interpreter_utils.py

import sys
import ast
import inspect


def _arg_name(name):
    """
    :param str name:
    :return:
    """
    if sys.version_info[0] == 2:
        return ast.Name(id=name, ctx=ast.Param())
    return ast.arg(arg=name, annotation=None)


def _ast_bin_op_to_ast_expression(op):
    if inspect.isclass(op):
        op = op()
    assert isinstance(op, ast.operator)
    args = ast.arguments(
        posonlyargs=[], args=[_arg_name("a"), _arg_name("b")],
        vararg=None, kwonlyargs=[], kw_defaults=[], kwarg=None, defaults=[])
    body = ast.BinOp(
        left=ast.Name(id="a", ctx=ast.Load()), op=op,
        right=ast.Name(id="b", ctx=ast.Load()))
    l = ast.Lambda(args=args, body=body)
    expr = ast.Expression(body=l)
    return expr


def compile_expr_to_code(expr):
    ast.fix_missing_locations(expr)
    code = compile(expr, "<_astOpToFunc>", "eval")
    return code


def ast_bin_op_to_func(op):
    expr = _ast_bin_op_to_ast_expression(op)
    code = compile_expr_to_code(expr)
    f = eval(code)
    return f