) $1]
[(<unsigned-float>) $1]
[(<variable>) $1]
[(<function-designator>) $1]
[(OPEN <arithmetic-expression> CLOSE) $2])
;; -------------------- Booleans --------------------
(<relational-operator> [(LESS) $1]
[(LESS-OR-EQUAL) $1]
[(EQUAL) $1]
[(GREATER-OR-EQUAL) $1]
[(GREATER) $1]
[(NOT-EQUAL) $1])
(<relation> [(<simple-arithmetic-expression> <relational-operator> <simple-arithmetic-expression>)
(make-a60:binary 'bool 'num $2 $1 $3)])
(<Boolean-primary> [(<logical-value>) $1]
[(<variable>) $1]
[(<function-designator>) $1]
[(<relation>) $1]
[(OPEN <Boolean-expression> CLOSE) $2])
(<Boolean-secondary> [(<Boolean-primary>) $1]
[(NEGATE <Boolean-primary>) (make-a60:unary 'bool 'bool $1 $2)])
(<Boolean-factor> [(<Boolean-secondary>) $1]
[(<Boolean-factor> AND <Boolean-secondary>) (make-a60:binary 'bool 'bool $2 $1 $3)])
(<Boolean-term> [(<Boolean-factor>) $1]
[(<Boolean-term> OR <Boolean-factor>) (make-a60:binary 'bool 'bool $2 $1 $3)])
(<implication> [(<Boolean-term>) $1]
[(<implication> IMPLIES <Boolean-term>) (make-a60:binary 'bool 'bool $2 $1 $3)])
(<simple-Boolean> [(<implication>) $1]
[(<simple-Boolean> EQUIV <implication>) (make-a60:binary 'bool 'bool $2 $1 $3)])
(<Boolean-expression> [(<simple-Boolean>) $1]
[(IF <Boolean-expression>
THEN <simple-Boolean>
ELSE <Boolean-expression>)
(make-a60:if $2 $4 $6)])
;; -------------------- Designationals --------------------
(<label> [(<identifier>) $1]
[(<unsigned-integer>) $1])
(<switch-identifier> [(<identifier>) $1])
(<switch-designator> [(<switch-identifier> OPENSQ <arithmetic-expression> CLOSESQ)
(make-a60:subscript $1 $3)])
(<simple-designational-expression> [(<label>) $1]
[(<switch-designator>) $1]
[(OPEN <designational-expression> CLOSE) $2])
(<designational-expression> [(<simple-designational-expression>) $1]
[(IF <Boolean-expression>
THEN <simple-designational-expression>
ELSE <designational-expression>)
(make-a60:if $2 $4 $6)])
;; -------------------- Variables --------------------
(<subscript-list> [(<arithmetic-expression>) (list $1)]
[(<subscript-list> COMMA <arithmetic-expression>) (append $1 (list $3))])
(<subscripted-variable> [(<identifier> OPENSQ <subscript-list> CLOSESQ) (make-a60:variable $1 $3)])
(<variable> [(<identifier>) (make-a60:variable $1 null)]
[(<subscripted-variable>) $1])
;; -------------------- Function calls --------------------
(<function-designator> [(<identifier> <actual-parameter-part>) (make-a60:app $1 $2)])
;; ==================== Statements ====================
;; - - - - - - - - - - non-empty - - - - - - - - - -
(<unlabelled-basic-nonempty-statement> [(<assignment-statement>) $1]
[(<go-to-statement>) $1]
[(<procedure-statement>) $1])
(<basic-nonempty-statement> [(<unlabelled-basic-nonempty-statement>) $1]
[(<label> COLON <basic-statement>) (make-a60:label $1 $3)])
(<unconditional-nonempty-statement> [(<basic-nonempty-statement>) $1]
[(<compound-statement>) $1]
[(<block>) $1])
(<nonempty-statement> [(<unconditional-nonempty-statement>) $1]
[(<conditional-statement>) $1]
