def la_not_in_set(self, lookahead_exclusions):
if all(len(excl) == 1 for excl in lookahead_exclusions):
return grammar.LookaheadRule(
OrderedFrozenSet(excl[0] for excl in lookahead_exclusions),
False)
raise ValueError("unsupported: lookahead > 1 token, {!r}".format(
lookahead_exclusions))
def la_not_in_set(self, notin, ob, lookahead_exclusions, cb):
assert (notin, ob, cb) == ("<!", '{', '}')
if all(len(excl) == 1 for excl in lookahead_exclusions):
return grammar.LookaheadRule(
OrderedFrozenSet(excl[0] for excl in lookahead_exclusions),
False)
raise ValueError("unsupported: lookahead > 1 token, {!r}".format(
lookahead_exclusions))
""" Functions for loading the ECMAScript lexical and syntactic grammars. """
from jsparagus.ordered import OrderedSet, OrderedFrozenSet
from jsparagus import gen
from .lexer import ECMASCRIPT_FULL_KEYWORDS, ECMASCRIPT_CONDITIONAL_KEYWORDS
from .parse_esgrammar import parse_esgrammar
ECMASCRIPT_LEXICAL_SYNTHETIC_TERMINALS = {
# Theoretically, this should be the set of all Unicode characters, but that
# would take a lot of memory, and in practice, the set is not used.
'SourceCharacter': OrderedFrozenSet([]),
}
ECMASCRIPT_LEXICAL_GOAL_NTS = [
'WhiteSpace',
'InputElementDiv',
'InputElementRegExp',
]
def load_lexical_grammar(filename):
"""Load the ECMAScript lexical grammar."""
with open(filename) as f:
grammar_text = f.read()
g = parse_esgrammar(
grammar_text,
filename=filename,
goals=ECMASCRIPT_LEXICAL_GOAL_NTS,
synthetic_terminals=ECMASCRIPT_LEXICAL_SYNTHETIC_TERMINALS,
terminal_names=ECMASCRIPT_LEXICAL_SYNTHETIC_TERMINALS.keys())
return gen.expand_parameterized_nonterminals(g)
def la_not_in_nonterminal(self, nt):
return grammar.LookaheadRule(OrderedFrozenSet([nt]), False)
def la_ne(self, t):
return grammar.LookaheadRule(OrderedFrozenSet([t]), False)
def la_eq(self, t):
return grammar.LookaheadRule(OrderedFrozenSet([t]), True)
def la_ne(self, ne, t):
assert ne == "!="
return grammar.LookaheadRule(OrderedFrozenSet([t]), False)
def la_eq(self, eq, t):
assert eq == "=="
return grammar.LookaheadRule(OrderedFrozenSet([t]), True)
