Re: cond*

[Ihor Radchenko]

Richard Stallman <rms@gnu.org> writes:

>   > > Since the idea is pattern-matching, I think that a regexp is natural
>   > > as well as more general.  Why not do this?
>
>   > It is not very clear then how to match plain strings for equality.
>
> 1. Instead of writing the string as a literal, write a regexp to match
> only that string.  This is not hard.

This is a bad idea when writing _generic purpose_ code - regexp matching
is _a lot_ slower compared to string comparison. Orders of magnitude.

> 2. Use this constrained variable patern:
>
>    (equal foo "xyz")
>
> It will bind the variable `foo', but you are not required to use it.

I am not a big fan of introducing yet another convention:

Compare

(cond*
 ((match* `("foo?" "bar") '("fo" "bar")) t)) ; => t

(pcase '("fo" "bar")
  (`("foo?" "bar") t)) ; => nil

People familiar with `pcase' will have to keep the above distinction in
mind all the time - a source of potential confusion.

-- 
Ihor Radchenko // yantar92,
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