You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
beautiful-racket/brag/brag/codegen/reader.rkt

69 lines
3.0 KiB
Racket

#lang s-exp syntax/module-reader
brag/codegen/sexp-based-lang
#:read my-read
#:read-syntax my-read-syntax
#:info my-get-info
#:whole-body-readers? #t
(require brag/rules/parser
brag/rules/lexer
brag/rules/stx
brag/rules/rule-structs)
(define (my-read in)
(syntax->datum (my-read-syntax #f in)))
(define (my-read-syntax src in)
(define-values (first-line first-column first-position) (port-next-location in))
(define tokenizer (tokenize in))
(define rules
(parameterize ([current-parser-error-handler
(lambda (tok-ok? tok-name tok-value start-pos end-pos)
(raise-syntax-error
#f
(format "Error while parsing grammar near: ~a [line=~a, column=~a, position=~a]"
tok-value
(pos-line start-pos)
(pos-col start-pos)
(pos-offset start-pos))
(datum->syntax #f
(string->symbol (format "~a" tok-value))
(list src
(pos-line start-pos)
(pos-col start-pos)
(pos-offset start-pos)
(if (and (number? (pos-offset end-pos))
(number? (pos-offset start-pos)))
(- (pos-offset end-pos)
(pos-offset start-pos))
#f)))))])
(grammar-parser tokenizer)))
(define-values (last-line last-column last-position) (port-next-location in))
(list (rules->stx src rules
#:original-stx (datum->syntax #f 'original-stx
(list src
first-line
first-column
first-position
(if (and (number? last-position)
(number? first-position))
(- last-position first-position)
#f))))))
;; Extension: we'd like to cooperate with DrRacket and tell
;; it to use the default, textual lexer and color scheme when
;; editing bf programs.
;;
;; See: http://docs.racket-lang.org/guide/language-get-info.html
;; for more details, as well as the documentation in
;; syntax/module-reader.
(define (my-get-info key default default-filter)
(case key
[(color-lexer)
(dynamic-require 'syntax-color/default-lexer
'default-lexer)]
[else
(default-filter key default)]))