Issue 1320: Scheme bar line interface (part 1/2: recoding)

[lilypond.git] / lily / grob-scheme.cc

diff --git a/lily/grob-scheme.cc b/lily/grob-scheme.cc
index e56e02d27a40c2e709d4ba18ad72df086005a48c..81ff7864ff36b4b4ff972bb0fc3051d8700f60e5 100644 (file)
--- a/lily/grob-scheme.cc
+++ b/lily/grob-scheme.cc
@@ -453,3 +453,16 @@ LY_DEFINE (ly_grob_chain_callback, "ly:grob-chain-callback",
   chain_callback (gr, proc, sym);
   return SCM_UNSPECIFIED;
 }
+
+LY_DEFINE (ly_grob_vertical_less_p, "ly:grob-vertical<?",
+           2, 0, 0, (SCM a, SCM b),
+           "Does @var{a} lie above @var{b} on the page?")
+{
+  LY_ASSERT_SMOB (Grob, a, 1);
+  LY_ASSERT_SMOB (Grob, b, 2);
+
+  Grob *ga = unsmob_grob (a);
+  Grob *gb = unsmob_grob (b);
+
+  return ly_bool2scm (Grob::vertical_less (ga, gb));
+}