697 lines
24 KiB
Scheme
697 lines
24 KiB
Scheme
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;;; 9.1: bignum reader
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;;; 9.0: graph marks/refs
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;;;
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(let ()
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(define char-whitespace?
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(lambda (c)
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(or ($char= #\space c)
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(memq ($char->fixnum c) '(9 10 11 12 13)))))
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(define delimiter?
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(lambda (c)
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(or (char-whitespace? c)
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(memq c '(#\( #\) #\[ #\] #\' #\` #\, #\")))))
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(define digit?
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(lambda (c)
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(and ($char<= #\0 c) ($char<= c #\9))))
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(define char->num
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(lambda (c)
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(fx- ($char->fixnum c) ($char->fixnum #\0))))
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(define initial?
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(lambda (c)
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(or (letter? c) (special-initial? c))))
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(define letter?
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(lambda (c)
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(or (and ($char<= #\a c) ($char<= c #\z))
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(and ($char<= #\A c) ($char<= c #\Z)))))
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(define af?
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(lambda (c)
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(or (and ($char<= #\a c) ($char<= c #\f))
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(and ($char<= #\A c) ($char<= c #\F)))))
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(define af->num
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(lambda (c)
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(if (and ($char<= #\a c) ($char<= c #\f))
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(fx+ 10 (fx- ($char->fixnum c) ($char->fixnum #\a)))
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(fx+ 10 (fx- ($char->fixnum c) ($char->fixnum #\A))))))
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(define special-initial?
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(lambda (c)
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(memq c '(#\! #\$ #\% #\& #\* #\/ #\: #\< #\= #\> #\? #\^ #\_ #\~))))
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(define subsequent?
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(lambda (c)
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(or (initial? c) (digit? c) (special-subsequent? c))))
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(define special-subsequent?
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(lambda (c)
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(memq c '(#\+ #\- #\. #\@))))
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(define tokenize-number
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(lambda (n p)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c) n]
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[(digit? c)
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(tokenize-number (+ (* n 10) (char->num c)) p)]
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[(delimiter? c)
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(unread-char c p)
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n]
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[else
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(unread-char c p)
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(error 'tokenize "invalid number syntax: ~a~a" n c)]))))
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(define tokenize-hex
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(lambda (n p)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c) n]
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[(digit? c)
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(tokenize-hex (+ (* n 16) (char->num c)) p)]
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[(af? c)
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(tokenize-hex (+ (* n 16) (af->num c)) p)]
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[(delimiter? c)
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(unread-char c p)
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n]
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[else
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(unread-char c p)
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(error 'tokenize "invalid hex number sequence: ~a~a" n c)]))))
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(define tokenize-hex-init
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(lambda (p)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(unread-char c p)
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(error 'tokenize "invalid #x near end of file")]
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[(digit? c)
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(cons 'datum (tokenize-hex (char->num c) p))]
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[(af? c)
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(cons 'datum (tokenize-hex (af->num c) p))]
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[($char= c #\-)
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(cons 'datum (* -1 (tokenize-hex 0 p)))]
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[($char= c #\+)
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(cons 'datum (tokenize-hex 0 p))]
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[else
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(unread-char c p)
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(error 'tokenize "invalid number syntax: #x~a" c)]))))
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(define tokenize-identifier
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(lambda (ls p)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c) ls]
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[(subsequent? c)
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(tokenize-identifier (cons c ls) p)]
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[(delimiter? c)
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(unread-char c p)
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ls]
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[else
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(unread-char c p)
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(error 'tokenize "invalid identifier syntax: ~a"
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(list->string (reverse (cons c ls))))]))))
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(define tokenize-string
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(lambda (ls p)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(error 'tokenize "end-of-file while inside a string")]
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[($char= #\" c) ls]
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[($char= #\\ c)
