summaryrefslogtreecommitdiff
path: root/syntax-highlight/scheme.scm
blob: 5b906c7d9519fabcbbf61b082a933a66c21f95e2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
;;; guile-syntax-highlight --- General-purpose syntax highlighter
;;; Copyright © 2015 David Thompson <davet@gnu.org>
;;;
;;; Guile-syntax-highlight is free software; you can redistribute it
;;; and/or modify it under the terms of the GNU Lesser General Public
;;; License as published by the Free Software Foundation; either
;;; version 3 of the License, or (at your option) any later version.
;;;
;;; Guile-syntax-highlight is distributed in the hope that it will be
;;; useful, but WITHOUT ANY WARRANTY; without even the implied
;;; warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
;;; See the GNU Lesser General Public License for more details.
;;;
;;; You should have received a copy of the GNU Lesser General Public
;;; License along with guile-syntax-highlight.  If not, see
;;; <http://www.gnu.org/licenses/>.

;;; Commentary:
;;
;; Syntax highlighting for Scheme.
;;
;;; Code:

(define-module (syntax-highlight scheme)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-11)
  #:use-module (srfi srfi-41)
  #:use-module (syntax-highlight parsers)
  #:export (%default-special-symbols
            %default-special-regexps
            make-scheme-highlighter
            scheme-highlighter))

(define char-set:lisp-delimiters
  (char-set-union char-set:whitespace
                  (char-set #\( #\) #\[ #\] #\{ #\})))

(define (lisp-delimiter? char)
  (char-set-contains? char-set:lisp-delimiters char))

(define parse-symbol-chars
  (parse-char-set
   (char-set-complement char-set:lisp-delimiters)))

(define (parse-specials special-words)
  "Create a parser for SPECIAL-WORDS, a list of important terms for a
language."
  (define (special word)
    (let ((parser (tagged-parser 'special (parse-string word))))
      (lambda (stream)
        (let-values (((result rest-of-stream) (parser stream)))
          (if (and result (lisp-delimiter? (stream-car stream)))
              (values result rest-of-stream)
              (parse-fail stream))))))

  (fold parse-either parse-fail (map special special-words)))

(define (parse-specials/regexp special-regexps)
  (let ((merged-regexp
         (string-join (map (lambda (regexp)
                             (string-append "(" regexp ")"))
                           special-regexps)
                      "|")))
    (tagged-parser 'special
                   (parse-regexp merged-regexp parse-symbol-chars))))

(define (parse-openers openers)
  (define (open opener)
    (tagged-parser 'open (parse-string opener)))

  (fold parse-either parse-fail (map open openers)))

(define (parse-closers closers)
  (define (close closer)
    (tagged-parser 'close (parse-string closer)))

  (fold parse-either parse-fail (map close closers)))

(define parse-symbol
  (tagged-parser 'symbol
                 (parse-char-set
                  (char-set-complement char-set:lisp-delimiters))))

(define parse-keyword
  (tagged-parser 'keyword
                 (parse-map string-concatenate
                            (parse-each (parse-string "#:")
                                        parse-symbol-chars))))

(define parse-string-literal
  (tagged-parser 'string (parse-delimited "\"")))

(define parse-comment
  (tagged-parser 'comment (parse-delimited ";" #:until "\n")))

(define parse-quoted-symbol
  (tagged-parser 'symbol (parse-delimited "#{" #:until "}#")))

(define %default-special-symbols
  '("define" "begin" "call-with-current-continuation" "call/cc"
    "call-with-input-file" "call-with-output-file"
    "case" "cond"
    "do" "else" "if"
    "lambda" "λ"
    "let" "let*" "let-syntax" "letrec" "letrec-syntax"
    "export" "import" "library" "define-module" "use-module"
    "let-values" "let*-values"
    "and" "or"
    "delay" "force"
    "map" "for-each"
    "syntax" "syntax-rules"))

(define %default-special-regexps
  '("^define"))

(define* (make-scheme-highlighter special-symbols special-regexps)
  "Create a syntax highlighting procedure for Scheme that associates
the 'special' tag for symbols appearing in the list SPECIAL-SYMBOLS or
matching a regular expression in SPECIAL-REGEXPS."
  (parse-many
   (parse-any parse-whitespace
              (parse-openers '("(" "[" "{"))
              (parse-closers '(")" "]" "}"))
              (parse-specials special-symbols)
              (parse-specials/regexp special-regexps)
              parse-string-literal
              parse-comment
              parse-keyword
              parse-quoted-symbol
              parse-symbol)))

(define scheme-highlighter
  (make-scheme-highlighter %default-special-symbols
                           %default-special-regexps))