Recently, I've been preparing to add tcsh support to argc and argc-completions.

complete argc 'p@*@`echo "$COMMAND_LINE'"''"'" | xargs argc --argc-compgen tcsh ""`@@';

argc --argc-compgen may generate words containing spaces, how to make it work?

Testing can be simplified as follows:

complete cmd 'p@*@`cat /tmp/file`@@'

The content of /tmp/file maybe:

Coldark-Cold
Monokai Extended
Solarized (dark)
Solarized (light)