pydoc.py 文件源码

def getpager():
    """Decide what method to use for paging through text."""
    if type(sys.stdout) is not types.FileType:
        return plainpager
    if not sys.stdin.isatty() or not sys.stdout.isatty():
        return plainpager
    if 'PAGER' in os.environ:
        if sys.platform == 'win32': # pipes completely broken in Windows
            return lambda text: tempfilepager(plain(text), os.environ['PAGER'])
        elif os.environ.get('TERM') in ('dumb', 'emacs'):
            return lambda text: pipepager(plain(text), os.environ['PAGER'])
        else:
            return lambda text: pipepager(text, os.environ['PAGER'])
    if os.environ.get('TERM') in ('dumb', 'emacs'):
        return plainpager
    if sys.platform == 'win32' or sys.platform.startswith('os2'):
        return lambda text: tempfilepager(plain(text), 'more <')
    if hasattr(os, 'system') and os.system('(less) 2>/dev/null') == 0:
        return lambda text: pipepager(text, 'less')

    import tempfile
    (fd, filename) = tempfile.mkstemp()
    os.close(fd)
    try:
        if hasattr(os, 'system') and os.system('more "%s"' % filename) == 0:
            return lambda text: pipepager(text, 'more')
        else:
            return ttypager
    finally:
        os.unlink(filename)