IRC channel logs

<cow_2001>(cond ((library (srfi 0)) 'a)) => error! instead of the symbol a

<cow_2001>what is going on?

<cow_2001>err

<cow_2001>cond-expand, sorry

<cow_2001>does guile support the (cond-expand ((library (some library path)) 'a)) where (some library path) is a library you can import and the whole cond-expand value would be a 'a

<cow_2001>?

<cow_2001>trying to make srfi-123 work where it is used

<cow_2001>i have a fix to an example in the manual for srfi-31, but i cannot currently post a git format-patch file. it is here: https://codeberg.org/kakafarm/guile/src/branch/fix-srfi-31-example

<cow_2001>the diff: https://codeberg.org/kakafarm/guile/compare/master...fix-srfi-31-example

<cow_2001>oh, and hash: a9cb6dd0156ebbd9ff2448dba05207e885b57608

<cow_2001>i have a feeling i could have just written a compressed base64 message of the format-patch file and it would have been shorter than the above few messages

<cow_2001>also working on https://codeberg.org/kakafarm/guile-srfi-123

<cow_2001>maybe will write a package definition for guix tomorrow

<dariqq>hi, are there examples somewhere for how to catch exceptions with libguile?

<dariqq>i think i figured it out

<rlb>dariqq: presume you found it, but in case not: https://www.gnu.org/software/guile/manual/html_node/Exceptions.html

<dariqq>rlb: thanks, I had some problems how to use scm_c_catch especially how to handle things when the function takes more than one argument but found some examples through searching which helped

<rlb>Ahh, ok.

<dsmith>dariqq, It's kind of complicated, but here is an example of handling Scheme -> C -> Scheme -> raise https://gitlab.com/dalepsmith/guile-sqlite/-/blob/master/sqlite.c?ref_type=heads#L141

<dsmith>(That's the code the bot has been using for about the last 20 years or so)

<sneek>ACTION waves

<dsmith>sneek, version

<sneek>Sneeky bot running on Guile version 3.0.3 using bobot++ release.2.3.1-6-a463-dirty

<dariqq>dsmith: Thanks, currently i am just doing the equivalent of false-if-exception for things like scm_call_x which is a lot more involved than I thought. I guess the macro hides a lot of the complexity away when not using C

<lechner>Hi, can this 'car' on top of 'assq-ref' be written more concisely? (let* ((maybe (assq-ref alist key))) (if maybe (car maybe) #f))

<dthompson>(and=> (assq-ref alist key) car)

<dthompson>I think... not tested :)

<lechner>dthompson / thanks, it works!

<dthompson>yay sometimes the ol' brain gets it right on the first try

<mwette>and=> is one of the gems

<dsmith>yey!

<Arsen>oh wow, that's neat

<lechner>Hi, does anyone have an example for a macro that takes an ellipsis of lists, i.e something like (manufacturer . name) ... to be used with something like (gold-delicious "Golden Delicious Apple") (banana "Cavendish banana") I'm not sure how to access the key and datum separately

<dsmith>"(manuf name) ..." and then "manuf ..." and "name ..."

<lechner>wow, that works?

<dsmith>Probably not what you meant/wanted.

<lechner>can I also use "(manuf name) ..." in one place?

<lechner>in the template

<dsmith>If in your template you can have zero or more of that, yeah

<dsmith>The classic case is a let with `(binding value) ...` transformed into a lambda with the `(binding ...)` and applying it to the `value ...`

<lechner>dsmith / wow, that just solved one of my big feature ideas!

<lechner>dsmith / thank you so much!

<dsmith>Sure! np

<mwette>more examples: https://www.scheme.com/tspl4/syntax.html#./syntax:h4

<dsmith>mwette, Hah! I was just looking for that!