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<apteryx>how would I generate a backtrace programatically upon encountering a fatal crash (I want to log it?)
<wingo>apteryx: see implementation of call-with-error-handling
<wingo>there is also the backtrace procedure
<wingo>starting to think we should merge fibers into guile :P
<wingo>also we should make a release
<apteryx>wingo: thanks!
<apteryx>wingo: thanks! a new release would be nice! I have a bunch of NEWS items to make it more featureful if needed ;-) (new SRFIs and some R7RS fixes)
<apteryx>wingo: is the 'backtrace' documented somewhere, or where is it defined?
<apteryx>ah, SCM_DEFINE (scm_backtrace_with_highlights, "backtrace", 0, 1, 0, ... in backtrace.c ?
<mwette>apteryx: there is something in system/repl/error-handling.scm, search for print-frames
<cobra>dthompson: I see you're the maintainer of guile-sdl2. How does one create a surface with a background color?
<cobra>Specifically, I want to make the surface transparent
<dthompson>cobra: I think you want fill-rect
<dthompson>I don't use surfaces, myself. I use opengl.
<cobra>The surface automatically has a black background though, so trying to use fill-rect with a transparent color will just overlay it on top of the black
<cobra>I guess I will look into using opengl
<apteryx>can I get the continuation from an exception to pass it to make-stack?
<apteryx>I don't want to get the extra frames from my handler
<apteryx>maybe, (call/cc get-backtrace) within my handler?
<apteryx>with get-backtrace accepting a continuation object
<apteryx>that seems to work yes
<dthompson>cobra: have you tried it?
<apteryx>hm, not sure actually
<dthompson>you absolutely do not need to use opengl to have a clear background
<dthompson>the docs say that there is no blending
<dthompson>it literally overwrites the color information with what you specify
<dthompson>no alpha blending applied
<apteryx>I'm getting "unknown file" instead of my program file name when using (backtrace):
<apteryx>any ideas?
<apteryx>here's the demo program used:
<apteryx>basically what I'd wish for is something like we have in Python: logging.exception("message"), with the current exception info (backtrace) added below the message.
<cobra>dthompson: filling the surface with (fill-rect surf (make-rect 0 0 x y) color) where color is #xffffff7f and the surface format is 'rgba8888 results in this:
<cobra>the same after replacing make-rect with #nil
<cobra>am i doing something wrong?
<cobra>where the surface isn't, the window is completely transparent
<dthompson>cobra: #x7f is 127 which brings the full white down to a mid gray. looks correct to me.
<dthompson>are you expecting to see through the entire window?
<dthompson>that wouldn't be possible with what you're trying to do
<cobra>i see
<dthompson>I thought you just wanted transparent color data in the surface, which you have achieved
<dthompson>how are you blending when you blit the surface?
<dthompson>perhaps if you blit with no blending at all then you will get the look you're after
<dthompson>I haven't tried this
<cobra>I'm currently converting the surface to a texture with surface->texture, and using set-texture-blend-mode! setting it to none makes it not transparent at all
<dthompson>yeah sounds like it's either not possible to do what you want with sdl or you need to lookup what the proper technique is
<dthompson>all I can tell you is that your surface pixels are correct according to the code you've shown
<cobra>i see
<cobra>i'll look more into it
<apteryx>what's the smallest amount of resident memory guile daemon typically uses?
<apteryx>mine takes 12.9 MiB
<apteryx>random fact: the Guile 3.0.9 VM uses 1 MiB extra of resident compared to Python 3.10.7 (tested using a while loop on Guix)
<apteryx>shared memory is nice; having Shepherd run with on Guile in Guix System means other Guile processes reuse that same memory for their main VM
<apteryx>reading info '(guile) Smobs', there's this mention: "“applicable SMOBs” that's supposed to be discussed, but I don't see where?
<civodul>apteryx: an “applicable SMOB” can be applied like a regular procedure
<civodul>SMOBs are sorta deprecated though
<civodul>not formally deprecated, but “foreign objects” are the newer API for this
<dthompson>and you can define new applicable data types without using C at all
<apteryx>I was looking at the source of, which uses smobs
<apteryx>it's 3 years old
<apteryx>dthompson: interesting
<dthompson>for example:
<dthompson>we use applicable structs in hoot for running wasm scheme inside guile scheme somewhat transparently :)
<dthompson>a wasm scheme procedure that's plucked out of the wasm runtime can be called as if it were any old procedure
<apteryx>hm. I'll need to ponder over all of this some to get a clue :-)
<dthompson>there's just no nice high level api for it. gotta use the not-so-pleasant low level struct api
<apteryx>can we define keyword arguments procedure from C? The closest I know to do is SCM_DEFINE with optional args
<apteryx>define scheme procedures using keyword arguments*
<civodul>it’s possible, but not so nice
<apteryx>parsing the rest argument perhaps[/
<civodul>in general, people tend to prefer (system foreign) over the C interface
<civodul>there’s ‘scm_c_bind_keyword_arguments’
<civodul>via the rest arguments, yes
<civodul>(i think i’ve never used it :-))
<apteryx>good to know about scm_c_bind_keyword_arguments!
<apteryx>I think I'll stick to positional arguments and having two of them accept false values, for a very similar result