Add option to control setting of completion-in-region-function

[tsdh]

I just started using selectrum with prescient and I like it very much. However, one thing I would like to disable is the feature that normal in-buffer completion (completion-at-point-functions) is now also transferred into the minibuffer. How can I do that?

As an example of what I mean, here's a recipe for shell:

1. M-x shell RET
2. cd ~/R<TAB>

Now the path is going to be read from the minibuffer instead being normally TAB-completed in place (with possibly a *Completions* buffer if there are many choices starting with the current prefix or cycling if there are just a few).

[tsdh]

Ah, to answer my own question: That does the trick.

(selectrum-mode 1)
  (setq-default completion-in-region-function
                selectrum--old-completion-in-region-function)

Maybe there should be a variable controlling if selectrum should activate itself for in-buffer completion, so I let that issue open for now.

[clemera]

Having an option for this is a good idea, icomplete and ivy have this as well. BTW file completions act like find-file with selectrum so you can navigate through the path levels via completion.

[clemera]

If there is only one file candidate the minibuffer shouldn't open and the result should be inserted in place, we have to update that, too.

[tsdh]

@clemera Yes, that in-buffer file completion completes the whole path in one go is actually nice but still I'm distracted by the input switching from one very specific position in a buffer to the bottom left minibuffer. That might be mitigated with a posframe, though, if you need ideas for things to play with. ;-)

[clemera]

There is also mini-frame but it doesn't feature an "at point" option AFAIK.

[clemera]

If there is only one file candidate the minibuffer shouldn't open and the result should be inserted in place, we have to update that, too.

After some experimentation I think it's better to pop to the minibuffer even if there is only one candidate (for file completion). Inserting the single candidate immediately will only help if you wanted to stop completion there but I think it is more common to navigate through several path levels and in this case the current behaviour has an advantage.

[clemera]

When #261 got merged you only get prompted if there are multiple candidates for the current input.

[clemera]

As mentioned over there I also added the option you asked for named selectrum-complete-in-buffer.

[clemera]

Inserting the single candidate immediately will only help if you wanted to stop completion there but I think it is more common to navigate through several path levels and in this case the current behaviour has an advantage.

After reconsideration I think the behaviour of #261 is a good compromise, pressing TAB again will let you drop into the minibuffer after single candidate insertion if needed. This is also more similar to how default completion works and is generally better if the single candidate is a file and not directory.

[clemera]

Should be fixed by #261?

[tsdh]

@clemera The new option selectrum-complete-in-buffer does the trick for me. Thanks!