cyclone/scheme/read.sld
Justin Ethier ab25e360a9 Merge #497
2022-12-09 13:29:56 -08:00

317 lines
11 KiB
Scheme

;;;; Cyclone Scheme
;;;; https://github.com/justinethier/cyclone
;;;;
;;;; Copyright (c) 2014-2016, Justin Ethier
;;;; All rights reserved.
;;;;
;;;; This module contains the s-expression parser and supporting functions.
;;;;
(define-library (scheme read)
(import (scheme base)
(scheme cyclone common)
(scheme cyclone util)
;(scheme write)
(scheme char))
(export
read
read-all
read-all/source
include
include-ci)
(inline
Cyc-opaque-eq?
Cyc-opaque-unsafe-eq?
Cyc-opaque-unsafe-string?
Cyc-opaque-unsafe-string->number)
(begin
(define *sym-dot* (string->symbol "."))
(define *sym-unquote-splicing* (string->symbol ",@"))
(define *sym-datum-comment* (string->symbol "#;"))
(define-syntax include
(er-macro-transformer
(lambda (expr rename compare)
(define (dirname filename)
(let loop ((index (string-length filename)))
(if (zero? index)
""
(let ((index (- index 1)))
(if (char=? (string-ref filename index) #\/)
(substring filename 0 index)
(loop index))))))
(define (massage filename)
(cond
;; may happen in the REPL
((not (current-expand-filepath)) filename)
;; absolute filename
((char=? (string-ref filename 0) #\/) filename)
;; otherwise, open the file relative to the library that is
;; expanded
(else (let ((target (string-append (dirname (current-expand-filepath)) "/" filename)))
;; if the target exists use, otherwise fallback to the
;; backward compatible behavior.
(if (file-exists? target)
target
filename)))))
`(begin
,@(let ((filename (massage (cadr expr))))
(call-with-port
(open-input-file filename)
(lambda (port)
(read-all/source port filename))))))))
(define-syntax include-ci
(er-macro-transformer
(lambda (expr rename compare)
`(include ,@(cdr expr)))))
;; Convert a list read by the reader into an improper list
(define (->dotted-list lst)
(cond
((null? lst) '())
((equal? (car lst) *sym-dot*)
(cadr lst))
(else
(cons (car lst) (->dotted-list (cdr lst))))))
;; Main lexer/parser
(define read
(lambda args
(let ((fp (if (null? args)
(current-input-port)
(car args)))
(ssi! (if (and (pair? args)
(pair? (cdr args)))
(cadr args)
#f)) ;; Default
(fname (if (and (pair? args)
(pair? (cdr args))
(pair? (cddr args)))
(caddr args)
#f)))
(let ((result (parse fp ssi! fname)))
(if (Cyc-opaque? result)
(read-error fp fname "unexpected closing parenthesis")
result)))))
;; Read given file, collecting source location information so we
;; can give meaningful compiler error messages
(define (read-all/source port filename)
(read-all port store-source-info! filename))
;; read-all -> port -> [objects]
(define (read-all . args)
(let* ((fp (if (null? args)
(current-input-port)
(car args)))
(ssi! (if (and (pair? args)
(pair? (cdr args)))
(cadr args)
#f)) ;; Default
(fname (if (and ssi!
(pair? (cddr args)))
(caddr args)
#f)))
(define (loop fp result)
(let ((obj (read fp ssi! fname)))
(if (eof-object? obj)
(reverse result)
(loop fp (cons obj result)))))
(loop fp '())))
;;(define-c reading-from-file?
;; "(void *data, int argc, closure _, object k, object port)"
;; " object result = boolean_f;
;; Cyc_check_port(data, port);
;; if (((port_type *)port)->flags == 1) {
;; result = boolean_t;
;; }
;; return_closcall1(data, k, result);")
(define-c read-token
"(void *data, int argc, closure _, object k, object port)"
" Cyc_io_read_token(data, k, port);")
(define-c read-error
"(void *data, object _, int argc, object *args)"
" object port = args[1];
object filename = args[2];
object msg = args[3];
char buf[1024];
port_type *p;
Cyc_check_port(data, port);
Cyc_check_str(data, msg);
p = ((port_type *)port);
if (Cyc_is_string(filename) == boolean_t) {
snprintf(buf, 1023, \"at line %d, column %d of %s: %s\",
p->line_num, p->col_num,
string_str(filename),
string_str(msg));
} else {
snprintf(buf, 1023, \"at line %d, column %d: %s\",
p->line_num, p->col_num, string_str(msg));
}
Cyc_rt_raise_msg(data, buf);")
(define-c Cyc-opaque-eq?
"(void *data, int argc, closure _, object k, object opq, object obj)"
" if (Cyc_is_opaque(opq) == boolean_f)
return_closcall1(data, k, boolean_f);
return_closcall1(data, k, equalp( opaque_ptr(opq), obj ));"
"(void *data, object ptr, object opq, object obj)"
" if (Cyc_is_opaque(opq) == boolean_f)
return(boolean_f);
return(equalp( opaque_ptr(opq), obj ));")
(define-c Cyc-opaque-unsafe-eq?
