def build(self):
g = Grammar(self.tokens)
for level, (assoc, terms) in enumerate(self.precedence, 1):
for term in terms:
g.set_precedence(term, assoc, level)
for prod_name, syms, func, precedence in self.productions:
g.add_production(prod_name, syms, func, precedence)
g.set_start()
for unused_term in g.unused_terminals():
warnings.warn(
"Token %r is unused" % unused_term,
ParserGeneratorWarning,
stacklevel=2
)
for unused_prod in g.unused_productions():
warnings.warn(
"Production %r is not reachable" % unused_prod,
ParserGeneratorWarning,
stacklevel=2
)
g.build_lritems()
g.compute_first()
g.compute_follow()
# cache_dir = AppDirs("rply").user_cache_dir
cache_file = cache_dir = 'zgrammar.txt'
table = None
if os.path.exists(cache_file):
with open(cache_file, 'r') as f:
data = json.load(f)
if self.data_is_valid(g, data):
table = LRTable.from_cache(g, data)
if table is None:
table = LRTable.from_grammar(g)
serial = self.serialize_table(table)
try:
with open(cache_file, "w") as f:
json.dump(serial, f)
except IOError as e:
print(e.message)
if table.sr_conflicts:
warnings.warn(
"%d shift/reduce conflict%s" % (
len(table.sr_conflicts),
"s" if len(table.sr_conflicts) > 1 else ""
),
ParserGeneratorWarning,
stacklevel=2,
)
if table.rr_conflicts:
warnings.warn(
"%d reduce/reduce conflict%s" % (
len(table.rr_conflicts),
"s" if len(table.rr_conflicts) > 1 else ""
),
ParserGeneratorWarning,
stacklevel=2,
)
return LRParser(table, self.error_handler)
