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The basic step accessors are so called because their information is basic to the stack manipulation. The basic step accessors are implemented as macros. They always succeed.
For a MARPA_STEP_RULE
step,
returns the stack location where the value of first child
can be found.
For a MARPA_STEP_RULE
step,
returns the stack location where the value of the last child
can be found.
For MARPA_STEP_RULE
,
MARPA_STEP_TOKEN
,
and MARPA_STEP_NULLING_SYMBOL
steps,
returns the stack location where the result of the semantics
should be placed.
For the
MARPA_STEP_RULE
step,
returns the ID of the rule.
Returns the current step type:
MARPA_STEP_TOKEN
,
MARPA_STEP_RULE
,
etc.
Usually not needed since this is also the return value of
marpa_v_step()
.
For the MARPA_STEP_NULLING_SYMBOL
step,
returns the ID of the symbol.
The value returned is the same as that
returned by the
marpa_v_token()
macro.
For the MARPA_STEP_TOKEN
step,
returns the ID of the token.
The value returned is the same as that
returned by the
marpa_v_symbol()
macro.
For the MARPA_STEP_TOKEN
step,
returns the integer which is
(or which represents)
the value of the token.