[(<for-statement>) $1])
;; - - - - - - - - - - possibly empty - - - - - - - - - -
(<unlabelled-basic-statement> [(<unlabelled-basic-nonempty-statement>) $1]
[(<dummy-statement>) $1])
(<basic-statement> [(<unlabelled-basic-statement>) $1]
[(<label> COLON <basic-statement>) (make-a60:label $1 $3)])
(<unconditional-statement> [(<basic-statement>) $1]
[(<unconditional-nonempty-statement>) $1])
(<statement> [(<unconditional-statement>) $1]
[(<nonempty-statement>) $1])
;; -------------------- block and compound --------------------
(<compound-tail> [(<statement> END) (list $1)]
[(<statement> SEMICOLON <compound-tail>) (cons $1 $3)])
(<block-head> [(BEGIN <declaration>) (list $2)]
[(<block-head> SEMICOLON <declaration>) (append $1 (list $3))])
(<unlabelled-block> [(<block-head> SEMICOLON <compound-tail>) (make-a60:block $1 $3)])
(<unlabelled-compound> [(BEGIN <compound-tail>) (make-a60:compound $2)])
(<compound-statement> [(<unlabelled-compound>) $1]
[(<label> COLON <compound-statement>) (make-a60:label $1 $3)])
(<block> [(<unlabelled-block>) $1]
[(<label> COLON <block>) (make-a60:label $1 $3)])
;; -------------------- assignment --------------------
(<left-part> [(<variable> ASSIGN) $1])
(<left-part-list> [(<left-part>) (list $1)]
[(<left-part-list> <left-part>) (append $1 (list $2))])
(<assignment-statement> [(<left-part-list> <arithmetic-expression>) (make-a60:assign $1 $2)]
[(<left-part-list> <Boolean-expression>) (make-a60:assign $1 $2)])
;; -------------------- goto --------------------
(<go-to-statement> [(GOTO <designational-expression>) (make-a60:goto $2)])
;; -------------------- dummy --------------------
(<dummy-statement> [() (make-a60:compound null)])
;; -------------------- conditional --------------------
(<conditional-statement> [(IF <Boolean-expression> THEN <unconditional-statement>)
(make-a60:branch $2 $4 (make-a60:compound null))]
[(IF <Boolean-expression> THEN <unconditional-statement> ELSE <statement>)
(make-a60:branch $2 $4 $6)]
[(IF <Boolean-expression> THEN <for-statement>)
(make-a60:branch $2 $4 (make-a60:compound null))]
[(<label> COLON <conditional-statement>) (make-a60:label $1 $3)])
;; -------------------- for --------------------
(<for-list-element> [(<arithmetic-expression>) (make-a60:for-number $1)]
[(<arithmetic-expression> STEP <arithmetic-expression> UNTIL <arithmetic-expression>)
(make-a60:for-step $1 $3 $5)]
[(<arithmetic-expression> WHILE <Boolean-expression>) (make-a60:for-while $1 $3)])
(<for-list> [(<for-list-element>) (list $1)]
[(<for-list> COMMA <for-list-element>) (append $1 (list $3))])
(<for-statement> [(FOR <variable> ASSIGN <for-list> DO <statement>)
(make-a60:for $2 $4 $6)]
[(<label> COLON <for-statement>) (make-a60:label $1 $3)])
;; -------------------- procedure statement --------------------
(<actual-parameter> [(<string>) $1]
[(<expression>) $1]
; [(<identifier>) $1] ; switch, array, or procedure
)
(<parameter-delimiter> [(COMMA) (void)]
[(CLOSE <identifier> COLON OPEN) (void)]) ;; <identifier> was <letter-string>!