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(let ([c (read-char p)])
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(cond
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[($char= #\" c) (tokenize-string (cons #\" ls) p)]
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[($char= #\\ c) (tokenize-string (cons #\\ ls) p)]
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[($char= #\n c) (tokenize-string (cons #\newline ls) p)]
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[($char= #\t c) (tokenize-string (cons #\tab ls) p)]
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[else (error 'tokenize "invalid string escape \\~a" c)]))]
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[else
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(tokenize-string (cons c ls) p)]))))
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(define skip-comment
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(lambda (p)
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(let ([c (read-char p)])
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(unless (eof-object? c)
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(let ([i ($char->fixnum c)])
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(unless (or (fx= i 10) (fx= i 13))
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(skip-comment p)))))))
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(define tokenize-plus
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(lambda (p)
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(let ([c (peek-char p)])
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(cond
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[(eof-object? c) '(datum . +)]
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[(delimiter? c) '(datum . +)]
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[(digit? c)
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(read-char p)
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(cons 'datum (tokenize-number (char->num c) p))]
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[else (error 'tokenize "invalid sequence +~a" c)]))))
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(define tokenize-minus
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(lambda (p)
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(let ([c (peek-char p)])
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(cond
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[(eof-object? c) '(datum . -)]
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[(delimiter? c) '(datum . -)]
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[(digit? c)
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(read-char p)
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(cons 'datum (* -1 (tokenize-number (char->num c) p)))]
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[else (error 'tokenize "invalid sequence -~a" c)]))))
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(define tokenize-dot
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(lambda (p)
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(let ([c (peek-char p)])
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(cond
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[(eof-object? c) 'dot]
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[(delimiter? c) 'dot]
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[($char= c #\.) ; this is second dot
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(read-char p)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(error 'tokenize "invalid syntax .. near end of file")]
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[($char= c #\.) ; this is the third
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(let ([c (peek-char p)])
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(cond
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[(eof-object? c) '(datum . ...)]
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[(delimiter? c) '(datum . ...)]
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[else
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(error 'tokenize "invalid syntax ...~a" c)]))]
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[else
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(unread-char c)
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(error 'tokenize "invalid syntax ..~a" c)]))]
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[else
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(error 'tokenize "invalid syntax .~a" c)]))))
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(define tokenize-char*
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(lambda (i str p d)
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(cond
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[(fx= i (string-length str))
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(let ([c (peek-char p)])
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(cond
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[(eof-object? c) d]
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[(delimiter? c) d]
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[else (error 'tokenize "invalid character after #\\~a" str)]))]
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[else
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(error 'tokenize "invalid eof in the middle of #\\~a" str)]
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[($char= c (string-ref str i))
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(tokenize-char* (fxadd1 i) str p d)]
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[else
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(error 'tokenize
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"invalid char ~a while scanning #\\~a" c str)]))])))
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(define tokenize-char-seq
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(lambda (p str d)
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(let ([c (peek-char p)])
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(cond
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[(eof-object? c) (cons 'datum (string-ref str 0))]
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[(delimiter? c) (cons 'datum (string-ref str 0))]
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[($char= (string-ref str 1) c)
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(read-char p)
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(tokenize-char* 2 str p d)]
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[else (error 'tokenize "invalid syntax near #\\~a~a"
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(string-ref str 0) c)]))))
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(define tokenize-char
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(lambda (p)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(error 'tokenize "invalid #\\ near end of file")]
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[($char= #\s c)
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(tokenize-char-seq p "space" '(datum . #\space))]
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[($char= #\n c)
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(tokenize-char-seq p "newline" '(datum . #\newline))]
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[($char= #\t c)
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(tokenize-char-seq p "tab" '(datum . #\tab))]
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[($char= #\r c)
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(tokenize-char-seq p "return" '(datum . #\return))]
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[else
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(let ([n (peek-char p)])
