1 ;;;; ly-from-scheme.scm -- parsing LilyPond music expressions from scheme
3 ;;;; source file of the GNU LilyPond music typesetter
5 ;;;; (c) 2004--2008 Nicolas Sceaux <nicolas.sceaux@free.fr>
6 ;;;; Jan Nieuwenhuizen <janneke@gnu.org>
9 ;; Generate a lilyvartmpXX symbol, that may be (hopefully) unique.
12 (set! var-idx (1+ var-idx))
13 (string->symbol (format #f "lilyvartmp~a"
14 (list->string (map (lambda (chr)
15 (integer->char (+ (char->integer #\a)
16 (- (char->integer chr)
17 (char->integer #\0)))))
18 (string->list (number->string var-idx)))))))))
20 (define-public (parse-string-result str parser)
21 "Parse `str', which is supposed to contain a music expression."
23 (ly:parser-parse-string
25 (format #f "parseStringResult = \\notemode { ~a }" str))
26 (ly:parser-lookup parser 'parseStringResult))
28 (define-public (read-lily-expression chr port)
29 "Read a #{ lily music expression #} from port and return
30 the scheme music expression. The $ character may be used to introduce
31 scheme forms, typically symbols. $$ may be used to simply write a `$'
35 (define (create-binding! val)
36 "Create a new symbol, bind it to `val' and return it."
37 (let ((tmp-symbol (gen-lily-sym)))
38 (set! bindings (cons (cons tmp-symbol val) bindings))
41 (define (remove-dollars! form)
42 "Generate a form where `$variable' and `$ value' mottos are replaced
43 by new symbols, which are binded to the adequate values."
46 (string=? (substring (symbol->string form) 0 1) "$")
47 (not (and (<= 2 (string-length (symbol->string form)))
48 (string=? (substring (symbol->string form) 1 2) "$"))))
49 (create-binding! (string->symbol (substring (symbol->string form) 1))))
51 (not (pair? form)) form)
54 (cons (create-binding! (cadr form)) (remove-dollars! (cddr form))))
55 (else ;; (something ...)
56 (cons (remove-dollars! (car form)) (remove-dollars! (cdr form))))))
58 (let ((lily-string (call-with-output-string
60 (do ((c (read-char port) (read-char port)))
62 (char=? (peek-char port) #\})) ;; we stop when #} is encoutered
66 ((and (char=? c #\$) (not (char=? (peek-char port) #\$)))
67 (format out "\\~a" (create-binding! (read port))))
69 ((and (char=? c #\$) (char=? (peek-char port) #\$))
71 (display (read-char port) out))
72 ;; a #scheme expression
74 (let ((expr (read port)))
75 (format out "#~s" (if (eq? '$ expr)
76 (create-binding! (read port))
77 (remove-dollars! expr)))))
80 (display c out))))))))
81 `(let ((parser-clone (ly:parser-clone parser)))
82 ,@(map (lambda (binding)
83 `(ly:parser-define! parser-clone ',(car binding) ,(cdr binding)))
85 (parse-string-result ,lily-string parser-clone)))))
87 (read-hash-extend #\{ read-lily-expression)