v-uing binding issues

[trufae]

Describe the bug

I'm writing the bindings for the UI-ng library, which is a thin wrapper around mac, windows and gtk graphical widget APIs. It can compile statically and I think it could be a great base for writing native looking apps for those platforms in V.

The problem I'm facing is that the API takes uiControl types as a generic cast (union like) for all the type of widgets, no matter if they are boxes, labels or buttons. So to make this typable in the V side I use an union type using this:

type Control = C.uiButton | C.uiLabel | C.uiBox | Button | Label | Box

Which results in a problem because V uses a HEAP cast when tranalsting this to C instead of just passing the pointer with a bare cast. To keep the V usage as simple as possible I didn't wanted to create a full abstraction of all this, and i think it will be doable if V could express that kind of uses somehow without an unboxing.

Reproduction Steps

The commit ec0951ac4405aaf7152c491ad925accfec5f625b shows the problem because i managed to get it to work by using unsafe voidptr

Expected Behavior

make the api typable iinstead of depending on voidptr

Current Behavior

segfault if i use typed variables

Possible Solution

i'm not as good as i would about the V internals to understand which should be the right behaviour on using an union type with multiple C types which end up 1:1 mapped with V. So i'm filling a ticket here as requested in the Discord to find a better solution before continue working on finishing the bindings.

Additional Information/Context

to install libuing i used r2pm -ci libuing

V version

V 0.4.8 70112d8

Environment details (OS name and version, etc.)

0$ v doctor
V full version: V 0.4.8 584cedd.70112d8
OS: macos, macOS, 15.1, 24B83
Processor: 10 cpus, 64bit, little endian, Apple M1 Max

getwd: /Users/pancake/prg/v-uing
vexe: /Users/pancake/prg/v/v
vexe mtime: 2024-11-13 07:54:10

vroot: OK, value: /Users/pancake/prg/v
VMODULES: OK, value: /Users/pancake/.vmodules
VTMP: OK, value: /tmp/v_501

Git version: git version 2.39.5 (Apple Git-154)
Git vroot status: weekly.2024.13-1383-g70112d84 (41 commit(s) behind V master)
.git/config present: true

CC version: Apple clang version 16.0.0 (clang-1600.0.26.3)
emcc version: N/A
thirdparty/tcc status: thirdparty-macos-arm64 713692d4

_{Huly®: V_0.6-21329}

Note

You can use the 👍 reaction to increase the issue's priority for developers.

Please note that only the 👍 reaction to the issue itself counts as a vote.
Other reactions and those to comments will not be taken into account.