[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: pcase bindings in patterns with complicated logic
From: |
Ihor Radchenko |
Subject: |
Re: pcase bindings in patterns with complicated logic |
Date: |
Sun, 14 Jan 2024 16:21:44 +0000 |
Thierry Volpiatto <thievol@posteo.net> writes:
>>> [ BTW I don't understand why `app` pattern exists as long as now `pred` is
>>> supporting an extra arg ]
>>
>> Isn't it explained right in the manual?
>>
>> ‘(app FUNCTION PATTERN)’
>> Matches if FUNCTION called on EXPVAL returns a value that matches
>> PATTERN. FUNCTION can take one of the forms described for ‘pred’,
>> above. Unlike ‘pred’, however, ‘app’ tests the result against
>> PATTERN, rather than against a boolean truth value.
>
> Perhaps it is right but I don't understand it, an example in the manual
> would be welcome (if there is one I missed it).
Does this example help?
(pcase '(1 2 3)
((app cdr `(2 ,c)) (format "Match: %S" c)))
You cannot easily do the same with pred.
--
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>
- pcase bindings in patterns with complicated logic, Richard Stallman, 2024/01/12
- Re: pcase bindings in patterns with complicated logic, Ihor Radchenko, 2024/01/13
- Re: pcase bindings in patterns with complicated logic, Thierry Volpiatto, 2024/01/14
- Re: pcase bindings in patterns with complicated logic, Thierry Volpiatto, 2024/01/14
- Re: pcase bindings in patterns with complicated logic, Ihor Radchenko, 2024/01/14
- Re: pcase bindings in patterns with complicated logic, Thierry Volpiatto, 2024/01/14
- Re: pcase bindings in patterns with complicated logic,
Ihor Radchenko <=
- Re: pcase bindings in patterns with complicated logic, Thierry Volpiatto, 2024/01/14
- Re: pcase bindings in patterns with complicated logic, Richard Stallman, 2024/01/15
- Re: pcase bindings in patterns with complicated logic, Ihor Radchenko, 2024/01/16
- Re: pcase bindings in patterns with complicated logic, Richard Stallman, 2024/01/17
- Re: pcase bindings in patterns with complicated logic, Ihor Radchenko, 2024/01/18
- Re: pcase bindings in patterns with complicated logic, Richard Stallman, 2024/01/19
- Re: pcase bindings in patterns with complicated logic, Ihor Radchenko, 2024/01/20
- Re: pcase bindings in patterns with complicated logic, Richard Stallman, 2024/01/20
- Re: pcase bindings in patterns with complicated logic, Ihor Radchenko, 2024/01/21
- Re: pcase bindings in patterns with complicated logic, Richard Stallman, 2024/01/23