scsh-0.6/ps-compiler/prescheme/unused/track-read.scm

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1999-09-14 08:45:02 -04:00
; -*- Mode: Scheme; Syntax: Scheme; Package: Scheme; -*-
; Copyright (c) 1994 by Richard Kelsey. See file COPYING.
; Scheme48 reader modified to annotate pairs with source line and column
; data.
(define-record-type annotation
(
file
row
column
)
(form
))
(define $current-annotating-port (make-fluid #f))
(define-syntax define-lap
(lambda (exp rename compare)
(let ((spec (cadr exp))
(stuff (cddr exp)))
`(define ,(car spec) (lap ,spec . ,stuff)))))
(define-lap (annotated-cons car cdr annotation)
(check-nargs= 3)
(pop)
(make-stored-object 3 pair)
(return))
(define (file-annotated-cons car cdr row column)
(let* ((note (annotation-maker (fluid $current-annotating-port)
row
column))
(pair (annotated-cons car cdr note)))
(set-annotation-form! note pair)
(make-immutable! note)
(make-immutable! pair)
pair))
(define-lap (pair-annotation pair)
(check-nargs= 1)
(make-env 1)
(local pair)
(stored-object-length pair)
(push)
(literal 3)
(=)
(jump-if-false lose)
(local pair)
(stored-object-ref pair 2) ; this is the reason for the LAP
(return)
lose
(false)
(return))
; A little Scheme reader.
; Nonstandard things needed:
; char->ascii, ascii->char (for dispatch table)
; make-fluid, fluid (used only to implement ##)
; reverse-list->string (ok to define as list->string of reverse)
; really-string->symbol (ok to define this to be string->symbol)
(define preferred-case
(if (char=? (string-ref (symbol->string 't) 0) #\T)
char-upcase
char-downcase))
(define close-paren (list 'close-paren))
(define dot (string->symbol "."))
(define (read-and-annotate port id)
(let-fluid $current-annotating-port id
(lambda ()
(let loop ()
(let ((form (sub-read port)))
(cond ((eq? form dot)
(error "\" . \" in illegal context"))
((eq? form close-paren)
;; Too many right parens.
(loop))
(else form)))))))
(define (sub-read-carefully port)
(let ((form (sub-read port)))
(cond ((eof-object? form)
(error "unexpected end of file"))
((eq? form close-paren)
(error "unexpected right parenthesis"))
((eq? form dot)
(error "unexpected \" . \""))
(else form))))
; Main dispatch
(define (sub-read port)
(let ((c (read-char port)))
(if (eof-object? c)
c
((vector-ref read-dispatch-vector (char->ascii c))
c port))))
(define read-dispatch-vector
(make-vector 256
(lambda (c port)
(error "illegal character read" c))))
(define read-terminating?-vector
(make-vector 256 #t))
(define (set-standard-syntax! char terminating? reader)
(vector-set! read-dispatch-vector (char->ascii char) reader)
(vector-set! read-terminating?-vector (char->ascii char) terminating?))
(let ((sub-read-whitespace
(lambda (c port)
c ;ignored
(sub-read port))))
(do ((i 0 (+ i 1)))
((>= i (vector-length read-dispatch-vector)))
(if (char-whitespace? (ascii->char i))
(vector-set! read-dispatch-vector i sub-read-whitespace))))
(let ((sub-read-constituent
(lambda (c port)
(parse-token (sub-read-token c port)))))
(for-each (lambda (c)
(set-standard-syntax! c #f sub-read-constituent))
(string->list
(string-append "!$%&*+-./0123456789:<=>?@^_~ABCDEFGHIJKLM"
"NOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"))))
; Usual read macros
(define (set-standard-read-macro! c terminating? proc)
(set-standard-syntax! c terminating? proc))
(define (sub-read-list c port)
(let* ((row (current-row port))
(column (- (current-column port) 1)) ; to get the location of "("
(form (sub-read port)))
(cond ((eof-object? form)
(error "end of file inside list -- unbalanced parentheses"))
((eq? form close-paren) '())
((eq? form dot)
(let* ((last-form (sub-read-carefully port))
(another-form (sub-read port)))
(cond ((eq? another-form close-paren)
last-form)
(else
(error "randomness after form after dot" another-form)))))
(else
(file-annotated-cons form (sub-read-list c port) row column)))))
(set-standard-read-macro! #\( #t sub-read-list)
(set-standard-read-macro! #\) #t
(lambda (c port)
c port
close-paren))
(set-standard-read-macro! #\' #t
(lambda (c port)
c
(list 'quote (sub-read-carefully port))))
(set-standard-read-macro! #\` #t
(lambda (c port)
c
(list 'quasiquote (sub-read-carefully port))))
(set-standard-read-macro! #\, #t
(lambda (c port)
c
;; Do not beta-reduce this!
