286 lines
7.9 KiB
Scheme
286 lines
7.9 KiB
Scheme
|
; -*- 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
|