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(cond
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[(eof-object? n) (cons 'datum c)]
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[(delimiter? n) (cons 'datum c)]
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[else
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(error 'tokenize "invalid syntax #\\~a~a" c n)]))]))))
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(define multiline-error
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(lambda ()
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(error 'tokenize
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"end of file encountered while inside a #|-style comment")))
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(define apprev
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(lambda (str i ac)
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(cond
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[(fx= i (string-length str)) ac]
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[else
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(apprev str (fx+ i 1) (cons (string-ref str i) ac))])))
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(define multiline-comment
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(lambda (p)
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(define f
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(lambda (p ac)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c) (multiline-error)]
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[($char= #\| c)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c) (multiline-error)]
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[($char= #\# c) ac]
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[else (f p (cons c ac))]))]
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[($char= #\# c)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c) (multiline-error)]
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[($char= #\| c)
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(let ([v (multiline-comment p)])
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(if (string? v)
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(f p (apprev v 0 ac))
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(f p ac)))]
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[else
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(f p (cons c (cons #\# ac)))]))]
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[else (f p (cons c ac))]))))
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(let ([ac (f p '())])
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((comment-handler)
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(list->string (reverse ac))))))
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(define read-binary
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(lambda (ac chars p)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c) ac]
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[($char= #\0 c) (read-binary (* ac 2) (cons c chars) p)]
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[($char= #\1 c) (read-binary (+ (* ac 2) 1) (cons c chars) p)]
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[(delimiter? c) (unread-char c p) ac]
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[else
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(unread-char c)
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(error 'tokenize "invalid syntax #b~a"
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(list->string (reverse (cons c chars))))]))))
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(define tokenize-hash
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(lambda (p)
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(tokenize-hash/c (read-char p) p)))
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(define tokenize-hash/c
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(lambda (c p)
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(cond
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[(eof-object? c) (error 'tokenize "invalid # near end of file")]
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[($char= c #\t)
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(let ([c (peek-char p)])
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(cond
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[(eof-object? c) '(datum . #t)]
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[(delimiter? c) '(datum . #t)]
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[else (error 'tokenize "invalid syntax near #t")]))]
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[($char= c #\f)
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(let ([c (peek-char p)])
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(cond
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[(eof-object? c) '(datum . #f)]
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[(delimiter? c) '(datum . #f)]
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[else (error 'tokenize "invalid syntax near #f")]))]
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[($char= #\\ c) (tokenize-char p)]
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[($char= #\( c) 'vparen]
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[($char= #\x c) (tokenize-hex-init p)]
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[($char= #\' c) '(macro . syntax)]
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[($char= #\; c) 'hash-semi]
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[($char= #\% c) '(macro . |#primitive|)]
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[($char= #\| c) (multiline-comment p) (tokenize p)]
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[($char= #\b c)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(error 'tokenize "invalid eof while reading #b")]
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[($char= #\- c)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(error 'tokenize "invalid eof while reading #b-")]
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[($char= #\0 c)
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(cons 'datum
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(* -1 (read-binary 0 '(#\0 #\-) p)))]
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[($char= #\1 c)
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(cons 'datum
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(* -1 (read-binary 1 '(#\1 #\-) p)))]
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[else
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(unread-char c p)
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(error 'tokenize "invalid binary syntax #b-~a" c)]))]
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[($char= #\0 c)
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(cons 'datum (read-binary 0 '(#\0) p))]
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[($char= #\1 c)
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(cons 'datum (read-binary 1 '(#\1) p))]
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[else
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(unread-char c p)
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(error 'tokenize "invalid syntax #b~a" c)]
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))]
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[($char= #\! c)
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(let ([e (read-char p)])
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(when (eof-object? e)
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(error 'tokenize "invalid eof near #!"))
