complexity in minibuffer (was: (icomplete-vertical-mode): Add support for affixations and, annotations)

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Another pain point in minibuffer is the representation of candidates.
> Sometimes they  are strings, sometimes they are lists of strings with
> prefixes and suffixes, lots of silly "if consp".

I must say I'm not sure what you're referring to here.
So I went searching for `consp` in minibuffer.el, and IIUC you're
talking about the code which takes a set of completions and displays it
in *Completions*.  E.g. the code in `completion--insert-*`.
Is that right?

[ If so, it explains why I wasn't sure what you referred to, since it's
  not part of the code with which I'm familiar ;-)  ]

Indeed, I wonder why we have that.

I know `display-completion-list` is documented to work with lists of
various things (strings, symbols, and lists of strings, IIRC), but
that's an old "feature" of `display-completion-list` that's not used by
the current completion code, AFAIK (and potentially not used by any code
at all).

So we could have a quick loop through the completion candidates at the
entry of `display-completion-list` which converts each candidate to
a plain string and then calls a streamlined `completion--insert-strings`
where we don't need those `consp` any more.
[ And in most cases we could call `completion--insert-strings` directly
  rather than go through the old `display-completion-list`.  ]

WDYT?  Am I missing something?


        Stefan