X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fmusic-function-scheme.cc;h=e9e9a68ec6f696859e3c66e3e3fe2dd778cc50e2;hb=771503749e5fa4a4e579f0c81731b142b4c2b4f6;hp=8470a97005e4d57db4c57203ee108459b217bc26;hpb=14141519116528444054b33419d910903f902ee7;p=lilypond.git

diff --git a/lily/music-function-scheme.cc b/lily/music-function-scheme.cc
index 8470a97005..e9e9a68ec6 100644
--- a/lily/music-function-scheme.cc
+++ b/lily/music-function-scheme.cc
@@ -13,7 +13,16 @@ LY_DEFINE (ly_music_function_extract, "ly:music-function-extract", 1, 0, 0,
 {
   LY_ASSERT_TYPE (is_music_function, x, 1);
 
-  return SCM_CELL_OBJECT_1 (x);
+  return get_music_function_transform (x);
+}
+
+LY_DEFINE (ly_music_function_signature, "ly:music-function-signature", 1, 0, 0,
+           (SCM x),
+           "Return the function signature inside@tie{}@var{x}.")
+{
+  LY_ASSERT_TYPE (is_music_function, x, 1);
+
+  return get_music_function_signature (x);
 }
 
 LY_DEFINE (ly_make_music_function, "ly:make-music-function", 2, 0, 0,
@@ -24,7 +33,20 @@ LY_DEFINE (ly_make_music_function, "ly:make-music-function", 2, 0, 0,
            " containing either @code{ly:music?} predicates or other type"
            " predicates.  Its car is the syntax function to call.")
 {
-  LY_ASSERT_TYPE (ly_is_procedure, func, 1);
+  LY_ASSERT_TYPE (ly_is_list, signature, 1);
+  LY_ASSERT_TYPE (ly_is_procedure, func, 2);
+  int n = 0;
+  for (SCM p = signature; scm_is_pair (p); p = scm_cdr (p), ++n)
+    {
+      SCM proc = scm_car (p);
+      if (scm_is_pair (proc))
+        proc = scm_car (proc);
+      if (scm_is_false (scm_procedure_p (proc)))
+        {
+          scm_wrong_type_arg_msg ("music-function", n, p,
+                                  "music function predicate");
+        }
+    }
+
   return make_music_function (signature, func);
 }
-