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(unless ($char= #\e e)
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(error 'tokenize "invalid syntax near #!~a" e))
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(let ([o (read-char p)])
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(when (eof-object? o)
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(error 'tokenize "invalid eof near #!e"))
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(unless ($char= #\o o)
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(error 'tokenize "invalid syntax near #!e~a" o))
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(let ([f (read-char p)])
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(when (eof-object? f)
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(error 'tokenize "invalid syntax near #!eo"))
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(unless ($char= #\f f)
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(error 'tokenize "invalid syntax near #!eo~a" f))
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(cons 'datum (eof-object)))))]
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[(digit? c)
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(tokenize-hashnum p (char->num c))]
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[else
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(unread-char c p)
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(error 'tokenize "invalid syntax #~a" c)])))
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(define (tokenize-hashnum p n)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(error 'tokenize "invalid eof inside #n mark/ref")]
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[($char= #\= c) (cons 'mark n)]
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[($char= #\# c) (cons 'ref n)]
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[(digit? c)
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(tokenize-hashnum p (fx+ (fx* n 10) (char->num c)))]
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[else
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(unread-char c p)
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(error 'tokenize "invalid char ~a while inside a #n mark/ref" c)])))
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(define tokenize-bar
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(lambda (p ac)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(error 'tokenize "unexpected eof while reading symbol")]
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[($char= #\\ c)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(error 'tokenize "unexpected eof while reading symbol")]
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[else (tokenize-bar p (cons c ac))]))]
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[($char= #\| c) ac]
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[else (tokenize-bar p (cons c ac))]))))
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(define tokenize/c
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(lambda (c p)
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(cond
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[(eof-object? c) (eof-object)]
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[(char-whitespace? c) (tokenize p)]
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[($char= #\( c) 'lparen]
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[($char= #\) c) 'rparen]
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[($char= #\[ c) 'lbrack]
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[($char= #\] c) 'rbrack]
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[($char= #\' c) '(macro . quote)]
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[($char= #\` c) '(macro . quasiquote)]
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[($char= #\, c)
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(let ([c (peek-char p)])
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(cond
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[(eof-object? c) '(macro . unquote)]
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[($char= c #\@)
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(read-char p)
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'(macro . unquote-splicing)]
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[else '(macro . unquote)]))]
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[($char= #\# c) (tokenize-hash p)]
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[(digit? c)
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(cons 'datum (tokenize-number (char->num c) p))]
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[(initial? c)
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(let ([ls (reverse (tokenize-identifier (cons c '()) p))])
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(cons 'datum (string->symbol (list->string ls))))]
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[($char= #\" c)
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(let ([ls (tokenize-string '() p)])
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(cons 'datum (list->string (reverse ls))))]
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[($char= #\; c)
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(skip-comment p)
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(tokenize p)]
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[($char= #\+ c)
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(tokenize-plus p)]
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[($char= #\- c)
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(tokenize-minus p)]
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[($char= #\. c)
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(tokenize-dot p)]
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[($char= #\| c)
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(let ([ls (reverse (tokenize-bar p '()))])
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(cons 'datum (string->symbol (list->string ls))))]
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[else
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(unread-char c p)
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(error 'tokenize "invalid syntax ~a" c)])))
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(define tokenize
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(lambda (p)
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(tokenize/c (read-char p) p)))
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(define tokenize-initial