"(void *data, int argc, closure _, object k, object opq, object obj)"
" return_closcall1(data, k, equalp( opaque_ptr(opq), obj ));"
"(void *data, object ptr, object opq, object obj)"
" return(equalp( opaque_ptr(opq), obj ));")
(define-c Cyc-opaque-unsafe-string?
"(void *data, int argc, closure _, object k, object opq)"
" return_closcall1(data, k, Cyc_is_string(opaque_ptr(opq)));"
"(void *data, object ptr, object opq)"
" return(Cyc_is_string(opaque_ptr(opq)));")
(define-c Cyc-opaque-unsafe-string->number
"(void *data, int argc, closure _, object k, object opq)"
" Cyc_string2number_(data, k, opaque_ptr(opq));")
(define-c Cyc-make-rect
"(void *data, int argc, closure _, object k, object r, object i)"
" Cyc_make_rectangular(data, k, r, i); ")
(define-c get-line-num
"(void *data, int argc, closure _, object k, object port)"
" int num = ((port_type *)port)->line_num;
return_closcall1(data, k, obj_int2obj(num)); ")
(define-c get-col-num
"(void *data, int argc, closure _, object k, object port)"
" int num = ((port_type *)port)->col_num;
return_closcall1(data, k, obj_int2obj(num)); ")
(define (store-source-info! obj filename line col)
(set! *reader-source-db*
(cons (cons obj (vector filename line col))
*reader-source-db*)))
;; TODO: where to store? Need to use a hashtable but also needs to
;; be accessible from macro's. probably needs to be in global env,
;; see (cyclone foreign) for an example
;; TODO: need corresponding macro (syntax-error/source ??) to use this
;; information for error reporting
;; TODO: probably want to have a top-level exception handler on macro
;; expansion and call compiler error to report any error along with
;; source info
;; Parse given input port and retrieve next token
;;
;; Params:
;; fp - Input port
;; ssi! - "Store Source Info" function, or #f if none
;; fname - Filename being read, or #f if N/A
;;
;; Returns read token
(define (parse fp ssi! fname)
(let ((token (read-token fp)))
;;(display "//")(write `(token ,token)) (newline)
(cond
((Cyc-opaque? token)
(cond
((Cyc-opaque-unsafe-string? token)
(Cyc-opaque-unsafe-string->number token))
;; Open paren, start read loop
((Cyc-opaque-unsafe-eq? token #\()
(let ((line-num (get-line-num fp))
(col-num (get-col-num fp)))
(let loop ((lis '())
(t (parse fp ssi! fname)))
(cond
((eof-object? t)
(read-error fp fname "missing closing parenthesis"))
((Cyc-opaque-eq? t #\))
(if (and (> (length lis) 2)
(equal? (cadr lis) *sym-dot*))
(->dotted-list (reverse lis))
(let ((result (reverse lis)))
(when (and ssi!
(pair? result)
(symbol? (car result)))
;; Possible macro expansion, save source info
(ssi! result
fname
line-num
(- col-num 1))) ;; Account for open paren
result)))
(else
(loop (cons t lis) (parse fp ssi! fname)))))))
((Cyc-opaque-unsafe-eq? token #\')
(list 'quote (parse fp ssi! fname)))
((Cyc-opaque-unsafe-eq? token #\`)
(list 'quasiquote (parse fp ssi! fname)))
((Cyc-opaque-unsafe-eq? token #\,)
(list 'unquote (parse fp ssi! fname)))
(else
token))) ;; error if this is returned to original caller of parse
((vector? token)
(cond
((= (vector-length token) 3) ;; Special case: exact/inexact number
(if (vector-ref token 2)
(exact (string->number (vector-ref token 0) (vector-ref token 1)))
(inexact (string->number (vector-ref token 0) (vector-ref token 1)))))
((= (vector-length token) 2) ;; Special case: special symbols
(let ((t (vector-ref token 0)))
(cond
((eq? t *sym-unquote-splicing*)
(list 'unquote-splicing (parse fp ssi! fname)))
((eq? t *sym-datum-comment*)
(parse fp ssi! fname) ;; Ignore next datum
(parse fp ssi! fname))
((string? t) ;; Special case: complex number
(let* ((end (vector-ref token 1))
(len (string-length t))
(only-imag? (= (+ 1 end) len)) ;; EG: "57i" with no real component
(real-str (if only-imag?
"0"
(substring t 0 end)))
(imag-str (if only-imag?
(substring t 0 end)
(substring t end (- len 1))))
(real (string->number real-str))
(imag (string->number imag-str))
)
(Cyc-make-rect real imag)))
(else
(error "Unexpected token" t)))))
((= (vector-length token) 1) ;; Special case: error
(error (vector-ref token 0)))
(else
(let loop ((lis '())
(t (parse fp ssi! fname)))
(cond
((eof-object? t)
(read-error fp fname "missing closing parenthesis"))
((Cyc-opaque-eq? t #\))
(list->vector (reverse lis)))
(else
(loop (cons t lis) (parse fp ssi! fname))))))))
((bytevector? token)
(let loop ((lis '())
(t (parse fp ssi! fname)))
(cond
((eof-object? t)
(read-error fp fname "missing closing parenthesis"))
((Cyc-opaque-eq? t #\))
(apply bytevector (reverse lis)))
(else
(loop (cons t lis) (parse fp ssi! fname))))))
(else
token))))
))