"""Real-world parsers using the SimpleParse EBNF"""
from simpleparse import baseparser,simpleparsegrammar,common
class Parser( baseparser.BaseParser ):
"""EBNF-generated Parsers with results-handling
The Parser is a two-stage object:
Passed an EBNF definition during initialisation,
it compiles the definition into a tagging table
(which in turn requires creating a tagging table
for parsing the EBNF).
You then call the parser's parse method to
perform the actual parsing of your data, with the
parser passing the results to your processor object
and then back to you.
"""
def __init__(
self, declaration, root='root',
prebuilts=(),
definitionSources=common.SOURCES,
):
"""Initialise the parser, creating the tagging table for it
declaration -- simpleparse ebnf declaration of the language being parsed
root -- root production used for parsing if none explicitly specified
prebuilts -- sequence of (name,value) tuples with prebuilt tables, values
can be either objectgenerator EventToken sub-classes or TextTools
tables
definitionSources -- dictionaries of common constructs for use
in building your grammar
"""
self._rootProduction = root
self._declaration = declaration
self._generator = simpleparsegrammar.Parser(
declaration, prebuilts,
definitionSources = definitionSources,
).generator
def buildTagger( self, production=None, processor=None):
"""Get a particular parsing table for a particular production"""
if production is None:
production = self._rootProduction
if processor is None:
processor = self.buildProcessor()
return self._generator.buildParser(
production,
methodSource=processor,
)
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