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(lambda (p)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c) c]
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[($char= #\# c)
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(let ([c (read-char p)])
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(cond
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[(eof-object? c)
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(error 'tokenize "invalid eof after #")]
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[($char= #\! c)
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(skip-comment p)
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(tokenize p)]
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[else
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(tokenize-hash/c c p)]))]
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[else (tokenize/c c p)]))))
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;;;
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;;;--------------------------------------------------------------* READ *---
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;;;
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(define read-list-rest
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(lambda (p locs k end mis)
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(let ([t (read-token p)])
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(cond
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[(eof-object? t)
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(error 'read "end of file encountered while reading list")]
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[(eq? t end) (values '() locs k)]
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[(eq? t mis)
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(error 'read "paren mismatch")]
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[(eq? t 'dot)
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(let-values ([(d locs k) (read-expr p locs k)])
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(let ([t (read-token p)])
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(cond
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[(eq? t end) (values d locs k)]
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[(eq? t mis)
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(error 'read "paren mismatch")]
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[(eq? t 'dot)
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(error 'read "cannot have two dots in a list")]
|
|
[else
|
|
(error 'read "expecting ~a, got ~a" end t)])))]
|
|
[(eq? t 'hash-semi)
|
|
(let-values ([(ignored locs k) (read-expr p locs k)])
|
|
(read-list-rest p locs k end mis))]
|
|
[else
|
|
(let-values ([(a locs k) (parse-token p locs k t)])
|
|
(let-values ([(d locs k) (read-list-rest p locs k end mis)])
|
|
(let ([x (cons a d)])
|
|
(values x locs
|
|
(if (or (loc? a) (loc? d))
|
|
(extend-k-pair x k)
|
|
k)))))]))))
|
|
(define read-list-init
|
|
(lambda (p locs k end mis)
|
|
(let ([t (read-token p)])
|
|
(cond
|
|
[(eof-object? t)
|
|
(error 'read "end of file encountered while reading list")]
|
|
[(eq? t end) (values '() locs k)]
|
|
[(eq? t mis)
|
|
(error 'read "paren mismatch")]
|
|
[(eq? t 'dot)
|
|
(error 'read "invalid dot while reading list")]
|
|
[(eq? t 'hash-semi)
|
|
(let-values ([(ignored locs k) (read-expr p locs k)])
|
|
(read-list-init p locs k end mis))]
|
|
[else
|
|
(let-values ([(a locs k) (parse-token p locs k t)])
|
|
(let-values ([(d locs k) (read-list-rest p locs k end mis)])
|
|
(let ([x (cons a d)])
|
|
(values x locs
|
|
(if (or (loc? a) (loc? d))
|
|
(extend-k-pair x k)
|
|
k)))))]))))
|
|
(define extend-k-pair
|
|
(lambda (x k)
|
|
(lambda ()
|
|
(let ([a (car x)])
|
|
(when (loc? a)
|
|
(set-car! x (loc-value a))))
|
|
(let ([d (cdr x)])
|
|
(when (loc? d)
|
|
(set-cdr! x (loc-value d))))
|
|
(k))))
|
|
(define vector-put
|
|
(lambda (v k i ls)
|
|
(cond
|
|
[(null? ls) k]
|
|
[else
|
|
(let ([a (car ls)])
|
|
(vector-set! v i a)
|
|
(vector-put v
|
|
(if (loc? a)
|
|
(lambda ()
|
|
(vector-set! v i (loc-value (vector-ref v i)))
|
|
(k))
|
|
k)
|
|
(fxsub1 i) (cdr ls)))])))
|
|
(define read-vector
|
|
(lambda (p locs k count ls)
|
|
(let ([t (read-token p)])
|
|
(cond
|
|
[(eof-object? t)
|
|
(error 'read "end of file encountered while reading a vector")]
|
|
[(eq? t 'rparen)
|
|
(let ([v (make-vector count)])
|
|
(let ([k (vector-put v k (fxsub1 count) ls)])
|
|
(values v locs k)))]
|
|
[(eq? t 'rbrack)
|
|
(error 'read "unexpected ] while reading a vector")]
|
|
[(eq? t 'dot)
|
|
(error 'read "unexpected . while reading a vector")]
|
|
[(eq? t 'hash-semi)
|
|
(let-values ([(ignored locs k) (read-expr p locs k)])
|
|
(read-vector p locs k count ls))]
|
|
[else
|
|
(let-values ([(a locs k) (parse-token p locs k t)])
|
|
(read-vector p locs k (fxadd1 count) (cons a ls)))]))))
|
|
(define-record loc (value set?))
|
|
(define parse-token
|
|
(lambda (p locs k t)
|
|
(cond
|
|
[(eof-object? t) (values (eof-object) locs k)]
|
|
[(eq? t 'lparen) (read-list-init p locs k 'rparen 'rbrack)]
|
|
[(eq? t 'lbrack) (read-list-init p locs k 'rbrack 'rparen)]
|
|
[(eq? t 'vparen) (read-vector p locs k 0 '())]
|
|
[(eq? t 'hash-semi)
|
|
(let-values ([(ignored locs k) (read-expr p locs k)])
|
|
(read-expr p locs k))]
|
|
[(pair? t)
|
|
(cond
|
|
[(eq? (car t) 'datum) (values (cdr t) locs k)]
|
|
[(eq? (car t) 'macro)
|
|
(let-values ([(expr locs k) (read-expr p locs k)])
|
|
(let ([x (list expr)])
|
|
(values (cons (cdr t) x) locs
|
|
(if (loc? expr)
|
|
(lambda ()
|
|
(set-car! x (loc-value expr))
|
|
(k))
|
|
k))))]
|
|
[(eq? (car t) 'mark)
|
|
(let ([n (cdr t)])
|
|
(let-values ([(expr locs k) (read-expr p locs k)])
|
|
(cond
|
|
[(assq n locs) =>
|
|
(lambda (x)
|
|
(let ([loc (cdr x)])
|
|
(when (loc-set? loc)
|
|
(error 'read "duplicate mark ~s" n))
|
|
(set-loc-value! loc expr)
|
|
(set-loc-set?! loc #t)
|
|
(values expr locs k)))]
|
|
[else
|
|
(let ([loc (make-loc expr #t)])
|
|
(let ([locs (cons (cons n loc) locs)])
|
|
(values expr locs k)))])))]
|
|
[(eq? (car t) 'ref)
|
|
(let ([n (cdr t)])
|
|
(cond
|
|
[(assq n locs) =>
|
|
(lambda (x)
|
|
(values (cdr x) locs k))]
|
|
[else
|
|
(let ([loc (make-loc #f #f)])
|
|
(let ([locs (cons (cons n loc) locs)])
|
|
(values loc locs k)))]))]
|
|
[else (error 'read "invalid token! ~s" t)])]
|
|
[else
|
|
(error 'read "unexpected ~s found" t)])))
|
|
|
|
(define read-expr
|
|
(lambda (p locs k)
|
|
(parse-token p locs k (read-token p))))
|
|
|
|
(define read-expr-initial
|
|
(lambda (p locs k)
|
|
(parse-token p locs k (tokenize-initial p))))
|
|
|
|
(define reduce-loc!
