16.9. rlcompleter — Completion function for GNU readline

The rlcompleter module defines a completion function suitable for the readline module by completing valid Python identifiers and keywords.

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.

Example:

>>> 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. A user can add the following lines to his or her initialization file (identified by the PYTHONSTARTUP environment variable) to get automatic Tab completion:

try:
    import readline
except ImportError:
    print("Module readline not available.")
else:
    import rlcompleter
    readline.parse_and_bind("tab: complete")

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

16.9.1. Completer Objects

Completer objects have the following method:

Completer.complete(text, state)

Return the stateth completion for text.

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.

Table Of Contents

Previous topic

16.8. readline — GNU readline interface

Next topic

17. Interprocess Communication and Networking

This Page