cctrlw 0.4

Configurable Ctrl-W algorithm, xontrib and CLI.

Configurable Ctrl-W (see gifs to understand what that means).

# TODO: gifs

This project addresses the pitfalls of xonsh (a brilliant project btw) builtin Ctrl-W functionality.

What exactly was wrong? There was no way to configure which characters are considered equivalent (and hence, to be deleted on a Ctrl-W keystoke). Say you wanted to edit a ‘cmd a/very/long/path’ and press a C-W. Then everything till space is removed, which often is not the desired behaviour.

Ok, so how to configure such a thing? Mathematically such configuration is equivalent to a partition of the set of all characters. In terms of implementation, disjoint set union data structure can be used to maintain partitions. Using a DSU is not really a requirement; however it turns out to be the simplest and cleanest implementation.

See docstring for load_partitions in cctrlw/algo.py to understand the approach used to define partitions.

Default cw_modes.json defines the following partitions:

• S: singletons

• ldu: {{a..z}, {0..9}, {A..Z}}

• ldup: compared to ldu: elements of {!”#$%&’()*+,-./:;<=>?@[]^_`{|}~} are now equivalent

• Ldp: compared to ldup: lower and upper letters are now merged

• Ap: compared to Ldp: digits and letters are now merged

• W: compared to Ap: digits and punctuation are merged

Xonsh default Ctrl-W corresponds to W, hence the name.

In terms of actual usage this module provides a CLI and a xontrib for use with xonsh:

• CLI: run python -m cctrlw.cli -h for details.

• Xontrib: add xontrib load xonsh_cctrlw to your .xonshrc. Then you can modify your config by setting $CW_MODE and $CW_CONFIG environment variables. Defaults are $CW_MODE = ‘Ap’ and $CW_CONFIG = ‘<package location>/cw_modes.json’.