RE: should query-replace-regexp-eval be in the manual?

[Drew Adams]

> >> Basically it has been my experience that query-replace-regexp-eval
> >> is a nice idea, but in practice quite unusable.  \, achieves a
> >> similar purpose but with a much more convenient interface.
> >
> > To get back to the original question: since \, has all of the
> > functionality of query-replace-regexp-eval with a more convenient
> > interface, query-replace-regexp-eval could be considered obsolete or
> > at least obscure.
> >
> > Since we tell people how to do the same thing more flexibly with \, I
> > don't think that query-replace-regexp-eval deserves a place in the
> > manual.  It would be a lot of additional explanation without any
> > conceivable benefit to the user.
>
> After reading this I think it would be a good idea to tell in the doc
> string for query-replace-regexp-eval to use query-replace-regexp + \
> instead.

There is never any sense in saying to use something else instead, unless it
has truly been deprecated.

The question is whether this has a use on its own, which would keep it from
being deprecated. In that case, the doc string should explain what that use
is.

I think that it probably does merit keeping. It has the advantage of simpler
syntax, for the use case to which it applies: replacement by an evaled sexp
(only).

IOW:
- `query-regexp-replace' is best all 'round: flexible, general
- `query-regexp-replace-eval' has a simpler UI when you are
  using only eval-replacement - no need to use `\,...'.