Fix some bugs in the dynamic engraver and PostScript backend

[lilypond.git] / scm / document-backend.scm

diff --git a/scm/document-backend.scm b/scm/document-backend.scm
index 0195ad9252fc0c84633415529aaa33c4d9199522..f71689d3c0a9965e8ee88a4cdef6a942736e7df6 100644 (file)
--- a/scm/document-backend.scm
+++ b/scm/document-backend.scm
@@ -2,7 +2,7 @@
 ;;;;
 ;;;; source file of the GNU LilyPond music typesetter
 ;;;; 
-;;;; (c) 2000--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
+;;;; (c) 2000--2006 Han-Wen Nienhuys <hanwen@cs.uu.nl>
 ;;;; Jan Nieuwenhuizen <janneke@gnu.org>
 
 (define (interface-doc-string interface grob-description)
@@ -139,10 +139,10 @@ node."
 ;;;;;;;;;;;;;;;;
 
 (define (lookup-interface name)
-  (let* ((entry (hashq-ref (ly:all-grob-interfaces) name '())))
-    (if (equal? entry #f)
-       (ly:error (_ "unknown interface: ~S") name))
-    entry))
+  (let* ((entry (hashq-ref (ly:all-grob-interfaces) name #f)))
+    (if entry
+       entry
+       (ly:error (_ "unknown Grob interface: ~S") name))))
 
 (define (all-interfaces-doc)
   (make <texi-node>