don't barf if a comparison has no source

[lilypond.git] / ly / init.ly

diff --git a/ly/init.ly b/ly/init.ly
index 091ae681949b403568838ad94af089a4bca5ca61..c3db3b37170810826995247621026c213d36379f 100644 (file)
--- a/ly/init.ly
+++ b/ly/init.ly
@@ -15,6 +15,7 @@
 #(define $defaultheader #f)
 #(define version-seen #f)
 #(define expect-error #f) 
+#(define output-empty-score-list #f)
 
 #(use-modules (scm clip-region))
 \maininput
@@ -33,7 +34,7 @@
       (defined? 'input-file-name))
   (version-not-seen-message input-file-name))
 
-#(if (pair? toplevel-scores)
+#(if (or (pair? toplevel-scores) output-empty-score-list)
   ((if (defined? 'default-toplevel-book-handler)
     default-toplevel-book-handler
     toplevel-book-handler)
@@ -41,5 +42,7 @@
    (apply ly:make-book $defaultpaper $defaultheader toplevel-scores)))
 
 
-#(if expect-error
-  (ly:parser-clear-error parser))
+#(if (eq? expect-error (ly:parser-has-error? parser))
+  (ly:parser-clear-error parser)
+  (if expect-error
+   (ly:parser-error parser (_ "expected error, but none found"))))