|
|
(lambda (x)
|
|
(let ([loc (cdr x)])
|
|
(unless (loc-set? loc)
|
|
(error 'read "referenced mark ~s not set" (car x)))
|
|
(when (loc? (loc-value loc))
|
|
(let f ([h loc] [t loc])
|
|
(if (loc? h)
|
|
(let ([h1 (loc-value h)])
|
|
(if (loc? h1)
|
|
(begin
|
|
(when (eq? h1 t)
|
|
(error 'read "circular marks"))
|
|
(let ([v (f (loc-value h1) (loc-value t))])
|
|
(set-loc-value! h1 v)
|
|
(set-loc-value! h v)
|
|
v))
|
|
(begin
|
|
(set-loc-value! h h1)
|
|
h1)))
|
|
h))))))
|
|
|
|
(define read
|
|
(lambda (p)
|
|
(let-values ([(expr locs k) (read-expr p '() void)])
|
|
(cond
|
|
[(null? locs) expr]
|
|
[else
|
|
(for-each reduce-loc! locs)
|
|
(k)
|
|
(if (loc? expr)
|
|
(loc-value expr)
|
|
expr)]))))
|
|
|
|
(define read-initial
|
|
(lambda (p)
|
|
(let-values ([(expr locs k) (read-expr-initial p '() void)])
|
|
(cond
|
|
[(null? locs) expr]
|
|
[else
|
|
(for-each reduce-loc! locs)
|
|
(k)
|
|
(if (loc? expr)
|
|
(loc-value expr)
|
|
expr)]))))
|
|
|
|
|
|
;;;
|
|
;;;--------------------------------------------------------------* INIT *---
|
|
;;;
|
|
(primitive-set! 'read-token
|
|
(case-lambda
|
|
[() (tokenize (current-input-port))]
|
|
[(p)
|
|
(if (input-port? p)
|
|
(tokenize p)
|
|
(error 'read-token "~s is not an input port" p))]))
|
|
(primitive-set! 'read
|
|
(case-lambda
|
|
[() (read (current-input-port))]
|
|
[(p)
|
|
(if (input-port? p)
|
|
(read p)
|
|
(error 'read "~s is not an input port" p))]))
|
|
(primitive-set! 'comment-handler
|
|
(make-parameter
|
|
(lambda (x) (void))
|
|
(lambda (x)
|
|
(unless (procedure? x)
|
|
(error 'comment-handler "~s is not a procedure" x))
|
|
x)))
|
|
(let ()
|
|
(define read-and-eval
|
|
(lambda (p eval)
|
|
(let ([x (read p)])
|
|
(unless (eof-object? x)
|
|
(eval x)
|
|
(read-and-eval p eval)))))
|
|
|
|
(primitive-set! 'load
|
|
(case-lambda
|
|
[(x) (load x eval)]
|
|
[(x eval)
|
|
(unless (string? x)
|
|
(error 'load "~s is not a string" x))
|
|
(unless (procedure? eval)
|
|
(error 'load "~s is not a procedure" eval))
|
|
(let ([p (open-input-file x)])
|
|
(let ([x (read-initial p)])
|
|
(unless (eof-object? x)
|
|
(eval x)
|
|
(read-and-eval p eval)))
|
|
(close-input-port p))])))
|
|
)
|
|
|