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246 lines
8.5 KiB
Scheme
246 lines
8.5 KiB
Scheme
;; This implements the equivalent of mzscheme's read-syntax for R5RS scheme.
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;; It has not been thoroughly tested. Also it will read an entire file into a
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;; list of syntax objects, instead of returning one syntax object at a time
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;; Everything in this module will be read with case sensitivity.
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#cs
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(module read mzscheme
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(require (lib "lex.ss" "parser-tools")
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(lib "yacc.ss" "parser-tools")
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(lib "readerr.ss" "syntax"))
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(define-tokens data (DATUM))
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(define-empty-tokens delim (OP CP HASHOP QUOTE QUASIQUOTE UNQUOTE UNQUOTE-SPLICING DOT EOF))
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(define scheme-lexer
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(lexer-src-pos
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;; Skip comments, without accumulating extra position information
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[(: (whitespace) (comment)) (return-without-pos (scheme-lexer lex-buf))]
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["#t" (token-DATUM #t)]
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["#f" (token-DATUM #f)]
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[(@ "#\\" (any)) (token-DATUM (caddr (string->list (get-lexeme))))]
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["#\\space" (token-DATUM #\space)]
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["#\\newline" (token-DATUM #\newline)]
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[(: (@ (initial) (* (subsequent))) + - "...") (token-DATUM (string->symbol (get-lexeme)))]
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[#\" (token-DATUM (list->string (get-string-token lex-buf)))]
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[#\( 'OP]
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[#\) 'CP]
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[#\[ 'OP]
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[#\] 'CP]
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["#(" 'HASHOP]
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[(num2) (token-DATUM (string->number (get-lexeme) 2))]
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[(num8) (token-DATUM (string->number (get-lexeme) 8))]
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[(num10) (token-DATUM (string->number (get-lexeme) 10))]
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[(num16) (token-DATUM (string->number (get-lexeme) 16))]
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["'" 'QUOTE]
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["`" 'QUASIQUOTE]
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["," 'UNQUOTE]
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[",@" 'UNQUOTE-SPLICING]
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["." 'DOT]
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[(eof) 'EOF]))
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(define get-string-token
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(lexer
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[(^ #\" #\\) (cons (car (string->list (get-lexeme)))
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(get-string-token lex-buf))]
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[(@ #\\ #\\) (cons #\\ (get-string-token lex-buf))]
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[(@ #\\ #\") (cons #\" (get-string-token lex-buf))]
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[#\" null]))
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(define-lex-abbrevs
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[any (- #\000 #\377)]
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[letter (: (- a z) (- A Z))]
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[digit (- #\0 #\9)]
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[whitespace (: #\newline #\return #\tab #\space #\vtab)]
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[initial (: (letter) ! $ % & * / : < = > ? ^ _ ~)]
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[subsequent (: (initial) (digit) + - #\. @)]
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[comment (@ #\; (* (^ #\newline)) #\newline)]
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; [numR (@ (prefixR) (complexR))]
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; [complexR (: (realR)
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; (@ (realR) @ (realR))
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; (@ (realR) + (urealR) i)
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; (@ (realR) - (urealR) i)
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; (@ (realR) + i)
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; (@ (realR) - i)
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; (@ + (urealR) i)
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; (@ - (urealR) i)
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; (@ + i)
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; (@ - i))]
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; [realR (@ (sign) (urealR))]
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; [urealR (: (uintegerR) (@ (uintegerR) / (uintegerR)) (decimalR))]
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; [uintegerR (@ (+ (digitR)) (* #\#))]
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; [prefixR (: (@ (radixR) (exactness))
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; (@ (exactness) (radixR)))]
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; [numR (@ (prefixR) (complexR))]
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; [complexR (: (realR)
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; (@ (realR) @ (realR))
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[num2 (@ (prefix2) (complex2))]
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[complex2 (: (real2)
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(@ (real2) @ (real2))
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(@ (real2) + (ureal2) i)
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(@ (real2) - (ureal2) i)
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(@ (real2) + i)
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(@ (real2) - i)
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(@ + (ureal2) i)
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(@ - (ureal2) i)
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(@ + i)
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(@ - i))]
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[real2 (@ (sign) (ureal2))]
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[ureal2 (: (uinteger2) (@ (uinteger2) / (uinteger2)))]
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[uinteger2 (@ (+ (digit2)) (* #\#))]
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[prefix2 (: (@ (radix2) (exactness))
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(@ (exactness) (radix2)))]
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[radix2 "#b"]
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[digit2 (: #\0 #\1)]
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[num8 (@ (prefix8) (complex8))]
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[complex8 (: (real8)
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(@ (real8) @ (real8))
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(@ (real8) + (ureal8) i)
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(@ (real8) - (ureal8) i)
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(@ (real8) + i)
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(@ (real8) - i)
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(@ + (ureal8) i)
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(@ - (ureal8) i)
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(@ + i)
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(@ - i))]
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[real8 (@ (sign) (ureal8))]
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[ureal8 (: (uinteger8) (@ (uinteger8) / (uinteger8)))]
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[uinteger8 (@ (+ (digit8)) (* #\#))]
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[prefix8 (: (@ (radix8) (exactness))
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(@ (exactness) (radix8)))]
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[radix8 "#o"]
