Re: Quality of life improvements to macroexp.el

[Thuna <thuna.cing@gmail.com>]

Mattias Engdegård <mattias.engdegard@gmail.com> writes:

> Hello Thuna,
>
>> I was just looking into using macroexp.el and found some features that I
>> felt were lacking.  These were: 1. accepting multiple forms in
>> `macroexp-if' and `macroexp-let*', 2. flattening of `progn's in
>> `macroexp-progn' and `macroexp-unprogn', 3. getting rid of branches in
>> `macroexp-if' in case the TEST is constant (and consequently a way to
>> tell whether a constant form is nil or non-nil).  I've went through the
>> rest of macroexp.el and haven't found anything else that stood out,
>> though I might change my mind as I keep using it.
>
> If they aren't in Emacs, it may be because nobody else has felt the need for them.
>
> Perhaps there is a misunderstanding of macros like `macroexp-progn`: their purpose is not to produce 'short' or 'neat' output, but to avoid consing more than necessary during the macro-expansion phase. It's just a (compilation) performance hack, and not a very important one either.

I expect that a non-insignificant number of people use packages such as
macrostep (or plain-old `macroexpand-1') to view expansions of forms
while debugging issues.  To that end I would consider keeping a 'neat'
output a desirable if not significant goal.  Of course, it should not
come at massive costs, so I would consider my sample implementations of
`macroexp-progn' and `macroexp-unprogn' as discardable, given the heavy
recursion.