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<guileHacker4000>Hello, is the author of guile-sdl2 in here?

<chitochi>i think it's dthompson? afk right now i think :/

<guileHacker4000>I understand, thank you. I've sent them a message on mastodon, I hope they'll see it.

<apteryx>does scm_internal_catch return either the result of the body, else the result of the handler, if an exception was handled?, the same as in Scheme?

<euouae>yes, exceptions with 'tag' are caught

<apteryx>what does scm_throw do in C, considering there are no exceptions in C ?

<apteryx>phew, I think I'm done figuring out how to replace select with scm_select in guile-udev

<apteryx>entering debugging phase...

<euouae>apteryx: this one might not be documented very well

<euouae>I don't think it's thread safe? there is a static throw_var that keeps the state

<euouae>no wait, throw_var is the closure called with (key . args).

<euouae>and later it is initialized with scm_c_define("throw", ...)

<euouae>so I'm actually confused about this part, but I figured I'd explain a bit more by looking at the sources.

<apteryx>that's a good suggestion

<apteryx>would someone know how to fix this conversion problem in C: https://paste.debian.net/1301910/

<apteryx>I thought SCM_NEWSMOB was obsoleted by scm_new_smob reading NEWS, but I'm not sure what I'm doing

<euouae>something isn't right there apteryx

<euouae>the guile reference I have says the signature takes a void* as second parameter

<euouae>but your compiler claims it's an scm_t_bits

<euouae>see if the latest version of guile documentation + libguile.h headers makes sense: the signatures should agree (on docs and on the header). If not, it's a bug

<euouae>or wait, the description says: " The initial values data, data2, and data3 are of type scm_t_bits; when you want to use them for SCM values, these values need to be converted to a scm_t_bits first by using SCM_UNPACK. "

<euouae>so I think you need to use return scm_new_smob(udev_hwdb_tag, SCM_UNPACK(uhd));

<apteryx>my reference manual (built from source) does say: C Function: SCM scm_new_smob (scm_t_bits tag, void *data)

<apteryx>the value used as data is a struct, not SCM though

<apteryx>a C struct

<apteryx>here's what it looks like by the way: https://github.com/Apteryks/guile-udev/tree/udev-monitor-improvements

<dsmith>apteryx, Here is an (old) example. The bot has been using this for about 10 years or so: https://gitlab.com/dalepsmith/guile-sqlite/-/blob/master/sqlite.c?ref_type=heads

<apteryx>dsmith: thanks, I'll check it out

<apteryx>ah, you don't use scm_new_smob() ?

<dsmith>apteryx, It's from 10 years ago...

<dsmith>#define SCM_NEWSMOB(z, tc, data) \

<dsmith> z = scm_new_smob ((tc), (scm_t_bits)(data))

<dsmith>Looks like I am..

<apteryx>NEWS suggest it may be deprecated by scm_new_smob in time

<apteryx>ah! is SCM_NEWSMOB defined to do the necessary cast itself?

<apteryx>I guess that NEWS entry is bogus; that macro seems useful

<tomnor>When recurring like the little schemer, (consing a car to a recursion), is there a limit?

<tomnor>I mean, on the number of "loops"

<apoorv569>Hi, I'm new to lisp languages in general. Recently been using guix and learning guile scheme along side.

<apoorv569>I am writing my shell scripts in guile scheme to practice.

<optimal>tomnor: I haven't read the little schemer, but Guile does have tail call elimination, where recursion in the form of tail calls is optimized so it doesn't "blow the stack".

<apoorv569>I'm curious if it possible to have colored output from shell scripts?

<apoorv569>Like from the `(display` procedure for example.

<optimal>tomnor: The Guile manual has a section on Tail Calls: https://www.gnu.org/software/guile/manual/guile.html#Tail-Calls

<tomnor>optimal: yes, thats great

<tomnor>I have just observed that even if a call is not tail recursive, like (cons something (recur something)).

<tomnor>I run that thousands of loop and no crash

<optimal>apoorv569: guile-lib (https://www.nongnu.org/guile-lib) has a `(term ansi-color)' module that can generate the appropriate ANSI color escape sequences for you - https://www.nongnu.org/guile-lib/doc/ref/term.ansi-color/

<optimal>apoorv569: You can install guile-lib with guix via: `guix package -i guile-lib`'

<optimal>tomnor: The expression you describe is tail-recrusive

<tomnor>not to my understanding, the last call is cons

<apoorv569>optimal: I see. Thanks for the recommendation.

<optimal>tomnor: The last call is `recur', no?

<tomnor>Maybe my example is poor, but it is an argument to cons, therefore evaluated before the cons is called

<optimal>I may be wrong, but if the last expression is a call to the current procedure (recursion), I believe that suffices for tail call optimizaiton, but I'm not sure.

<tomnor>One can observe the difference using ,trace

<tomnor>my example build up a "stack"

<tomnor>proper tail recursion does not

<optimal>Then I'm wrong.

<tomnor>optimal: maybe, maybe not. check it out, its very interesting to see the trace like that

<tomnor>I seem inclined now to use name lets everywhere to make proper tail recursion

<tomnor>s/name/named/

<apoorv569>I noticed that I can't seem to `CTRL + C` cancel out of certain commands I run via the guile script.

<apoorv569>Using the `(system` or `(system* procedure.

<Arsen>ah, welcome to the job control jungle

<Arsen>that happens because of some weird interaction between TTYs and programs ran in them that I don't fully grasp

<Arsen>IIRC the TLDP manpage credentials(7) covers this topic

<Arsen>unfortunately, I don't know of good documentation in a good format on this topic

<tomnor>apoorv569: what about ctrl + d ?

<apoorv569>tomor: Can't do ctrl + d either..

<apoorv569>tomnor: ..

IRC channel logs

2023-12-23.log