09:54 <Serpent7776> why are backtraces not enabled by default when I run script with ocaml?

09:55 <zozozo> Serpent7776: backtrace have a very slight performance penalty so they aren't enabled by default (and theyr equire the executable to be compiled with -g iirc), to enable them, you can use OCAMLRUNPARAM=b, et call Printexc.record_backtrace from within your script

09:55 <zozozo> *or call

09:58 <Serpent7776> yeah, I enabled OCAMLRUNPARAM=b, but still don't have location information in my sources. There's no way to get backtrace with ocaml command? I need to compile to native code?

09:59 <zozozo> Serpent7776: when I try OCAMLRUNPARAM=b ocaml my_script.ml, I get backtraces, what is your setup exactly ?

10:01 <zozozo> ah, well actually, it seems that the location within the scripts are indeed not provided (or rather printed as "unknown location", :/

10:02 <Serpent7776> yeah, I only get locations from stdlib functions

10:04 <zozozo> hm... so I don't know how to enable debug infos in scripts, maybe ask on the forum ?

10:06 <Serpent7776> ok, thank you

10:10 <Armael> that's weird, because it does work in the toplevel

10:11 <zozozo> yeah, it might just be a matter of adding the option to ocaml

10:56 <mbuf> !hello

10:56 <ocabot> hello mbuf

10:57 <Serpent7776> asked here https://discuss.ocaml.org/t/backtraces-in-script-run-by-ocaml/5970

11:07 <Armael> that looks like a bug in the toplevel tbh; I've tried investigating a bit but I'm not too familiar with this part of the code

11:11 <Armael> but it looks like the same issue appears even in the toplevel directly?

11:11 <Armael> without passing the script on the commandline

11:12 <Armael> but executing its contents manually in the toplevel

11:18 <Serpent7776> hmm, when I `#use test.ml` in toplevel it suddenly works

11:19 <Serpent7776> but this doesn't work it utop for some reason

11:25 <Armael> really? I tried with use and that didn't work for me either

11:25 <Armael> which version of ocaml are you using

11:26 <Armael> (that, and what happens with #use and/or utop is worth mentionning in the forum post I think)

11:28 <Serpent7776> I'm using ocaml-base-compiler.4.10.0 from opam in local switch

11:31 <Serpent7776> also #use works for my actual ~100 lines script, but not for script I posted

11:32 <Armael> ah

11:32 <Armael> it might also be that the functions are getting inlined, I'm not sure

14:29 <HyperTables> say I have a 17-bit value in an int (that is, it will be in the range [0, 0x7FFFF]) how do I sign-extend it to 32 bits in OCaml? (this will be running in a 64-bit environment where there are enough bits to do calculations on all 32-bit values)?

14:30 <HyperTables> actually modify that, I need to sign extend it to the full range of int so that I can use the signed value in arithmetic

14:31 <HyperTables> in C i would just left shift by the number of missing bits and arithmetic right shift back down the same amount

14:31 <HyperTables> but in OCaml I don't know how many bits that is; it's implementation-dependent

14:32 <Anarchos> HyperTables lsl, asr ?

14:34 <Anarchos> oh sorry i missed you don't know how many bits. maye you can Do Unix.excve a "sysinfo" command to get the underlying architecture ?

14:57 <flux1> HyperTables: `Sys.int_size` tells you the int size

15:27 <HyperTables> hm ok that seems to work for my use case, thanks flux1

19:37 <flux1> I don't enjoy the way ppx deriving yojson handles sum types. I guess there's no better solution than to either write the mappings manually or write some generic function to convert the generated functions?

19:37 <flux1> it would be much more json-y if they were like object first, then arguments would be in array

19:37 <flux1> hmm, in fact I wonder if it supports inline records..