Also some issues with python_parsertags/gm/2021-09-23T00Z/github.com--lark-parser-lark/0.5.1
@@ -3,6 +3,7 @@ | |||
import re | |||
from .utils import Str, classify | |||
from .common import is_terminal | |||
class LexError(Exception): | |||
pass | |||
@@ -169,3 +170,64 @@ class Lexer(object): | |||
if lex_pos < len(stream): | |||
raise UnexpectedInput(stream, lex_pos, line, lex_pos - col_start_pos) | |||
break | |||
class ContextualLexer: | |||
def __init__(self, tokens, states, ignore=()): | |||
tokens_by_name = {} | |||
for t in tokens: | |||
assert t.name not in tokens_by_name | |||
tokens_by_name[t.name] = t | |||
lexer_by_tokens = {} | |||
self.lexers = {} | |||
for state, accepts in states.items(): | |||
key = frozenset(accepts) | |||
try: | |||
lexer = lexer_by_tokens[key] | |||
except KeyError: | |||
accepts = list(accepts) # For python3 | |||
accepts += ignore | |||
# if '_NEWLINE' in tokens_by_name and '_NEWLINE' not in accepts: | |||
# accepts.append('_NEWLINE') # XXX hack for now | |||
state_tokens = [tokens_by_name[n] for n in accepts if is_terminal(n) and n!='$end'] | |||
lexer = Lexer(state_tokens, ignore=ignore) | |||
lexer_by_tokens[key] = lexer | |||
self.lexers[state] = lexer | |||
self.root_lexer = Lexer(tokens, ignore=ignore) | |||
def lex(self, stream, parser): | |||
lex_pos = 0 | |||
line = 1 | |||
col_start_pos = 0 | |||
newline_types = list(self.root_lexer.newline_types) | |||
ignore_types = list(self.root_lexer.ignore_types) | |||
while True: | |||
lexer = self.lexers[parser.state] | |||
for mre, type_from_index in lexer.mres: | |||
m = mre.match(stream, lex_pos) | |||
if m: | |||
value = m.group(0) | |||
type_ = type_from_index[m.lastindex] | |||
if type_ not in ignore_types: | |||
t = Token(type_, value, lex_pos) | |||
t.line = line | |||
t.column = lex_pos - col_start_pos | |||
if t.type in lexer.callback: | |||
t = lexer.callback[t.type](t) | |||
yield t | |||
if type_ in newline_types: | |||
newlines = value.count(lexer.newline_char) | |||
if newlines: | |||
line += newlines | |||
col_start_pos = lex_pos + value.rindex(lexer.newline_char) | |||
lex_pos += len(value) | |||
break | |||
else: | |||
if lex_pos < len(stream): | |||
raise UnexpectedInput(stream, lex_pos, line, lex_pos - col_start_pos) | |||
break | |||
@@ -1,7 +1,7 @@ | |||
import re | |||
import sre_parse | |||
from .lexer import Lexer | |||
from .lexer import Lexer, ContextualLexer | |||
from .parsers.lalr_analysis import GrammarAnalyzer | |||
from .common import is_terminal, GrammarError | |||
@@ -31,6 +31,25 @@ class LALR(WithLexer): | |||
tokens = list(self.lex(text)) | |||
return self.parser.parse(tokens) | |||
class LALR_ContextualLexer: | |||
def __init__(self, lexer_conf, parser_conf): | |||
self.lexer_conf = lexer_conf | |||
self.parser_conf = parser_conf | |||
self.analyzer = GrammarAnalyzer(parser_conf.rules, parser_conf.start) | |||
self.analyzer.analyze() | |||
d = {idx:t.keys() for idx, t in self.analyzer.states_idx.items()} | |||
self.lexer = ContextualLexer(lexer_conf.tokens, d, ignore=lexer_conf.ignore) | |||
def parse(self, text): | |||
parser = lalr_parser.Parser(self.analyzer, self.parser_conf.callback) | |||
l = self.lexer.lex(text, parser) | |||
return parser.parse(l, True) | |||
class Earley(WithLexer): | |||
def __init__(self, lexer_conf, parser_conf): | |||
WithLexer.__init__(self, lexer_conf) | |||
@@ -82,4 +101,4 @@ class Earley_NoLex: | |||
assert len(res) ==1 , 'Ambiguious Parse! Not handled yet' | |||
return res[0] | |||
ENGINE_DICT = { 'lalr': LALR, 'earley': Earley, 'earley_nolex': Earley_NoLex } | |||
ENGINE_DICT = { 'lalr': LALR, 'earley': Earley, 'earley_nolex': Earley_NoLex, 'lalr_contextual_lexer': LALR_ContextualLexer } |
@@ -7,13 +7,14 @@ class Parser(object): | |||
self.analysis = analysis | |||
self.callbacks = {rule: getattr(callback, rule.alias or rule.origin, None) | |||
for rule in analysis.rules} | |||
self.state = self.analysis.init_state_idx | |||
def parse(self, seq): | |||
def parse(self, stream, set_state=False): # XXX no set_state | |||
stream = iter(stream) | |||
states_idx = self.analysis.states_idx | |||
state_stack = [self.analysis.init_state_idx] | |||
value_stack = [] | |||
i = 0 | |||
def get_action(key): | |||
state = state_stack[-1] | |||
@@ -21,13 +22,8 @@ class Parser(object): | |||
return states_idx[state][key] | |||
except KeyError: | |||
expected = states_idx[state].keys() | |||
try: | |||
token = seq[i] | |||
except IndexError: | |||
assert key == '$end' | |||
token = seq[-1] | |||
raise UnexpectedToken(token, expected, seq, i) | |||
raise UnexpectedToken(token, expected, [], 0) | |||
def reduce(rule, size): | |||
if size: | |||
@@ -48,15 +44,20 @@ class Parser(object): | |||
value_stack.append(res) | |||
# Main LALR-parser loop | |||
while i < len(seq): | |||
action, arg = get_action(seq[i].type) | |||
if action == ACTION_SHIFT: | |||
state_stack.append(arg) | |||
value_stack.append(seq[i]) | |||
i+= 1 | |||
else: | |||
reduce(*arg) | |||
try: | |||
token = next(stream) | |||
while True: | |||
action, arg = get_action(token.type) | |||
if action == ACTION_SHIFT: | |||
state_stack.append(arg) | |||
value_stack.append(token) | |||
if set_state: self.state = arg | |||
token = next(stream) | |||
else: | |||
reduce(*arg) | |||
except StopIteration: | |||
pass | |||
while True: | |||
_action, rule = get_action('$end') | |||
@@ -5,7 +5,7 @@ import logging | |||
from .test_trees import TestTrees | |||
# from .test_selectors import TestSelectors | |||
from .test_parser import TestLalr, TestEarley, TestParsers | |||
from .test_parser import TestLalr, TestEarley, TestLalr_contextual_lexer, TestParsers | |||
# from .test_grammars import TestPythonG, TestConfigG | |||
logging.basicConfig(level=logging.INFO) | |||
@@ -356,11 +356,10 @@ def _make_parser_test(PARSER): | |||
_TestParser.__name__ = _NAME | |||
globals()[_NAME] = _TestParser | |||
for PARSER in ['lalr', 'earley']: | |||
for PARSER in ['lalr', 'earley', 'lalr_contextual_lexer']: | |||
_make_parser_test(PARSER) | |||
if __name__ == '__main__': | |||
unittest.main() | |||