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"""Quick and dirty code generator."""
from story3.grammar import Rule
HEADER = """\
# This is @generated code; do not edit!
from token import NAME, NUMBER, STRING, NEWLINE, ENDMARKER
from story3.memo import memoize
from story3.node import Node
from story3.parser import Parser
"""
import sys
def generate(rules, stream=None):
if stream:
sys.stdout = stream
print(HEADER)
generate_parser_class(rules)
def generate_parser_class(rules):
print(f"class ToyParser(Parser):")
for rule in rules:
print()
print(f" @memoize")
print(f" def {rule.name}(self):")
print(f" pos = self.mark()")
for alt in rule.alts:
items = []
print(f" if (True")
for item in alt:
if item[0] in ('"', "'"):
print(f" and self.expect({item})")
else:
var = item.lower()
if var in items:
var += str(len(items))
items.append(var)
if item.isupper():
print(" " +
f"and ({var} := self.expect({item}))")
else:
print(f" " +
f"and ({var} := self.{item}())")
print(f" ):")
print(f" " +
f"return Node({rule.name!r}, [{', '.join(items)}])")
print(f" self.reset(pos)")
print(f" return None")
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