(let* ((next (peek-char port))
(marker (cond ((eof-object? next)
(error "end of file after ,"))
((char=? next #\@)
(read-char port)
'unquote-splicing)
(else 'unquote))))
(list marker
(sub-read-carefully port)))))
(set-standard-read-macro! #\" #t
(lambda (c port)
c ;ignored
(let loop ((l '()) (i 0))
(let ((c (read-char port)))
(cond ((eof-object? c)
(error "end of file within a string"))
((char=? c #\\)
(let ((c (read-char port)))
(cond ((eof-object? c)
(error "end of file within a string"))
((or (char=? c #\\) (char=? c #\"))
(loop (cons c l) (+ i 1)))
(else
(error "invalid escaped character in string" c)))))
((char=? c #\")
(reverse-list->string l i))
(else
(loop (cons c l) (+ i 1))))))))
(set-standard-read-macro! #\; #t
(lambda (c port)
c ;ignored
(gobble-line port)
(sub-read port)))
(define (gobble-line port)
(let loop ()
(let ((c (read-char port)))
(cond ((eof-object? c) c)
((char=? c #\newline) #f)
(else (loop))))))
(set-standard-read-macro! #\# #f
(lambda (c port)
c ;ignored
(let* ((c (peek-char port))
(c (if (eof-object? c)
(error "end of file after #")
(char-downcase c))))
(cond ((char=? c #\f) (read-char port) #f)
((char=? c #\t) (read-char port) #t)
((char=? c #\\)
(read-char port)
(let ((c (peek-char port)))
(cond ((eof-object? c)
(error "end of file after #\\"))
((char-alphabetic? c)
(let ((name (sub-read-carefully port)))
(cond ((= (string-length (symbol->string name)) 1)
c)
((assq name '((space #\space)
(newline #\newline)))
=> cadr)
(else
(error "unknown #\\ name" name)))))
(else
(read-char port)))))
((char=? c #\()
(read-char port)
(list->vector (sub-read-list c port)))
;; ## should evaluate to the last REP-loop result.
((memq c '(#\b #\o #\d #\x #\i #\e))
(let ((string (sub-read-token #\# port)))
(or (string->number string)
(error "unsupported number syntax" string))))
; ((char=? c #\#) ; don't worry about this
; (read-char port)
; (make-last-value-expression))
(else
(error "unknown # syntax" c))))))
; Tokens
(define (sub-read-token c port)
(let loop ((l (list (preferred-case c))) (n 1))
(let ((c (peek-char port)))
(cond ((or (eof-object? c)
(vector-ref read-terminating?-vector (char->ascii c)))
(reverse-list->string l n))
(else
(loop (cons (preferred-case (read-char port)) l)
(+ n 1)))))))
(define (parse-token string)
(if (let ((c (string-ref string 0)))
(or (char-numeric? c) (char=? c #\+) (char=? c #\-) (char=? c #\.)))
(cond ((string->number string))
((member string strange-symbol-names)
(string->symbol string))
((string=? string ".")
dot)
(else
(error "unsupported number syntax" string)))
(string->symbol string)))
(define strange-symbol-names
'("+" "-" "..." "1+" "-1+")) ;The latter two only for S&ICP support