rlcompleter — Completion function for GNU readline

Source code: Lib/rlcompleter.py

The rlcompleter module defines a completion function suitable to be passed to set_completer() in the readline module.

When this module is imported on a Unix platform with the readline module available, an instance of the Completer class is automatically created and its complete() method is set as the readline completer. The method provides completion of valid Python identifiers and keywords.


>>> import rlcompleter
>>> import readline
>>> readline.parse_and_bind("tab: complete")
>>> readline. <TAB PRESSED>
readline.__doc__          readline.get_line_buffer(  readline.read_init_file(
readline.__file__         readline.insert_text(      readline.set_completer(
readline.__name__         readline.parse_and_bind(
>>> readline.

The rlcompleter module is designed for use with Python’s interactive mode. Unless Python is run with the -S option, the module is automatically imported and configured (see Readline configuration).

On platforms without readline, the Completer class defined by this module can still be used for custom purposes.

class rlcompleter.Completer

Completer objects have the following method:

complete(text, state)

Return the next possible completion for text.

When called by the readline module, this method is called successively with state == 0, 1, 2, ... until the method returns None.

If called for text that doesn’t include a period character ('.'), it will complete from names currently defined in __main__, builtins and keywords (as defined by the keyword module).

If called for a dotted name, it will try to evaluate anything without obvious side-effects (functions will not be evaluated, but it can generate calls to __getattr__()) up to the last part, and find matches for the rest via the dir() function. Any exception raised during the evaluation of the expression is caught, silenced and None is returned.