| sequential_music { $$ = $1; }
;
-/* An argument list. If a function \foo expects scm scm pitch, then the lexer expands \foo into the token sequence:
- MUSIC_FUNCTION EXPECT_PITCH EXPECT_SCM EXPECT_SCM EXPECT_NO_MORE_ARGS
-and this rule returns the reversed list of arguments. */
-
-/* Function argument lists come in a number of flavors. Whenever
- * LilyPond has to pick between different flavors, the decision is
- * either made because of tokens it has already seen, or it is
- * postponed until tokens suitable for making the decision come up.
- * For postponing decisions, it may be necessary that the competing
- * rules are written in a way making them compatible until a decision
- * can be made. Sometimes this is done by putting common traits into
- * a separate "common" rule set.
+/* Function argument lists are arguably the most complex part in the
+ * parser. They are pretty tricky to understand because of the way
+ * they are processed, and because of optional arguments that can be
+ * omitted. When there are several optional arguments in a row,
+ * omitting one automatically omits all following arguments. Optional
+ * arguments can only be omitted when either
*
- * function_arglist: a full argument list. Optional arguments at the
- * end of the list can only be skipped by writing \default in their
- * place.
+ * a) the omission is explicitly started with \default
+ * b) the omission is implicitly started by an argument not matching
+ * its predicate, and there is a mandatory argument later that can
+ * "catch" the argument that does not fit.
*
- * function_arglist_backup: an argument list ending in an optional
- * argument that may be skipped depending on its predicate.
+ * When argument parsing starts, the lexer pushes EXPECT_SCM tokens
+ * (corresponding to mandatory arguments and having a predicate
+ * function as semantic value) or EXPECT_OPTIONAL EXPECT_SCM (where
+ * the semantic value of the EXPECT_OPTIONAL token is the default to
+ * use when the optional argument is omitted, and EXPECT_SCM again has
+ * the argument predicate as semantic value) in reverse order to the
+ * parser, followed by EXPECT_NO_MORE_ARGS. The argument list is then
+ * processed inside-out while actual tokens are consumed.
*
- * function_arglist_skip: an argument list _not_ ending in an optional
- * argument that is actually taken.
+ * This means that the argument list tokens determine the actions
+ * taken as they arrive. The structure of the argument list is known
+ * to the parser and stored in its parse stack when the first argument
+ * is being parsed. What the parser does not know is which predicates
+ * will match and whether or not \default will be appearing in the
+ * argument list, and where.
*
- * function_arglist_nonbackup: an argument list ending in an optional
- * argument that may not be skipped because it is in end position and
- * has not been shortcircuited with \default.
+ * Many of the basic nonterminals used for argument list scanning come
+ * in a "normal" and a "closed" flavor. A closed expression is one
+ * that can be parsed without a lookahead token. That makes it
+ * feasible for an optional argument that may need to be skipped:
+ * skipping can only be accomplished by pushing back the token into
+ * the lexer, and that only works when there is no lookahead token.
+ *
+ * Sequences of 0 or more optional arguments are scanned using either
+ * function_arglist_backup or function_arglist_nonbackup. The first
+ * is used when optional arguments are followed by at least one
+ * mandatory argument: in that case optional arguments may be skipped
+ * by either a false predicate (in which case the expression will be
+ * pushed back as one or more tokens, preceded by a BACKUP token) or
+ * by using \default.
+ *
+ * If optional arguments are at the end of the argument list, they are
+ * instead scanned using function_arglist_nonbackup: here the only
+ * manner to enter into skipping of optional arguments is the use of
+ * \default.
+ *
+ * The argument list of a normal function call is parsed using
+ * function_arglist. The part of an argument list before a mandatory
+ * argument is parsed using function_arglist_optional.
+ *
+ * The difference is that leading optional arguments are scanned using
+ * function_arglist_nonbackup and function_arglist_backup,
+ * respectively.
+ *
+ * Most other details are obvious in the rules themselves.
*
- * function_arglist* / function_arglist_closed*: The closed variants
- * don't end in simple music expressions that might still accept
- * things like a duration or a postevent.
