Issue 4487/1: Implement partial function calls

[lilypond.git] / lily / parser.yy

diff --git a/lily/parser.yy b/lily/parser.yy
index 25b7cd86c3e95f1ec6da4379b9fb6db3575fca6a..581791d256badd07139b44758f2ed9fedb4e4a1a 100644 (file)
--- a/lily/parser.yy
+++ b/lily/parser.yy
@@ -265,6 +265,7 @@ int yylex (YYSTYPE *s, YYLTYPE *loc, Lily_parser *parser);
 %token DESCRIPTION "\\description"
 %token DRUMMODE "\\drummode"
 %token DRUMS "\\drums"
+%token ETC "\\etc"
 %token FIGUREMODE "\\figuremode"
 %token FIGURES "\\figures"
 %token HEADER "\\header"
@@ -693,6 +694,25 @@ identifier_init_nonumber:
         | embedded_scm
        | full_markup_list
         | context_modification
+       | partial_function ETC
+       ;
+
+partial_function:
+       MUSIC_FUNCTION function_arglist_partial
+       {
+               $$ = MAKE_SYNTAX (partial_music_function, @$,
+                                 $1, $2);
+       }
+       | EVENT_FUNCTION function_arglist_partial
+       {
+               $$ = MAKE_SYNTAX (partial_music_function, @$,
+                                 $1, $2);
+       }
+       | SCM_FUNCTION function_arglist_partial
+       {
+               $$ = MAKE_SYNTAX (partial_music_function, @$,
+                                 $1, $2);
+       }
        ;
 
 context_def_spec_block:
@@ -2004,6 +2024,56 @@ function_arglist_skip_nonbackup:
        }
        ;
 
+// Partial function arglists are returned just in their incomplete
+// state: when combined with the music function, the missing parts of
+// the signature can be reconstructed
+//
+// To serve as a partial arglist, the argument list must absolutely
+// _not_ be in "skipping optional arguments" mode since then there is
+// some backup token that has nowhere to go before \etc.
+//
+// So we can skim off an arbitrary number of arguments from the end of
+// the argument list.  The argument list remaining afterwards has to
+// be in not-skipping-optional-arguments mode.
+
+function_arglist_partial:
+       EXPECT_SCM function_arglist_optional
+       {
+               $$ = $2;
+       }
+       | EXPECT_SCM function_arglist_partial_optional
+       {
+               $$ = $2;
+       }
+       | EXPECT_OPTIONAL EXPECT_SCM function_arglist_nonbackup
+       {
+               $$ = $3;
+       }
+       | EXPECT_OPTIONAL EXPECT_SCM function_arglist_partial
+       {
+               $$ = $3;
+       }
+       ;
+
+function_arglist_partial_optional:
+       EXPECT_SCM function_arglist_optional
+       {
+               $$ = $2;
+       }
+       | EXPECT_SCM function_arglist_partial_optional
+       {
+               $$ = $2;
+       }
+       | EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup
+       {
+               $$ = $3;
+       }
+       | EXPECT_OPTIONAL EXPECT_SCM function_arglist_partial_optional
+       {
+               $$ = $3;
+       }
+       ;
+
 function_arglist_common:
        EXPECT_NO_MORE_ARGS {
                $$ = SCM_EOL;