* Adding assoc-delete-all / rassoc-delete-all
@ 2014-04-17 11:39 Tassilo Horn
2014-04-17 11:55 ` Thorsten Jolitz
2014-04-17 15:17 ` Teemu Likonen
0 siblings, 2 replies; 8+ messages in thread
From: Tassilo Horn @ 2014-04-17 11:39 UTC (permalink / raw)
To: emacs-devel
Hi all,
I've just got aware of `assq-delete-all' which could be a convenient
function to get rid of some entry in an alist. However, if the alist
entries start with a string, you need to use something awkward like
(assq-delete-all
(car (assoc "Biber" TeX-command-list))
TeX-command-list)
so that the string "Biber" is not only equal but identical.
So I'm voting for adding a function `assoc-delete-all' which is just
like `assq-delete-all' except that it does the comparison with `equal'
instead of `eq'. Then the above becomes just
(assoc-delete-all "Biber" TeX-command-list)
For symmetry, I'd also add `rassoc-delete-all' to the existing
`rassq-delete-all'.
Would that be ok?
Bye,
Tassilo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Adding assoc-delete-all / rassoc-delete-all
2014-04-17 11:39 Adding assoc-delete-all / rassoc-delete-all Tassilo Horn
@ 2014-04-17 11:55 ` Thorsten Jolitz
2014-04-17 12:29 ` Stefan Monnier
2014-04-17 12:35 ` Tassilo Horn
2014-04-17 15:17 ` Teemu Likonen
1 sibling, 2 replies; 8+ messages in thread
From: Thorsten Jolitz @ 2014-04-17 11:55 UTC (permalink / raw)
To: emacs-devel
Tassilo Horn <tsdh@gnu.org> writes:
> So I'm voting for adding a function `assoc-delete-all' which is just
> like `assq-delete-all' except that it does the comparison with `equal'
> instead of `eq'.
Reminds me of the many times I wished there would be a
,--------------------------------------------------------
| case is an alias for `cl-case' in `cl.el'.
|
| (case EXPR (KEYLIST BODY...)...)
|
| Eval EXPR and choose among clauses on that value. [...]
| Key values are compared by `eql'.
`--------------------------------------------------------
that does comparison with `equal' too (or does it exist and I just
missed it?).
--
cheers,
Thorsten
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Adding assoc-delete-all / rassoc-delete-all
2014-04-17 11:55 ` Thorsten Jolitz
@ 2014-04-17 12:29 ` Stefan Monnier
2014-04-17 13:36 ` Thorsten Jolitz
2014-04-17 12:35 ` Tassilo Horn
1 sibling, 1 reply; 8+ messages in thread
From: Stefan Monnier @ 2014-04-17 12:29 UTC (permalink / raw)
To: Thorsten Jolitz; +Cc: emacs-devel
> ,--------------------------------------------------------
> | case is an alias for `cl-case' in `cl.el'.
> |
> | (case EXPR (KEYLIST BODY...)...)
> |
> | Eval EXPR and choose among clauses on that value. [...]
> | Key values are compared by `eql'.
> `--------------------------------------------------------
> that does comparison with `equal' too (or does it exist and I just
> missed it?).
Not quite what you're asking, but `pcase' uses `equal' to compare strings.
Stefan
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Adding assoc-delete-all / rassoc-delete-all
2014-04-17 11:55 ` Thorsten Jolitz
2014-04-17 12:29 ` Stefan Monnier
@ 2014-04-17 12:35 ` Tassilo Horn
2014-04-17 13:15 ` Stefan Monnier
2014-04-17 13:40 ` Thorsten Jolitz
1 sibling, 2 replies; 8+ messages in thread
From: Tassilo Horn @ 2014-04-17 12:35 UTC (permalink / raw)
To: Thorsten Jolitz; +Cc: emacs-devel
Thorsten Jolitz <tjolitz@gmail.com> writes:
> Reminds me of the many times I wished there would be a
>
> ,--------------------------------------------------------
> | case is an alias for `cl-case' in `cl.el'.
> |
> | (case EXPR (KEYLIST BODY...)...)
> |
> | Eval EXPR and choose among clauses on that value. [...]
> | Key values are compared by `eql'.
> `--------------------------------------------------------
Strange that it compares with `eql'. Doesn't `eql' only allow comparing
floating point values in addition to what's allowed by `eq'? And floats
don't seem to be reasonable candidates for a `case' distinction...
> that does comparison with `equal' too (or does it exist and I just
> missed it?).
No, I don't think there is. But I think here a more versatile macro
would be better than hard-coding another version with the test fixed to
`equal' [1]. For example, Clojure has `condp' which is similar to
`case' but allows to specify the predicate.