*/
-function_arglist_skip:
- function_arglist_common
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_skip
- {
- $$ = scm_cons ($1, $3);
- } %prec FUNCTION_ARGLIST
- ;
-
-
function_arglist_nonbackup_common:
- EXPECT_OPTIONAL EXPECT_SCM function_arglist FRACTION
+ EXPECT_OPTIONAL EXPECT_SCM function_arglist_nonbackup FRACTION
{
$$ = check_scheme_arg (parser, @4, $4, $3, $2);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed post_event_nofinger
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_nonbackup post_event_nofinger
{
$$ = check_scheme_arg (parser, @4, $4, $3, $2);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed '-' UNSIGNED
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_nonbackup '-' UNSIGNED
{
SCM n = scm_difference ($5, SCM_UNDEFINED);
if (scm_is_true (scm_call_1 ($2, n)))
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed '-' REAL
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_nonbackup '-' REAL
{
$$ = check_scheme_arg (parser, @4,
scm_difference ($5, SCM_UNDEFINED),
$3, $2);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed '-' NUMBER_IDENTIFIER
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_nonbackup '-' NUMBER_IDENTIFIER
{
$$ = check_scheme_arg (parser, @4,
scm_difference ($5, SCM_UNDEFINED),
function_arglist_closed_nonbackup:
function_arglist_nonbackup_common
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist embedded_scm_arg_closed
+ | function_arglist_closed_common
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_nonbackup embedded_scm_arg_closed
{
$$ = check_scheme_arg (parser, @4, $4, $3, $2);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed bare_number_closed
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_nonbackup bare_number_closed
{
$$ = check_scheme_arg (parser, @4, $4, $3, $2);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist SCM_IDENTIFIER
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_nonbackup SCM_IDENTIFIER
{
$$ = check_scheme_arg (parser, @4,
try_string_variants ($2, $4),
$3, $2, $4);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist STRING
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_nonbackup STRING
{
$$ = check_scheme_arg (parser, @4,
try_string_variants ($2, $4),
$3, $2, $4);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist full_markup
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_nonbackup full_markup
{
$$ = check_scheme_arg (parser, @4, $4, $3, $2);
}
function_arglist_nonbackup:
function_arglist_nonbackup_common
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist embedded_scm_arg
+ | function_arglist_common
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_nonbackup embedded_scm_arg
{
if (scm_is_true (scm_call_1 ($2, $4)))
$$ = scm_cons ($4, $3);
(parser, @4, $4),
$3, $2);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed bare_number_common
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_nonbackup bare_number_common
{
$$ = check_scheme_arg (parser, @4, $4, $3, $2);
}
;
function_arglist_nonbackup_reparse:
- EXPECT_OPTIONAL EXPECT_SCM function_arglist SCM_IDENTIFIER
+ EXPECT_OPTIONAL EXPECT_SCM function_arglist_nonbackup SCM_IDENTIFIER
{
$$ = $3;
SCM res = try_string_variants ($2, $4);
else
MYREPARSE (@4, $2, SCM_ARG, $4);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist STRING
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_nonbackup STRING
{
$$ = $3;
SCM res = try_string_variants ($2, $4);
else
MYREPARSE (@4, $2, SCM_ARG, $4);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist full_markup
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_nonbackup full_markup
{
$$ = $3;
if (scm_is_true (scm_call_1 ($2, $4)))
else
MYREPARSE (@4, $2, SCM_ARG, $4);
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed UNSIGNED
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_nonbackup UNSIGNED
{
$$ = $3;
if (scm_is_true (scm_call_1 ($2, $4)))
MYREPARSE (@4, $2, DURATION_IDENTIFIER, d);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed DURATION_IDENTIFIER {
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_nonbackup DURATION_IDENTIFIER {
$$ = $3;
MYREPARSE (@4, $2, DURATION_IDENTIFIER, $4);
}
;
-function_arglist_keep:
- function_arglist_common
- | function_arglist_backup
+
+function_arglist_backup:
+ function_arglist_backup_common
+ | function_arglist_common
;
-function_arglist_closed_keep:
- function_arglist_closed_common
- | function_arglist_backup
+function_arglist_closed_backup:
+ function_arglist_backup_common
+ | function_arglist_closed_common
;
-function_arglist_backup:
- EXPECT_OPTIONAL EXPECT_SCM function_arglist_keep embedded_scm_arg_closed
+function_arglist_backup_common:
+ EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup embedded_scm_arg_closed
{
if (scm_is_true (scm_call_1 ($2, $4)))
{
MYBACKUP (SCM_ARG, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep post_event_nofinger
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_backup post_event_nofinger
{
if (scm_is_true (scm_call_1 ($2, $4)))
{
MYBACKUP (EVENT_IDENTIFIER, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_keep full_markup
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup full_markup
{
if (scm_is_true (scm_call_1 ($2, $4)))
$$ = scm_cons ($4, $3);
MYBACKUP (LYRIC_ELEMENT, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep UNSIGNED
