From 46a3f814c8d750e4ee28a63afa5274b93e2bb058 Mon Sep 17 00:00:00 2001
From: David Kastrup <dak@gnu.org>
Date: Tue, 13 Mar 2012 12:30:32 +0100
Subject: [PATCH] Implement 'apply context mod

---
 lily/context-def.cc        | 3 ++-
 lily/context-property.cc   | 2 ++
 ly/music-functions-init.ly | 4 ++++
 scm/lily-library.scm       | 4 ++++
 4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/lily/context-def.cc b/lily/context-def.cc
index fb8208acdd..9c988f4da9 100644
--- a/lily/context-def.cc
+++ b/lily/context-def.cc
@@ -146,7 +146,8 @@ Context_def::add_context_mod (SCM mod)
   else if (ly_symbol2scm ("pop") == tag
            || ly_symbol2scm ("push") == tag
            || ly_symbol2scm ("assign") == tag
-           || ly_symbol2scm ("unset") == tag)
+           || ly_symbol2scm ("unset") == tag
+	   || ly_symbol2scm ("apply") == tag)
     property_ops_ = scm_cons (mod, property_ops_);
   else if (ly_symbol2scm ("alias") == tag)
     context_aliases_ = scm_cons (sym, context_aliases_);
diff --git a/lily/context-property.cc b/lily/context-property.cc
index a9d7e2fc44..0c5e1ec55d 100644
--- a/lily/context-property.cc
+++ b/lily/context-property.cc
@@ -247,6 +247,8 @@ apply_property_operations (Context *tg, SCM pre_init_ops)
         }
       else if (type == ly_symbol2scm ("assign"))
         tg->set_property (scm_car (entry), scm_cadr (entry));
+      else if (type == ly_symbol2scm ("apply"))
+	scm_apply_1 (scm_car (entry), tg->self_scm (), scm_cdr (entry));
     }
 }
 
diff --git a/ly/music-functions-init.ly b/ly/music-functions-init.ly
index f9e30d33e2..783f7990ce 100644
--- a/ly/music-functions-init.ly
+++ b/ly/music-functions-init.ly
@@ -997,6 +997,10 @@ a context modification duplicating their effect.")
 		      (ly:music-property m 'symbol)
 		      (ly:music-property m 'grob-property-path)))))
 	   (case (ly:music-property m 'name)
+	     ((ApplyContext)
+	      (ly:add-context-mod mods
+				  (list 'apply
+					(ly:music-property m 'procedure))))
 	     ((SequentialMusic SimultaneousMusic)
 	      (for-each musicop (ly:music-property m 'elements)))
 	     ((ContextSpeccedMusic)
diff --git a/scm/lily-library.scm b/scm/lily-library.scm
index 2951639266..8d4e0a069f 100644
--- a/scm/lily-library.scm
+++ b/scm/lily-library.scm
@@ -298,6 +298,10 @@ bookoutput function"
 	  (case (ly:music-property m 'name)
 	    ((SequentialMusic SimultaneousMusic)
 	     (fold loop mods (ly:music-property m 'elements)))
+	    ((ApplyContext)
+	     (ly:add-context-mod mods
+				 (list 'apply
+				       (ly:music-property m 'procedure))))
 	    ((ContextSpeccedMusic)
 	     (let ((sym (ly:music-property m 'context-type)))
 	       (if (eq? sym 'Bottom)
-- 
2.39.5