(<actual-parameter-list> [(<actual-parameter>) (list $1)]
[(<actual-parameter-list> <parameter-delimiter> <actual-parameter>)
(append $1 (list $3))])
(<actual-parameter-part> [() null]
[(OPEN <actual-parameter-list> CLOSE) $2])
(<procedure-statement> [(<identifier> <actual-parameter-part>) (make-a60:call $1 $2)])
;; ==================== Declarations ====================
(<declaration> [(<type-declaration>) $1]
[(<array-declaration>) $1]
[(<switch-declaration>) $1]
[(<procedure-declaration>) $1])
;; -------------------- Simple --------------------
(<type-list> [(<identifier>) (list $1)]
[(<identifier> COMMA <type-list>) (cons $1 $3)])
(<local-or-own-type> [(<type>) $1]
[(OWN <type>) (box $2)]) ; box => own
(<type-declaration> [(<local-or-own-type> <type-list>) (make-a60:type-decl $1 $2)])
;; -------------------- Arrays --------------------
(<bound-pair> [(<arithmetic-expression> COLON <arithmetic-expression>) (cons $1 $3)])
(<bound-pair-list> [(<bound-pair>) (list $1)]
[(<bound-pair-list> COMMA <bound-pair>) (append $1 (list $3))])
(<array-segment> [(<identifier> OPENSQ <bound-pair-list> CLOSESQ) (list (cons $1 $3))]
[(<identifier> COMMA <array-segment>) (cons (cons $1 (cdar $3)) $3)])
(<array-list> [(<array-segment>) $1]
[(<array-list> COMMA <array-segment>) (append $1 $3)])
(<array-declaration> [(ARRAY <array-list>) (make-a60:array-decl #'unknown $2)]
[(<local-or-own-type> ARRAY <array-list>) (make-a60:array-decl $1 $3)])
;; -------------------- Switches --------------------
(<switch-list> [(<designational-expression>) (list $1)]
[(<switch-list> COMMA <designational-expression>) (append $1 (list $3))])
(<switch-declaration> [(SWITCH <switch-identifier> ASSIGN <switch-list>) (make-a60:switch-decl $2 $4)])
;; -------------------- Procedures --------------------
(<formal-parameter> [(<identifier>) $1])
(<formal-parameter-list> [(<formal-parameter>) (list $1)]
[(<formal-parameter-list> <parameter-delimiter> <formal-parameter>)
(append $1 (list $3))])
(<formal-parameter-part> [() null]
[(OPEN <formal-parameter-list> CLOSE) $2])
(<identifier-list> [(<identifier>) (list $1)]
[(<identifier-list> COMMA <identifier>) (append $1 (list $3))])
(<value-part> [(VALUE <identifier-list> SEMICOLON) $2]
[() null])
(<specifier> [(STRING) 'string]
[(<type>) $1]
[(ARRAY) '(array #'unknown)]
[(<type> ARRAY) `(array ,$1)]
[(LABEL) 'label]
[(SWITCH) 'switch]
[(PROCEDURE) '(procedure #'unknown)]
[(<type> PROCEDURE) `(procedure ,$1)])
(<nonempty-specification-part> [(<specifier> <identifier-list> SEMICOLON) (list (cons $1 $2))]
[(<nonempty-specification-part> <specifier> <identifier-list> SEMICOLON)
(append $1 (list (cons $2 $3)))])
(<specification-part> [() null]
[(<nonempty-specification-part>) $1])
(<procedure-heading> [(<identifier> <formal-parameter-part> SEMICOLON <value-part> <specification-part>)
(list $1 $2 $4 $5)])
(<procedure-body> [(<nonempty-statement>) $1])
(<procedure-declaration> [(PROCEDURE <procedure-heading> <procedure-body>)
(make-a60:proc-decl #'unknown (car $2) (cadr $2) (caddr $2) (cadddr $2) $3)]
[(<type> PROCEDURE <procedure-heading> <procedure-body>)
(make-a60:proc-decl $1 (car $3) (cadr $3) (caddr $3) (cadddr $3) $4)])
;; ==================== Program ====================
(<program> [(<block>) $1]
[(<compound-statement>) $1]))))
(define-syntax (define-a60-structs stx)
(syntax-case stx ()
[(_ (struct-name (field ...)) ...)
(with-syntax ([(a60:struct ...) (map (lambda (id)
(datum->syntax
id
(string->symbol
(format "a60:~a" (syntax-e id)))))
(syntax->list (syntax (struct-name ...))))])
(syntax (begin (define-struct a60:struct (field ...)) ...
(provide (struct-out a60:struct) ...))))]))
(define-a60-structs
;; Expressions
(if (test then else))
(unary (type argtype op arg))
(binary (type argtype op arg1 arg2))
(subscript (array index))
(variable (name indices))
(app (func args))
;; plus numbers, strings, and booleans
;; Statements
(block (decls statements))
(compound (statements))
(assign (variables rhs))
(goto (target))
(branch (test then else))
(call (proc args))
(for (variable values body))
(dummy ())
(label (name statement))
;; for values
(for-number (value))
(for-step (start step end))
(for-while (value test))
;; declarations
(type-decl (type vars))
(array-decl (type vars))
(switch-decl (var cases))
(proc-decl (result-type var arg-vars by-value-vars arg-specs body)))
(define (parse-a60-port port file)
(let ([lexer (lex file)])
(port-count-lines! port)
(parse
(lambda ()
(let loop ()
(let ([v (lexer port)])
(if (void? v)
(loop)
v)))))))
(define (parse-a60-file file)
(with-input-from-file file
(lambda ()
(parse-a60-port (current-input-port)
(path->complete-path file)))))
|