Re: Template + alias + basic type depends on another parameter = broken?
On Wednesday, 22 February 2023 at 20:20:46 UTC, Dark Hole wrote:
```d
template Foo(T, alias T[] Array) {
// ...
}
// ...
Bar[] arr;
Foo!(Bar, arr);
```
This is valid D, but it doesn't work. It gives error "Error:
template instance `Foo!(Bar, arr)` does not match template
declaration `Foo(T, alias T[] Array)`".
Of course, there is some ways to avoid this error (e.g. check
Array type in if), but I don't undestand why this code doesn't
compiles.
Pretty sure this is just a bug. There are a lot of edge-case bugs
like this where template instantiation doesn't work the way it's
supposed to.
I've submitted a bug report for this on issues.dlang.org:
https://issues.dlang.org/show_bug.cgi?id=23733
Template + alias + basic type depends on another parameter = broken?
I'm trying to rewrite really old D code. There was fragment like
that:
```d
template Foo(T, T[] Array) {
// ...
}
// ...
Bar[] arr;
Foo!(Bar, arr);
```
This gives error `can't read arr in compile time`. Small changes:
```d
template Foo(T, alias T[] Array) {
// ...
}
// ...
Bar[] arr;
Foo!(Bar, arr);
```
This is valid D, but it doesn't work. It gives error "Error:
template instance `Foo!(Bar, arr)` does not match template
declaration `Foo(T, alias T[] Array)`".
Of course, there is some ways to avoid this error (e.g. check
Array type in if), but I don't undestand why this code doesn't
compiles.
Re: importC - how to use more effectively?
On Wednesday, 22 February 2023 at 15:00:56 UTC, WebFreak001 wrote: I just first time used importC in a prototype project I just worked on. I used it to just import `libevdev.h` on linux to register a custom input device / make a simple userspace input driver. A suggestion: try tcc as preprocessor. It works better than gcc for importc. Andrea Fontana
importC - how to use more effectively?
I just first time used importC in a prototype project I just worked on. I used it to just import `libevdev.h` on linux to register a custom input device / make a simple userspace input driver. Now libevdev comes with two header files: libevdev.h and libevdev-uinput.h Q1) Since libevdev-uinput.h included libevdev.h, I could simply import that to get everything. What would I do in more complex libraries that are composed of multiple header files though? I had a small problem: linux/input.h was included, but not found / not properly processed, so I had to manually look that up in the correct architecture folder of my linux distro. What I now did was copy-pasting the files both from libevdev and from linux/input.h from my local system into my project directory, running `gcc -E` and manually cleaning up things, so that stuff like `u8` existed. (using a package in D that I would `__import` to include compat things) Q2) How would I do this without manually copying and editing the header files, so that it would work on other people's machines as well, using their local headers? --- I'm quite a fan of how easy it was using importC to get libevdev running in my custom program and quickly making a basic custom input device, exactly with the same syntax and functions as in C, but this only really seems to work inside the prototyping phase. What would be the next steps if I wanted to make e.g. a libevdev wrapper to put on DUB? Q3) Would generating D code from importC be possible for this?
Re: How to get only the field name from an alias?
On Tuesday, 21 February 2023 at 12:32:51 UTC, Adam D Ruppe wrote: On Tuesday, 21 February 2023 at 02:41:34 UTC, Elfstone wrote: apparently F.stringof You almost never want to use .stringof, instead try __traits(identifier, F) and see what it gives you. Alternatively, loop over __traits(allMembers) which gives you the member names and pass that down. You can pull all the info out of allMembers with getMember and then other things to filter it out. Thanks, Adam! Didn't know such a trait existed and that it could work for aliases.
