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Re: Update of pcase docs for the elisp manual


From: John Wiegley
Subject: Re: Update of pcase docs for the elisp manual
Date: Thu, 28 Jan 2016 17:28:30 -0800
User-agent: Gnus/5.130014 (Ma Gnus v0.14) Emacs/24.5 (darwin)

>>>>> Eli Zaretskii <address@hidden> writes:

>> > AFAIU, your division into logical and literal was different from the
>> > division between UPatterns and QPatterns. That's why I didn't use those
>> > terms.
>> 
>> Could you explain a bit more how they were different? Such variance was
>> intended.

> Sorry, I didn't keep your text after I finished working on this. If you send
> it to me again, I will try to explain.

All I meant is, as far as I can tell, UPattern = logical, and QPattern =
literal, without any variation. So isn't it just a name substitution, and
isn't that better than UPattern and QPattern?

>> Ah, so they are syntactical simpler, but not semantically simpler.

> No, they are also semantically different: they allow more generalized
> matching rules.

Different yes, but that's not simpler.  The rules for understanding what a
quoted pattern will do are incredibly trivial: it matches per eq with the
scrutinee at that position.  The rules of understanding what a UPattern will
do are far more complicated, and can even be extended use pcase-defmacro.

>> Hmm. Maybe we should drop the statement about simplicity and just say we're
>> presenting UPatterns first.

> Like I said: I don't own the manual...

> I do wonder why these minor nits trigger such a large portion of the
> comments. They are there to make the text easier to read, so it isn't too
> dry. If people dislike that style, it's fine with me to delete those parts,
> but what about "the meat"? Did I succeed to write something that can be
> studied and learned from?

Anything, really, is a move forward from what we had before. It's sufficient
for 25.1 in my opinion.

-- 
John Wiegley                  GPG fingerprint = 4710 CF98 AF9B 327B B80F
http://newartisans.com                          60E1 46C4 BD1A 7AC1 4BA2



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