def main():
argparser = argparse.ArgumentParser(
description=inspect.getdoc(sys.modules[__name__]))
argparser.add_argument('json_file',
nargs='?',
default='grammar/src/grammar.json',
help='file holding the JSON form of the grammar')
argparser.add_argument('-v',
'--verbose',
help='increase output verbosity',
action="store_true")
argparser.add_argument(
'-ll',
help='compute LL(1) parser table and associated conflicts',
action="store_true")
argparser.add_argument(
'-lalr',
help='compute LALR(1) parser table and associated conflicts',
action="store_true")
argparser.add_argument('-lr',
help='compute LR(1) item sets',
action="store_true")
argparser.add_argument('-limit',
type=int,
help='limit on number of LALR(1) item sets')
args = argparser.parse_args()
with open(args.json_file) as infile:
json_text = "".join(infile.readlines())
g = Grammar.Load(json_text, 'translation_unit')
if args.lalr:
print("=Grammar:\n")
print(g.pretty_str())
parse_table = g.LALR1(max_item_sets=args.limit)
parse_table.write(sys.stdout)
if parse_table.has_conflicts():
sys.exit(1)
sys.exit(0)
if args.lr:
lr1_itemsets = g.LR1_ItemSets()
for IS in lr1_itemsets:
print("\n{}".format(str(IS)))
sys.exit(0)
elif args.ll:
(table, conflicts) = g.LL1()
for key, reduction in table.items():
(non_terminal, token) = key
print("{} {}: {}".format(non_terminal, str(token), str(reduction)))
for (lhs, terminal, action, action2) in conflicts:
print("conflict: {}->{}: {} {}".format(lhs, terminal, action,
action2))
if len(conflicts) > 0:
sys.exit(1)
else:
if args.verbose:
g.dump()
else:
print(g.pretty_str())
sys.exit(0)
