+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep UNSIGNED
+ {
+ if (scm_is_true (scm_call_1 ($2, $4)))
+ {
+ $$ = scm_cons ($4, $3);
+ } else {
+ $$ = scm_cons (loc_on_music (@3, $1), $3);
+ MYBACKUP (UNSIGNED, $4, @4);
+ }
+ }
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep REAL
+ {
+ if (scm_is_true (scm_call_1 ($2, $4)))
+ {
+ $$ = scm_cons ($4, $3);
+ } else {
+ $$ = scm_cons (loc_on_music (@3, $1), $3);
+ MYBACKUP (REAL, $4, @4);
+ }
+ }
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep NUMBER_IDENTIFIER
+ {
+ if (scm_is_true (scm_call_1 ($2, $4)))
+ {
+ $$ = scm_cons ($4, $3);
+ } else {
+ $$ = scm_cons (loc_on_music (@3, $1), $3);
+ MYBACKUP (NUMBER_IDENTIFIER, $4, @4);
+ }
+ }
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep FRACTION
+ {
+ if (scm_is_true (scm_call_1 ($2, $4)))
+ {
+ $$ = scm_cons ($4, $3);
+ } else {
+ $$ = scm_cons (loc_on_music (@3, $1), $3);
+ MYBACKUP (FRACTION, $4, @4);
+ }
+ }
+ | EXPECT_OPTIONAL EXPECT_PITCH function_arglist_keep pitch_also_in_chords
+ {
+ $$ = scm_cons ($4, $3);
+ }
+ | EXPECT_OPTIONAL EXPECT_DURATION function_arglist_closed_keep duration_length
+ {
+ $$ = scm_cons ($4, $3);
+ }
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup BACKUP
+ {
+ $$ = scm_cons ($1, $3);
+ MYBACKUP(0, SCM_UNDEFINED, @3);
+ }