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[Accessor] When successful, returns the rank of the rule with ID rule_id. When a rule is created, its rank is initialized to the default rank of the grammar. The default rank of the grammar is 0.
Return value:
On success, returns a rule rank,
and sets the error code to
MARPA_ERR_NONE
.
The rule rank is an integer.
On hard failure, returns -2,
and sets the error code to an appropriate
value, which will never be
MARPA_ERR_NONE
.
Note that -2 is a valid rule rank,
so that when -2 is returned,
the error code is the only way to distinguish
success from failure.
The error code can be determined using
marpa_g_error()
.
See marpa_g_error().
[Mutator] When successful, sets the rank of the rule with ID rule_id to rank and returns rank.
Return value:
On success, returns rank,
which will be an integer,
and sets the error code to
MARPA_ERR_NONE
.
On hard failure, returns -2,
and sets the error code to an appropriate
value, which will never be
MARPA_ERR_NONE
.
Note that -2 is a valid rule rank,
so that when -2 is returned,
the error code is the only way to distinguish
success from failure.
The error code can be determined using
marpa_g_error()
.
See marpa_g_error().
[Accessor] On success, returns a boolean whose value is 1 iff “null ranks high” is set in the rule with ID rule_id. When a rule is created, it has “null ranks high” set.
For more on the
“null ranks high” setting, read the description of
marpa_g_rule_null_high_set()
.
See marpa_g_rule_null_high_set().
Soft fails iff rule_id is well-formed (a non-negative integer), but a rule with that ID does not exist.
Return value: On success, a boolean. On soft failure, -1. On hard failure, -2.
[Mutator] On success,
The “null ranks high” setting affects the ranking of rules with properly nullable symbols on their right hand side. If a rule has properly nullable symbols on its RHS, each instance in which it appears in a parse will have a pattern of nulled and non-nulled symbols. Such a pattern is called a “null variant”.
If the “null ranks high” is set, nulled symbols rank high. If the “null ranks high” is unset is the default), nulled symbols rank low. Ranking of a null variants is done from left-to-right.
Soft fails iff rule_id is well-formed (a non-negative integer), but a rule with that ID does not exist.
Hard fails if the grammar has been precomputed.
Return value: On success, a boolean. On soft failure, -1. On hard failure, -2.
Next: Grammar precomputation, Previous: Sequence methods, Up: Grammar methods [Contents][Index]