-;;;; ly-from-scheme.scm -- parsing LilyPond music expressions from scheme
+;;;; This file is part of LilyPond, the GNU music typesetter.
;;;;
-;;;; source file of the GNU LilyPond music typesetter
-;;;;
-;;;; (c) 2004--2008 Nicolas Sceaux <nicolas.sceaux@free.fr>
+;;;; Copyright (C) 2004--2015 Nicolas Sceaux <nicolas.sceaux@free.fr>
;;;; Jan Nieuwenhuizen <janneke@gnu.org>
-
-(define gen-lily-sym
- ;; Generate a lilyvartmpXX symbol, that may be (hopefully) unique.
- (let ((var-idx -1))
- (lambda ()
- (set! var-idx (1+ var-idx))
- (string->symbol (format #f "lilyvartmp~a"
- (list->string (map (lambda (chr)
- (integer->char (+ (char->integer #\a)
- (- (char->integer chr)
- (char->integer #\0)))))
- (string->list (number->string var-idx)))))))))
-
-(define-public (parse-string-result str parser)
- "Parse `str', which is supposed to contain a music expression."
-
- (ly:parser-parse-string
- parser
- (format #f "parseStringResult = \\notemode { ~a }" str))
- (ly:parser-lookup parser 'parseStringResult))
+;;;;
+;;;; LilyPond is free software: you can redistribute it and/or modify
+;;;; it under the terms of the GNU General Public License as published by
+;;;; the Free Software Foundation, either version 3 of the License, or
+;;;; (at your option) any later version.
+;;;;
+;;;; LilyPond 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 General Public License for more details.
+;;;;
+;;;; You should have received a copy of the GNU General Public License
+;;;; along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
(define-public (read-lily-expression chr port)
- "Read a #{ lily music expression #} from port and return
-the scheme music expression. The $ character may be used to introduce
-scheme forms, typically symbols. $$ may be used to simply write a `$'
-character."
- (let ((bindings '()))
-
- (define (create-binding! val)
- "Create a new symbol, bind it to `val' and return it."
- (let ((tmp-symbol (gen-lily-sym)))
- (set! bindings (cons (cons tmp-symbol val) bindings))
- tmp-symbol))
-
- (define (remove-dollars! form)
- "Generate a form where `$variable' and `$ value' mottos are replaced
- by new symbols, which are binded to the adequate values."
- (cond (;; $variable
- (and (symbol? form)
- (string=? (substring (symbol->string form) 0 1) "$")
- (not (and (<= 2 (string-length (symbol->string form)))
- (string=? (substring (symbol->string form) 1 2) "$"))))
- (create-binding! (string->symbol (substring (symbol->string form) 1))))
- (;; atom
- (not (pair? form)) form)
- (;; ($ value ...)
- (eqv? (car form) '$)
- (cons (create-binding! (cadr form)) (remove-dollars! (cddr form))))
- (else ;; (something ...)
- (cons (remove-dollars! (car form)) (remove-dollars! (cdr form))))))
-
- (let ((lily-string (call-with-output-string
- (lambda (out)
- (do ((c (read-char port) (read-char port)))
- ((and (char=? c #\#)
- (char=? (peek-char port) #\})) ;; we stop when #} is encoutered
- (read-char port))
- (cond
- ;; a $form expression
- ((and (char=? c #\$) (not (char=? (peek-char port) #\$)))
- (format out "\\~a" (create-binding! (read port))))
- ;; just a $ character
- ((and (char=? c #\$) (char=? (peek-char port) #\$))
- ;; pop the second $
- (display (read-char port) out))
- ;; a #scheme expression
- ((char=? c #\#)
- (let ((expr (read port)))
- (format out "#~s" (if (eq? '$ expr)
- (create-binding! (read port))
- (remove-dollars! expr)))))
- ;; other caracters
- (else
- (display c out))))))))
- `(let ((parser-clone (ly:parser-clone parser)))
- ,@(map (lambda (binding)
- `(ly:parser-define! parser-clone ',(car binding) ,(cdr binding)))
- (reverse bindings))
- (parse-string-result ,lily-string parser-clone)))))
+ "Read a lilypond music expression enclosed within @code{#@{} and @code{#@}}
+from @var{port} and return the corresponding Scheme music expression.
+@samp{$} and @samp{#} introduce immediate and normal Scheme forms."
+ (let* ((closures '())
+ (filename (port-filename port))
+ (line (port-line port))
+ (lily-string (call-with-output-string
+ (lambda (out)
+ (let ((copycat
+ (make-soft-port
+ (vector #f #f #f
+ (lambda ()
+ (let ((x (read-char port)))
+ (write-char x out)
+ x)) #f)
+ "r")))
+ (set-port-filename! copycat filename)
+ (do ((c (read-char port) (read-char port)))
+ ((and (char=? c #\#)
+ (char=? (peek-char port) #\}))
+ ;; we stop when #} is encountered
+ (read-char port))
+ (write-char c out)
+ ;; a #scheme or $scheme expression
+ (if (or (char=? c #\#) (char=? c #\$))
+ (let* ((p (ftell out))
+ (expr
+ (begin
+ (set-port-line! copycat
+ (port-line port))
+ (set-port-column! copycat
+ (port-column port))
+ (if (char=? (peek-char port) #\@)
+ (read-char copycat))
+ (read copycat))))
+ ;; kill unused lookahead, it has been
+ ;; written out already
+ (drain-input copycat)
+ ;; only put symbols and non-quote
+ ;; lists into closures -- constants
+ ;; don't need lexical environments
+ ;; for evaluation.
+ (if (or (symbol? expr)
+ (and (pair? expr)
+ (not (eq? 'quote (car expr)))))
+ (set! closures
+ (cons `(cons ,p (lambda () ,expr))
+ closures)))))))))))
+ (define (embedded-lilypond lily-string filename line closures)
+ (let* ((clone (ly:parser-clone closures (*location*)))
+ (result (ly:parse-string-expression clone lily-string
+ filename line)))
+ (if (ly:parser-has-error? clone)
+ (ly:parser-error (_ "error in #{ ... #}") (*location*)))
+ result))
+ (list embedded-lilypond
+ lily-string filename line
+ (cons 'list (reverse! closures)))))
(read-hash-extend #\{ read-lily-expression)
projects / lilypond.git / blobdiff