Re: Disabling imenu default of thing-at-point

[Felipe Ochoa <felipe.nospam.ochoa@gmail.com>]

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---------- Forwarded message ----------
From: Drew Adams <drew.adams@oracle.com>
Date: 24 July 2017 at 20:24
Subject: RE: Disabling imenu default of thing-at-point
To: Felipe Ochoa <felipe.nospam.ochoa@gmail.com>
> > Sounds like Ido (or Ido Ubiquitous) needs to be fixed.  There
> > should not be a problem with providing a default value, even
> > when that default value might not always be helpful.

> I think this could also be an option, but note that ido follows
> completing-read-default in its handling of invalid defaults. E.g.,
> evaluate the following and hit RET without selecting anything:

> (completing-read-default "Complete: " '("abc" "def" "ghi") nil t nil nil
"jkl")

> The result will be "jkl".

That's the case also for the Imenu code you cited, no? NAME is the default
value to `completing-read', and you get it in that case by hitting RET with
no input.

And there is nothing "invalid" about the "jkl" value.

`completing-read' has multiple uses. It is not just for picking one of a
set of completion candidates. When `t' is specified as the REQUIRED arg it
means that either (a) one of those candidates must be picked *or* (2) the
default value can be picked. The list of candidates might be predefined,
and the default value might be computed dynamically (e.g. thing at point),
for example.
> One thing that cannot be fixed within ido (or completing-read)
> is the prompt. Currently all users see "Index item (default %s): ",
> even when the default is bogus, instead of "Index item: ".

Why is it bogus? If a different behavior were desired, where a user could
not pick the default value but had to pick one of the completion
candidates, then the `completing-read' call would be different.



Perhaps Ido Ubiquitous does not provide for or handle such a use case (?).
But it is a common and useful use case of `completing-read'.


> > > It breaks everyone's ability to pick up what was previously the
> > > default value as a default value.
> > >
> > > > -      (setq name (or (imenu-find-default name
prepared-index-alist) name)))
> > > > +      (setq name (imenu-find-default name prepared-index-alist)))
> > > >      (cond (prompt)
> > > >         ((and name (imenu--in-alist name prepared-index-alist))
> > > >          (setq prompt (format "Index item (default %s): " name)))
> > >
> > > If you make that change then what is the sense of binding `name' to
> > > `(thing-at-point 'symbol)' in the first place?  It's only purpose
> > > could then be to return a string so that `imenu-find-default' is
> > > used at all.  This doesn't make any sense (to me).


>
> The code does not do away with defaults. To me, the new approach
> would mean in words:
>
> 1. Grab the symbol at point.
> 2. Check if it matches one of the items in the index.
> 3. If so, offer it as a default. Otherwise, ignore it.


I understand that that's what you proposed. (There's a simpler way to code
that, if that's what's desired.) But is that what was intended for the
Imenu code? Does it make no sense (in this case) for a user to pick the
default value if it is not one of the completion candidates?

On 25 July 2017 at 11:05, Felipe Ochoa <felipe.nospam.ochoa@gmail.com>
wrote:

> (Apologies, forgot to CC the list)
>
>
> > Sounds like Ido (or Ido Ubiquitous) needs to be fixed.  There
> > should not be a problem with providing a default value, even
> > when that default value might not always be helpful.
>
> I think this could also be an option, but note that ido follows
> completing-read-default in its handling of invalid defaults. E.g.,
> evaluate the following and hit RET without selecting anything:
>
> (completing-read-default
>  "Complete: " '("abc" "def" "ghi")
>  nil t nil nil "jkl")
>
> The result will be "jkl".
>
> One thing that cannot be fixed within ido (or completing-read)
> is the prompt. Currently all users see "Index item (default %s): ",
> even when the default is bogus, instead of "Index item: ".
>
> > It breaks everyone's ability to pick up what was previously the
> > default value as a default value.
> >
> > > -      (setq name (or (imenu-find-default name prepared-index-alist)
> name)))
> > > +      (setq name (imenu-find-default name prepared-index-alist)))
> > >      (cond (prompt)
> > >         ((and name (imenu--in-alist name prepared-index-alist))
> > >          (setq prompt (format "Index item (default %s): " name)))
> >
> > If you make that change then what is the sense of binding `name' to
> > `(thing-at-point 'symbol)' in the first place?  It's only purpose
> > could then be to return a string so that `imenu-find-default' is
> > used at all.  This doesn't make any sense (to me).
>
> The code does not do away with defaults. To me, the new approach
> would mean in words:
>
> 1. Grab the symbol at point.
> 2. Check if it matches one of the items in the index.
> 3. If so, offer it as a default. Otherwise, ignore it.
>
>
>

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