Issue 3352: Don't let eval-carefully bomb out on scalar non-symbols

This caused a programming error on invalid paper sizes.

diff --git a/scm/lily-library.scm b/scm/lily-library.scm
index d87bca208ac8e370679f35d622c5bef5d8d906ca..939e5caa8807554f3a1e1f87e66de8d8045a9fe8 100644 (file)
--- a/scm/lily-library.scm
+++ b/scm/lily-library.scm
@@ -932,13 +932,10 @@ in module @var{module}.  In that case evaluate, otherwise
 print a warning and set an optional @var{default}."
   (let* ((unavailable? (lambda (sym)
                          (not (module-defined? module sym))))
-        (sym-unavailable (if (pair? symbol)
-                             (filter
-                               unavailable?
-                               (filter symbol? (flatten-list symbol)))
-                             (if (unavailable? symbol)
-                                  #t
-                                  '()))))
+        (sym-unavailable
+          (filter
+           unavailable?
+           (filter symbol? (flatten-list symbol)))))
     (if (null? sym-unavailable)
         (eval symbol module)
         (let* ((def (and (pair? default) (car default))))