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_backup UNSIGNED
{
if (scm_is_true (scm_call_1 ($2, $4)))
{
}
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep REAL
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_backup REAL
{
if (scm_is_true (scm_call_1 ($2, $4)))
{
MYBACKUP (REAL, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep NUMBER_IDENTIFIER
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_backup NUMBER_IDENTIFIER
{
if (scm_is_true (scm_call_1 ($2, $4)))
{
MYBACKUP (NUMBER_IDENTIFIER, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_keep FRACTION
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup FRACTION
{
if (scm_is_true (scm_call_1 ($2, $4)))
{
MYBACKUP (FRACTION, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep '-' UNSIGNED
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_backup '-' UNSIGNED
{
SCM n = scm_difference ($5, SCM_UNDEFINED);
if (scm_is_true (scm_call_1 ($2, n))) {
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep '-' REAL
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_backup '-' REAL
{
SCM n = scm_difference ($5, SCM_UNDEFINED);
if (scm_is_true (scm_call_1 ($2, n))) {
MYBACKUP (REAL, n, @5);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep '-' NUMBER_IDENTIFIER
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_backup '-' NUMBER_IDENTIFIER
{
SCM n = scm_difference ($5, SCM_UNDEFINED);
if (scm_is_true (scm_call_1 ($2, n))) {
MYBACKUP (NUMBER_IDENTIFIER, n, @5);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_keep PITCH_IDENTIFIER
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup PITCH_IDENTIFIER
{
if (scm_is_true (scm_call_1 ($2, $4)))
{
MYBACKUP (PITCH_IDENTIFIER, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_keep NOTENAME_PITCH
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup NOTENAME_PITCH
{
if (scm_is_true (scm_call_1 ($2, $4)))
{
MYBACKUP (NOTENAME_PITCH, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_keep TONICNAME_PITCH
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup TONICNAME_PITCH
{
if (scm_is_true (scm_call_1 ($2, $4)))
{
MYBACKUP (TONICNAME_PITCH, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_keep DURATION_IDENTIFIER
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_closed_backup DURATION_IDENTIFIER
{
if (scm_is_true (scm_call_1 ($2, $4)))
{
MYBACKUP (DURATION_IDENTIFIER, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_keep SCM_IDENTIFIER
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup SCM_IDENTIFIER
{
SCM res = try_string_variants ($2, $4);
if (!SCM_UNBNDP (res))
MYBACKUP (SCM_IDENTIFIER, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_keep STRING
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup STRING
{
SCM res = try_string_variants ($2, $4);
if (!SCM_UNBNDP (res))
MYBACKUP (STRING, $4, @4);
}
}
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_backup BACKUP
- {
- $$ = scm_cons ($1, $3);
- MYBACKUP(0, SCM_UNDEFINED, @3);
- }
| function_arglist_backup REPARSE bare_number_common
{
$$ = check_scheme_arg (parser, @3,
;
function_arglist:
- function_arglist_common
- | function_arglist_nonbackup
+ function_arglist_nonbackup
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_skip_nonbackup DEFAULT
+ {
+ $$ = scm_cons (loc_on_music (@4, $1), $3);
+ }
+ ;
+
+function_arglist_skip_nonbackup:
+ function_arglist_nonbackup
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_skip_nonbackup
+ {
+ $$ = scm_cons (loc_on_music (@3, $1), $3);
+ }
;
function_arglist_common:
- function_arglist_bare
+ EXPECT_NO_MORE_ARGS {
+ $$ = SCM_EOL;
+ }
| EXPECT_SCM function_arglist_optional embedded_scm_arg
{
if (scm_is_true (scm_call_1 ($1, $3)))
;
function_arglist_closed:
- function_arglist_closed_common
- | function_arglist_closed_nonbackup
+ function_arglist_closed_nonbackup
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_skip_nonbackup DEFAULT
+ {
+ $$ = scm_cons (loc_on_music (@4, $1), $3);
+ }
;
function_arglist_closed_common:
- function_arglist_bare
+ EXPECT_NO_MORE_ARGS {
+ $$ = SCM_EOL;
+ }
| EXPECT_SCM function_arglist_optional embedded_scm_arg_closed
{
$$ = check_scheme_arg (parser, @3,
;
function_arglist_optional:
- function_arglist_keep %prec FUNCTION_ARGLIST
- | function_arglist_backup BACKUP
+ function_arglist_backup
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_skip_backup DEFAULT
+ {
+ $$ = scm_cons (loc_on_music (@4, $1), $3);
+ }
+ | function_arglist_skip_backup BACKUP
+ ;
+
+function_arglist_skip_backup:
+ function_arglist_backup
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_skip_backup
+ {
+ $$ = scm_cons (loc_on_music (@3, $1), $3);
+ }
;
function_arglist_closed_optional:
- function_arglist_closed_keep %prec FUNCTION_ARGLIST
- | function_arglist_backup BACKUP
+ function_arglist_closed_backup
+ | EXPECT_OPTIONAL EXPECT_SCM function_arglist_skip_backup DEFAULT
+ {
+ $$ = scm_cons (loc_on_music (@4, $1), $3);
+ }
+ | function_arglist_skip_backup BACKUP
;
embedded_scm_closed:
SCM_FUNCTION function_arglist_closed {
$$ = MAKE_SYNTAX ("music-function", @$,
$1, $2);
- } %prec FUNCTION_ARGLIST
- ;
-
-function_arglist_bare:
- EXPECT_NO_MORE_ARGS {
- $$ = SCM_EOL;
- }
- | EXPECT_OPTIONAL EXPECT_SCM function_arglist_skip DEFAULT {
- $$ = scm_cons ($1, $3);
}
;
projects / lilypond.git / commitdiff