From 9468b77cb2ae93b992bfb9105016f3393d206b47 Mon Sep 17 00:00:00 2001
From: David Kastrup <dak@gnu.org>
Date: Thu, 10 Dec 2015 13:05:59 +0100
Subject: [PATCH] Issue 5167/5: Allow defining markup commands in LilyPond
 syntax

This works with assignments of the form

    \markup with-red = \markup \with-color #red \etc

or similar.  The resulting definition (in addition to being available
as \with-red command inside of markups) can be used with the `markup'
macro and also gets a `make-with-red-markup' convenience function.
---
 lily/include/lily-imports.hh |  2 ++
 lily/lily-imports.cc         |  2 ++
 lily/parser.yy               | 55 ++++++++++++++++++++++++++++++++----
 3 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/lily/include/lily-imports.hh b/lily/include/lily-imports.hh
index a22da30f66..cc61ea7d9a 100644
--- a/lily/include/lily-imports.hh
+++ b/lily/include/lily-imports.hh
@@ -61,6 +61,7 @@ namespace Lily {
   extern Variable chordmodifiers;
   extern Variable construct_chord_elements;
   extern Variable default_time_signature_settings;
+  extern Variable define_markup_command;
   extern Variable drum_pitch_names;
   extern Variable grob_compose_function;
   extern Variable grob_offset_function;
@@ -87,6 +88,7 @@ namespace Lily {
   extern Variable make_span_event;
   extern Variable markup_p;
   extern Variable markup_command_signature;
+  extern Variable markup_function_p;
   extern Variable markup_list_function_p;
   extern Variable markup_list_p;
   extern Variable midi_program;
diff --git a/lily/lily-imports.cc b/lily/lily-imports.cc
index 699b0850e7..5bb4863168 100644
--- a/lily/lily-imports.cc
+++ b/lily/lily-imports.cc
@@ -55,6 +55,7 @@ namespace Lily {
   Variable chordmodifiers ("chordmodifiers");
   Variable construct_chord_elements ("construct-chord-elements");
   Variable default_time_signature_settings ("default-time-signature-settings");
+  Variable define_markup_command ("define-markup-command");
   Variable drum_pitch_names ("drumPitchNames");
   Variable grob_compose_function ("grob::compose-function");
   Variable grob_offset_function ("grob::offset-function");
@@ -81,6 +82,7 @@ namespace Lily {
   Variable make_span_event ("make-span-event");
   Variable markup_p ("markup?");
   Variable markup_command_signature ("markup-command-signature");
+  Variable markup_function_p ("markup-function?");
   Variable markup_list_function_p ("markup-list-function?");
   Variable markup_list_p ("markup-list?");
   Variable midi_program ("midi-program");
diff --git a/lily/parser.yy b/lily/parser.yy
index d9812b1b9f..ddccd41658 100644
--- a/lily/parser.yy
+++ b/lily/parser.yy
@@ -696,6 +696,20 @@ assignment:
 		parser->lexer_->set_identifier (path, $5);
                 $$ = SCM_UNSPECIFIED;
 	}
+	| markup_mode_word '=' identifier_init
+	{
+		if (scm_is_false (Lily::markup_function_p ($3)))
+		{
+			parser->parser_error (@3, _ ("Not a markup function"));
+		} else {
+			scm_primitive_eval
+				(scm_list_3
+				 (Lily::define_markup_command,
+				  scm_string_to_symbol ($1),
+				  ly_quote_scm ($3)));
+		}
+		$$ = SCM_UNSPECIFIED;
+	}
 	;
 
 
@@ -3899,11 +3913,33 @@ markup_mode:
 	}
 	;
 
+// Sort-of ugly: We need this as markup of its own as well as in
+// markup function assignments, without triggering lookahead or the
+// '=' for assignments will be parsed in markup mode and not
+// recognized.  Worse: the next token following something like
+// \markup "string" would be parsed in markup mode as well.
+//
+// So we make a single production here that's used either in markup or
+// in assignment.
+
+markup_mode_word:
+	markup_mode markup_word
+	{
+		$$ = $2;
+		parser->lexer_->pop_state ();
+	}
+	;
+
+
 full_markup:
 	markup_mode markup_top {
 		$$ = $2;
 		parser->lexer_->pop_state ();
 	}
+	| markup_mode_word
+	{
+		$$ = make_simple_markup ($1);
+	}
 	;
 
 partial_markup:
@@ -3923,7 +3959,7 @@ markup_top:
 		$$ = scm_car (MAKE_SYNTAX (composed_markup_list,
 					   @2, $1, scm_list_1 ($2)));
 	}
-	| simple_markup	{
+	| simple_markup_noword {
 		$$ = $1;
 	}
 	;
@@ -4070,14 +4106,21 @@ markup_head_1_list:
 	}
 	;
 
+markup_word:
+	STRING
+	| SYMBOL
+	;
+
 simple_markup:
-	STRING {
-		$$ = make_simple_markup ($1);
-	}
-	| SYMBOL {
+	markup_word
+	{
 		$$ = make_simple_markup ($1);
 	}
-	| SCORE {
+	| simple_markup_noword
+	;
+
+simple_markup_noword:
+	SCORE {
 		parser->lexer_->push_note_state (Lily::pitchnames);
 	} '{' score_body '}' {
 		Score *sc = unsmob<Score> ($4);
-- 
2.39.2