+music_property_def:
+ OVERRIDE context_prop_spec embedded_scm '=' scalar {
+ $$ = property_op_to_music (scm_list_4 (
+ ly_symbol2scm ("poppush"),
+ ly_cadr ($2),
+ $3, $5));
+ $$= context_spec_music (ly_car ($2), SCM_UNDEFINED, $$, SCM_EOL);
+ }
+ | REVERT context_prop_spec embedded_scm {
+ $$ = property_op_to_music (scm_list_3 (
+ ly_symbol2scm ("pop"),
+ ly_cadr ($2),
+ $3));
+
+ $$= context_spec_music (ly_car ($2), SCM_UNDEFINED, $$, SCM_EOL);
+ }
+ | SET context_prop_spec '=' scalar {
+ $$ = property_op_to_music (scm_list_3 (
+ ly_symbol2scm ("assign"),
+ ly_cadr ($2),
+ $4));
+ $$= context_spec_music (ly_car ($2), SCM_UNDEFINED, $$, SCM_EOL);
+ }
+ | UNSET context_prop_spec {
+ $$ = property_op_to_music (scm_list_2 (
+ ly_symbol2scm ("unset"),
+ ly_cadr ($2)));
+ $$= context_spec_music (ly_car ($2), SCM_UNDEFINED, $$, SCM_EOL);