1 ;;;; This file is part of LilyPond, the GNU music typesetter.
3 ;;;; Copyright (C) 2004--2011 Nicolas Sceaux <nicolas.sceaux@free.fr>
4 ;;;; Jan Nieuwenhuizen <janneke@gnu.org>
6 ;;;; LilyPond is free software: you can redistribute it and/or modify
7 ;;;; it under the terms of the GNU General Public License as published by
8 ;;;; the Free Software Foundation, either version 3 of the License, or
9 ;;;; (at your option) any later version.
11 ;;;; LilyPond is distributed in the hope that it will be useful,
12 ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
13 ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 ;;;; GNU General Public License for more details.
16 ;;;; You should have received a copy of the GNU General Public License
17 ;;;; along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
19 (define-public (read-lily-expression chr port)
20 "Read a lilypond music expression enclosed within @code{#@{} and @code{#@}}
21 from @var{port} and return the corresponding Scheme music expression.
22 @samp{$} and @samp{#} introduce immediate and normal Scheme forms."
24 (filename (port-filename port))
25 (line (port-line port))
26 (lily-string (call-with-output-string
32 (let ((x (read-char port)))
36 (do ((c (read-char port) (read-char port)))
38 (char=? (peek-char port) #\}))
39 ;; we stop when #} is encountered
42 ;; a #scheme or $scheme expression
43 (if (or (char=? c #\#) (char=? c #\$))
44 (let* ((p (ftell out))
45 (expr (read copycat)))
46 ;; kill unused lookahead, it has been
47 ;; written out already
49 ;; only put symbols and non-quote
50 ;; lists into closures -- constants
51 ;; don't need lexical environments
53 (if (or (symbol? expr)
55 (not (eq? 'quote (car expr)))))
57 (cons `(cons ,p (lambda () ,expr))
60 (ly:parser-clone parser (list ,@closures)))
61 (result (ly:parse-string-expression clone ,lily-string
64 (if (ly:parser-has-error? clone)
65 (ly:parser-error parser (_ "error in #{ ... #}")))
68 (read-hash-extend #\{ read-lily-expression)