Re: [PATCH] `completing-read`: Add `group-function` support to completion metadata (REVISED PATCH)

[Daniel Mendler]

On 4/29/21 7:07 PM, Stefan Monnier wrote:
> The purpose of the `group-function` when called with a non-nil
> `transform` arg is not to *add* text but on the contrary to make the
> entries shorter (presumably by removing text shared by all elements of
> the group and made redundant by the group name being printed as
> a "section title").
> 
> So the purpose of `affixation/annotation-function` and `group-function`
> seem orthogonal (tho we should be careful to make them work together:
> the affixation/annotation function will usually need the "full name" in
> order to decide what to add, but that the thing should be added to the
> text as shortened by `group-function`).

Exactly, the grouping and affixation transformation functions are
orthogonal and should not be conflated. The patch I provided ensures
that the two features work well together - in both cases, with grouping
enabled and disabled.

Daniel