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[digit8 (- #\0 #\7)]
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[num10 (@ (prefix10) (complex10))]
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[complex10 (: (real10)
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(@ (real10) @ (real10))
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(@ (real10) + (ureal10) i)
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(@ (real10) - (ureal10) i)
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(@ (real10) + i)
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(@ (real10) - i)
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(@ + (ureal10) i)
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(@ - (ureal10) i)
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(@ + i)
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(@ - i))]
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[real10 (@ (sign) (ureal10))]
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[ureal10 (: (uinteger10) (@ (uinteger10) / (uinteger10)) (decimal10))]
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[uinteger10 (@ (+ (digit10)) (* #\#))]
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[prefix10 (: (@ (radix10) (exactness))
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(@ (exactness) (radix10)))]
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[radix10 (: (@) "#d")]
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[digit10 (digit)]
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[decimal10 (: (@ (uinteger10) (suffix))
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(@ #\. (+ (digit10)) (* #\#) (suffix))
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(@ (+ (digit10)) #\. (* (digit10)) (* #\#) (suffix))
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(@ (+ (digit10)) (+ #\#) #\. (* #\#) (suffix)))]
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[num16 (@ (prefix16) (complex16))]
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[complex16 (: (real16)
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(@ (real16) @ (real16))
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(@ (real16) + (ureal16) i)
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(@ (real16) - (ureal16) i)
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(@ (real16) + i)
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(@ (real16) - i)
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(@ + (ureal16) i)
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(@ - (ureal16) i)
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(@ + i)
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(@ - i))]
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[real16 (@ (sign) (ureal16))]
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[ureal16 (: (uinteger16) (@ (uinteger16) / (uinteger16)))]
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[uinteger16 (@ (+ (digit16)) (* #\#))]
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[prefix16 (: (@ (radix16) (exactness))
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(@ (exactness) (radix16)))]
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[radix16 "#x"]
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[digit16 (: (digit) (- #\a #\f) (- #\A #\F))]
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[suffix (: (@) (@ (exponent-marker) (sign) (+ (digit10))))]
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[exponent-marker (: e s f d l)]
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[sign (: (@) + -)]
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[exactness (: (@) "#i" "#e")])
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(define stx-for-original-property (read-syntax #f (open-input-string "original")))
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;; A macro to build the syntax object
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(define-syntax (build-so stx)
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(syntax-case stx ()
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((_ value start end)
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(with-syntax ((start-pos (datum->syntax-object
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(syntax end)
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(string->symbol
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(format "$~a-start-pos"
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(syntax-object->datum (syntax start))))))
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(end-pos (datum->syntax-object
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(syntax end)
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(string->symbol
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(format "$~a-end-pos"
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(syntax-object->datum (syntax end))))))
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(source (datum->syntax-object
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(syntax end)
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'source-name)))
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(syntax
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(datum->syntax-object
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#f
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value
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(list source
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(position-line start-pos)
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(position-col start-pos)
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(position-offset start-pos)
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(- (position-offset end-pos)
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(position-offset start-pos)))
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stx-for-original-property))))))
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(define (scheme-parser source-name)
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(parser
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(src-pos)
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(start s)
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(end EOF)
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(error (lambda (a name val start end)
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(raise-read-error
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"read-error"
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source-name
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(position-line start)
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(position-col start)
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(position-offset start)
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(- (position-offset end)
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(position-offset start)))))
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(tokens data delim)
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(grammar
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(s [(sexp-list) (reverse $1)])
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(sexp [(DATUM) (build-so $1 1 1)]
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[(OP sexp-list CP) (build-so (reverse $2) 1 3)]
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[(HASHOP sexp-list CP) (build-so (list->vector (reverse $2)) 1 3)]
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[(QUOTE sexp) (build-so (list 'quote $2) 1 2)]
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[(QUASIQUOTE sexp) (build-so (list 'quasiquote $2) 1 2)]
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[(UNQUOTE sexp) (build-so (list 'unquote $2) 1 2)]
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[(UNQUOTE-SPLICING sexp) (build-so (list 'unquote-splicing $2) 1 2)]
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[(OP sexp-list DOT sexp CP) (build-so (append (reverse $2) $4) 1 5)])
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(sexp-list [() null]
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[(sexp-list sexp) (cons $2 $1)]))))
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(define (rs sn ip off)
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(let ((lb (make-lex-buf ip off)))
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((scheme-parser sn) (lambda () (scheme-lexer lb)))))
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(define readsyntax
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(case-lambda ((sn) (rs sn (current-input-port) (list 0 0 0)))
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((sn ip) (rs sn ip (list 0 0 0)))
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((sn ip off) (rs sn ip off))))
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(provide (rename readsyntax read-syntax))
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) |