agtest/gen.py

import textwrap
import os
import importlib
from lark import Lark

from agast import *
from agtypeck import *

p = Lark(open("grammar.lark").read(), start="program", parser="lalr")

if __name__ == "__main__":
	with open("arith.ag") as f:
		data = f.read()

	cst = p.parse(data)
	# print("cst", cst)

	trans = Parser()
	ast = trans.transform(cst)
	print("ast", ast)

	res = typecheck(ast)

	if not os.path.exists("gen"):
		os.makedirs("gen")
	with open("gen/arith.py", "w") as f:
		fmt_str = textwrap.dedent("""
			__all__ = ["parse"]
			from typing import Generic, TypeVar, Optional, Callable
			from lark import Lark, Transformer
			T = TypeVar('T')
			class Thunk(Generic[T]):
				''' A thunk represents a value that may be computed lazily. '''
				value: Optional[T]
				def __init__(self, func: Callable[[], T]):
					self.func = func
					self.value = None
				def get(self) -> T:
					if self.value is None:
						self.value = self.func()
					return self.value
			parser = Lark('''start:
			{pd}''')
			class Trans(Transformer[None]):
				pass
			{ex}
			def parse(input: str) -> None:
				print(input)
		""")
		f.write(fmt_str.format(pd=res.parser_data, ex=res.extra))

	mod = importlib.import_module("gen.arith")
	mod.parse("1 + 2 * 3") # type: ignore