Re: Question on pcase

[Alan Mackenzie <acm@muc.de>]

Hello, Stephen.

On Sat, Oct 24, 2015 at 09:10:49PM +0200, Stephen Berman wrote:
> On Sat, 24 Oct 2015 17:47:19 +0000 Alan Mackenzie <acm@muc.de> wrote:

> >> >  ;; This is a pattern form that allows you to match a pattern PAT
> >> >  ;; against an _arbitrary_ expression EXP.  This is not special,
> >> > -;; matching PAT is done as you have learned, just against the EXP you
> >> > +;; matching PAT is done as you have learned, just on the EXP you
> >> >  ;; specify there, and not the EXPRESSION given to pcase at top level.

> >> Why replace "against" with "on" here but not in the preceding line?  I
> >> think "against" is usual in this context.  A somewhat better formulation
> >> is this, IMO: "The only difference from the pattern matching you have
> >> learned is that PAT is matched against the EXP you specify here..."

> > Oh, no!  This is complicated, too.  

> It doesn't strike me as more complicated than the original, just a bit
> less stilted (to my ears).

Sorry for that.  I meant the _topic_ is complicated.

> >                                     Perhaps the best preposition for
> > "match" here is "with", on the grounds that harmony is expected rather
> > than a fight.  You might match one sporting team against another, but
> > you'd match the colour of an item of clothing with that of another.  Or
> > something like that.

> "Match with" sounds out of place here.  I think "match against" is
> pretty much standard in the context of pattern matching in formal or
> programming languages; cf. these quotes (among many similar) from
> Friedl's _Mastering Regular Expressions_ (3rd ed): 

Maybe.  I confess here to being personally irritated by "match against".
I don't know why.

But I honestly think it's time for our discussion to cease.  We've
unwittingly descended into bikeshedding, and we're not going to be
helping Michael Heerdegen much with it.  But thanks for the discussion
anyway!

[ Paragraphs snipped, but read and largely accepted. ]

> Steve Berman

-- 
Alan Mackenzie (Nuremberg, Germany).