(condp #'equal x
"Foo" :foo
1 :one
17 :seventeen
:neither-foo-one-or-seventeen)
Bye,
Tassilo
[1] That's a bit different for `assoc-delete-all' because the names
`assq' and `assoc' are traditionally associated with `eq' and
`equal'.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Adding assoc-delete-all / rassoc-delete-all
2014-04-17 12:35 ` Tassilo Horn
@ 2014-04-17 13:15 ` Stefan Monnier
2014-04-17 13:40 ` Thorsten Jolitz
1 sibling, 0 replies; 8+ messages in thread
From: Stefan Monnier @ 2014-04-17 13:15 UTC (permalink / raw)
To: Thorsten Jolitz; +Cc: emacs-devel
> Strange that it compares with `eql'. Doesn't `eql' only allow comparing
> floating point values in addition to what's allowed by `eq'?
Common-Lisp simply uses `eql' by default "everywhere". That's because
the semantics of `eq' is pretty weird, really: if it weren't for `eq'
you could never tell the difference between two identical floats. So in
many ways, `eq' is a mistake which lets details of implementation
seep through.
Oh, and IIUC `eql' is also different from `eq' on all other immutable
objects (e.g. bignums).
> And floats don't seem to be reasonable candidates for a `case'
> distinction...
Indeed, but comparing their addresses is even less desirable.
Stefan
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Adding assoc-delete-all / rassoc-delete-all
2014-04-17 12:29 ` Stefan Monnier
@ 2014-04-17 13:36 ` Thorsten Jolitz
0 siblings, 0 replies; 8+ messages in thread
From: Thorsten Jolitz @ 2014-04-17 13:36 UTC (permalink / raw)
To: emacs-devel
Stefan Monnier <monnier@IRO.UMontreal.CA> writes:
>> ,--------------------------------------------------------
>> | case is an alias for `cl-case' in `cl.el'.
>> |
>> | (case EXPR (KEYLIST BODY...)...)
>> |
>> | Eval EXPR and choose among clauses on that value. [...]
>> | Key values are compared by `eql'.
>> `--------------------------------------------------------
>> that does comparison with `equal' too (or does it exist and I just
>> missed it?).
>
> Not quite what you're asking, but `pcase' uses `equal' to compare strings.
Did not know about that one, thanks. PicoLisp has `casq' as a special
case comparing pointer equalitiy, and `case' that compares with `equal',
so everytime I try to use `case' in Elisp I notice how restricted it
is in comparison.
--
cheers,
Thorsten
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Adding assoc-delete-all / rassoc-delete-all
2014-04-17 12:35 ` Tassilo Horn
2014-04-17 13:15 ` Stefan Monnier
@ 2014-04-17 13:40 ` Thorsten Jolitz
1 sibling, 0 replies; 8+ messages in thread
From: Thorsten Jolitz @ 2014-04-17 13:40 UTC (permalink / raw)
To: emacs-devel
Tassilo Horn <tsdh@gnu.org> writes:
> No, I don't think there is. But I think here a more versatile macro
> would be better than hard-coding another version with the test fixed to
> `equal'.
Indeed, default comparison with `equal' and an '&optional eqlp' argument
would be nice.
--
cheers,
Thorsten
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Adding assoc-delete-all / rassoc-delete-all
2014-04-17 11:39 Adding assoc-delete-all / rassoc-delete-all Tassilo Horn
2014-04-17 11:55 ` Thorsten Jolitz
@ 2014-04-17 15:17 ` Teemu Likonen
1 sibling, 0 replies; 8+ messages in thread
From: Teemu Likonen @ 2014-04-17 15:17 UTC (permalink / raw)
To: Tassilo Horn; +Cc: emacs-devel
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Tassilo Horn [2014-04-17 13:39:41 +02:00] wrote:
> So I'm voting for adding a function `assoc-delete-all' which is just
> like `assq-delete-all' except that it does the comparison with `equal'
> instead of `eq'. Then the above becomes just
That would add symmetry but how about cl-delete(-if(-not))?
(setq Tex-Command-List
(cl-delete "Biber" TeX-command-list
:key 'car :test 'equal))
> For symmetry, I'd also add `rassoc-delete-all' to the existing
> `rassq-delete-all'.
I prefer those generic higher-order Common Lisp versions which already
have all the features.
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^ permalink raw reply [flat|nested] 8+ messages in thread
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-- links below jump to the message on this page --
2014-04-17 11:39 Adding assoc-delete-all / rassoc-delete-all Tassilo Horn
2014-04-17 11:55 ` Thorsten Jolitz
2014-04-17 12:29 ` Stefan Monnier
2014-04-17 13:36 ` Thorsten Jolitz
2014-04-17 12:35 ` Tassilo Horn
2014-04-17 13:15 ` Stefan Monnier
2014-04-17 13:40 ` Thorsten Jolitz
2014-04-17 15:17 ` Teemu Likonen
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