ast.py 文件源码

def __init__(self, code, **exception_kwargs):
        m = re.match(r'^(\w+)(?:\s+(.*?))?:\s*(#|$)', code.strip(), re.S)
        if not m:
            raise exceptions.CompileException(
                "Fragment '%s' is not a partial control statement" %
                code, **exception_kwargs)
        if m.group(3):
            code = code[:m.start(3)]
        (keyword, expr) = m.group(1, 2)
        if keyword in ['for', 'if', 'while']:
            code = code + "pass"
        elif keyword == 'try':
            code = code + "pass\nexcept:pass"
        elif keyword == 'elif' or keyword == 'else':
            code = "if False:pass\n" + code + "pass"
        elif keyword == 'except':
            code = "try:pass\n" + code + "pass"
        elif keyword == 'with':
            code = code + "pass"
        else:
            raise exceptions.CompileException(
                "Unsupported control keyword: '%s'" %
                keyword, **exception_kwargs)
        super(PythonFragment, self).__init__(code, **exception_kwargs)