document use of ly_{car,cdr}

diff --git a/lily/include/lily-guile.hh b/lily/include/lily-guile.hh
index c2cfb8ebfca2f9961bee9bdc0a4f8d1aaeb415a0..6aa25f828a90ec8a3d980b3a7e89fa7b975c01c6 100644 (file)
--- a/lily/include/lily-guile.hh
+++ b/lily/include/lily-guile.hh
@@ -171,6 +171,10 @@ typedef SCM (*Scheme_function_2) (GUILE_ELLIPSIS);
 typedef SCM (*Scheme_function_3) (GUILE_ELLIPSIS);
 #endif
 
+
+/*
+  Inline these for performance reasons.
+ */
 #define scm_cdr ly_cdr
 #define scm_car ly_car