bug#60196: 29.0.60; re-builder should read all forms for the rx syntax

[Kai Ma <justksqsf@gmail.com>]

> On Dec 30, 2022, at 20:28, Mattias Engdegård <mattiase@acm.org> wrote:
> 
> The handling of rx input in re-builder is indeed unsatisfactory. We could adopt your proposed solution:
> 
>> Ideally, re-builder should allow users to simply write
>> 
>>    "<i>" (group (*? anychar)) "</i>"
> 
> which would be a definite improvement. We could also accept a Lisp expression that is evaluated, so that you'd write
> 
>    (rx "<i>" (group (*? anychar)) "</i>")
> 
> On the surface this looks more verbose, but since re-builder itself would provide the `(rx )` boilerplate, there wouldn't actually be any more typing.

Good point!  And it is much easier to copy a whole Sexpr.

> The main advantage would be that regexps could be built up from smaller pieces:
> 
>    (rx-let ((spaces (* " "))
>             (identifier (: alpha (* alnum))))
>      (rx identifier spaces "->" spaces identifier))
> 
> Either would be a definite improvement to the current rather strange re-builder behaviour with respect to rx input. Any preference?

I like your proposal better! :-)