recipe-286134.py 文件源码

def test_expr(expr, allowed_codes):
    """test_expr(expr) -> codeobj

    Test that the expression contains only the listed opcodes.
    If the expression is valid and contains only allowed codes,
    return the compiled code object. Otherwise raise a ValueError
    """
    try:
        c = compile(expr, "", "eval")
    except:
        raise ValueError, "%s is not a valid expression", expr
    codes = _get_opcodes(c)
    for code in codes:
        if code not in allowed_codes:
            raise ValueError, "opcode %s not allowed" % dis.opname[code]
    return c