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bug#31715: cl-incf and cl-decf error out when passed a nil-valued variab
From: |
Clément Pit-Claudel |
Subject: |
bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset' |
Date: |
Tue, 5 Jun 2018 19:01:56 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 |
On 2018-06-05 18:53, Noam Postavsky wrote:
> Both SBCL and CLisp throw an error for (let ((x 1) (y nil)) (incf x y)),
> although I can't see anything in the Common Lisp spec to decide either
> way. E.g., cltl2 says:
>
> If delta is not supplied, then the number in place is changed by 1.
>
> https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node125.html
Thanks for looking up the spec and testing other implementations. I'm not sure
what to make of the result with SBCL and CLisp, since (incf x nil) also fails
in both of them (whereas it works for us, since we can't distinguish nil and
unspecified).
>> In the rest of Emacs there are lots of other examples. Many of them
>> (for example semantic-find-tags-by-name or calendar-increment-month)
>> seem to work when passed a nil-valued variable, but many others behave
>> like cl-incf (for example gnus-summary-article-score).
>
> I don't think those are great examples of macros to emulate.
Agreed, I was just collecting other examples, both in support and against my
point.
Clément.
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- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Clément Pit-Claudel, 2018/06/04
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Noam Postavsky, 2018/06/04
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Michael Heerdegen, 2018/06/04
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Noam Postavsky, 2018/06/04
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Michael Heerdegen, 2018/06/04
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Clément Pit-Claudel, 2018/06/05
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Noam Postavsky, 2018/06/05
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset',
Clément Pit-Claudel <=
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Noam Postavsky, 2018/06/05
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Clément Pit-Claudel, 2018/06/05
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Michael Heerdegen, 2018/06/05
- bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Noam Postavsky, 2018/06/05
bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset', Clément Pit-Claudel, 2018/06/05