I recently discovered the wonderful vtable.el built-in package. As far
as I can tell, vtable is meant to eventually be a drop-in replacement
for tabulated-list-mode (despite (elisp) Tabulated List Mode mentioning
that vtable is geared toward variable pitch fonts, whereas
tabulated-list mode is for monospace fonts) -- please correct me if I am
wrong.
In any case, I noticed that in vtable.el, vtable--sort (which appears to
be where column sorting is implemented) has hard-coded behavior for
sorting, namely, simple numerical and string sorters. I would like to
ask about whether there any plans to add the ability for users to set
custom sorters for their columns. Tabulated-list-mode has a version of
this by setting tabulated-list-format: every column can use its own
sorter.