readline.py 文件源码

def get_trimmed_history(self, maxlength):
        if maxlength >= 0:
            cut = len(self.history) - maxlength
            if cut < 0:
                cut = 0
        else:
            cut = 0
        return self.history[cut:]

    # --- simplified support for reading multiline Python statements ---

    # This duplicates small parts of pyrepl.python_reader.  I'm not
    # reusing the PythonicReader class directly for two reasons.  One is
    # to try to keep as close as possible to CPython's prompt.  The
    # other is that it is the readline module that we are ultimately
    # implementing here, and I don't want the built-in raw_input() to
    # start trying to read multiline inputs just because what the user
    # typed look like valid but incomplete Python code.  So we get the
    # multiline feature only when using the multiline_input() function
    # directly (see _pypy_interact.py).