interactiveshell.py 文件源码

def get_default_editor():
    try:
        ed = os.environ['EDITOR']
        if not PY3:
            ed = ed.decode()
        return ed
    except KeyError:
        pass
    except UnicodeError:
        warn("$EDITOR environment variable is not pure ASCII. Using platform "
             "default editor.")

    if os.name == 'posix':
        return 'vi'  # the only one guaranteed to be there!
    else:
        return 'notepad' # same in Windows!

# conservatively check for tty
# overridden streams can result in things like:
# - sys.stdin = None
# - no isatty method