Add bsd environment specific file support

[kimshrier]

Describe the feature

We have a _nix.c.v environment specific file name for any os that is not Windows. This seems overly general to me, but that is not something I want to address just yet.

I would like to add a _bsd.c.v name which would be compiled if one was on macos, freebsd, openbsd, netbsd, or dragonfly.

I would also like to propose an order of selection such that the most specific environment specific file is chosen. For example, assume that I am on freebsd and I have the following files in my project:

my_v_project/
    main.v
    something_default.c.v
    something_windows.c.v

I would expect main.v and something_default.c.v would be compiled since freebsd is not windows.

If I added something_nix.c.v to this directory, I would expect main.v and something_nix.c.v to be compiled since freebsd is a kind of unix.

If I then added something_bsd.c.v to this directory, I would expect main.v and something_bsd.c.v to be compiled. Since _bsd.c.v is more specific than _nix.c.v it gets chosen instead of _nix.c.v or _default.c.v.

If I added something_freebsd.c.v so that my directory now looks like this:

my_v_project/
    main.v
    something_bsd.c.v
    something_default.c.v
    something_freebsd.c.v
    something_nix.c.v
    something_windows.c.v

I would expect main.v and something_freebsd.c.v to be compiled since I have an environment specific file name that exactly matches the os.

Use Case

In vlib/fasthttp there are the following environment specific files:

fasthttp_darwin.v
fasthttp_linux.v
fasthttp_windows.v

I have copied fasthttp_darwin.v to fasthttp_freebsd.v and it works with no changes. I suspect that the same would be true for openbsd, netbsd, and dragonfly. Although I don't have openbsd, netbsd, and dragonfly systems I can test on locally.

The brute-force solution would be to create fasthttp_openbsd.v, fasthttp_netbsd.v and fasthttp_dragonfly.v files but having 5 identical copies of a file is a maintenance problem (and it smells bad).

Having a generic bsd os environment specific file would mean that we could just rename fasthttp_darwin.v to fasthttp_bsd.v and the single file would work on all 5 variants of bsd.

Proposed Solution

I propose adding a bsd os value and adopting the order of selection as described above.

I may need some assistance if I implement this.

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

Version used

V 0.5.1 d261348

Environment details (OS name and version, etc.)

$ v doctor
|V full version      |V 0.5.1 d261348cb906ecb34daa7d87d3a967416e2db192
|:-------------------|:-------------------
|OS                  |freebsd, 15.0-RELEASE-p3, FreeBSD 15.0-RELEASE-p3 releng/15.0-n281008-5cf7232732d5 GENERIC
|Processor           |2 cpus, 64bit, little endian
|Memory              |0.66GB/3.97GB
|                    |
|V executable        |/home/kim/Projects/v/from_github/v/v
|V last modified time|2026-03-21 19:31:37
|                    |
|V home dir          |OK, value: /home/kim/Projects/v/from_github/v
|VMODULES            |OK, value: /home/kim/.vmodules
|VTMP                |OK, value: /tmp/v_1002
|Current working dir |OK, value: /home/kim/Projects/v/from_github/v
|                    |
|env VFLAGS          |"-cc clang"
|Git version         |git version 2.53.0
|V git status        |0.5.1-193-gd261348c
|.git/config present |true
|                    |
|cc version          |FreeBSD clang version 19.1.7 (https://github.com/llvm/llvm-project.git llvmorg-19.1.7-0-gcd708029e0b2)
|gcc version         |N/A
|clang version       |FreeBSD clang version 19.1.7 (https://github.com/llvm/llvm-project.git llvmorg-19.1.7-0-gcd708029e0b2)
|tcc version         |tcc version 0.9.28rc 2025-02-13 HEAD@f8bd136d (x86_64 FreeBSD)
|tcc git status      |thirdparty-freebsd-amd64 204a2d97
|emcc version        |N/A
|glibc version       |N/A

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[JalonSolov]

What you are describing, as far as specificity of files compiled, is the way V is supposed to work already. If it's not working that way now, please supply an example which shows the problem.

I agree that it seems like a good idea to support _bsd as a specifier, for the bits that are common across all "flavors" of BSD.

Personally, I would prefer (in your last case) that all of something.v, something_bsd.v and something_freebsd.v be processed - then there wouldn't be any need to duplicate anything, only override those that needed to be different... and there wouldn't be any need for _default files. Then something_freebsd.v would ONLY have freebsd specific things in it.

[kimshrier]

I can demonstrate the problem using a variation of the code in the documentation section Conditional compilation / Environment specific files.

I'll create a new V project on a FreeBSD system and edit main.v to match the example from the documentation.

$ v version
V 0.5.1 d261348

$ v new broken_env_spec
Input your project description: demonstrate broken environment specific files
Input your project version: (0.0.0) 
Input your project license: (MIT) 
Initialising ...
Created binary (application) project `broken_env_spec`

$ cd broken_env_spec
$ ls -l
total 8
-rw-r--r--  1 kim kim  45 Mar 22 12:39 main.v
-rw-r--r--  1 kim kim 150 Mar 22 12:37 v.mod

$ cat main.v
module main

fn main() {
        println(message)
}

I expect the following to fail because message has not been defined yet.

$ v run .
main.v:4:10: error: undefined ident: `message`
    2 | 
    3 | fn main() {
    4 |     println(message)
      |             ~~~~~~~
    5 | }
main.v:4:2: error: `println` can not print void expressions
    2 | 
    3 | fn main() {
    4 |     println(message)
      |     ~~~~~~~~~~~~~~~~
    5 | }

Create the main_default.v file. The v run . command should now work.

$ ls -l
total 12
-rw-r--r--  1 kim kim  43 Mar 22 12:39 main_default.v
-rw-r--r--  1 kim kim  45 Mar 22 12:39 main.v
-rw-r--r--  1 kim kim 150 Mar 22 12:37 v.mod

$ cat main_default.v
module main

const message = 'Hello world'

$ v run .
Hello world

$

Create the main_freebsd.v file. The v run . command should still work and show the freebsd message. However, it produces the following error:

$ ls -l
total 16
-rw-r--r--  1 kim kim  43 Mar 22 12:39 main_default.v
-rw-r--r--  1 kim kim  45 Mar 22 12:59 main_freebsd.v
-rw-r--r--  1 kim kim  45 Mar 22 12:39 main.v
-rw-r--r--  1 kim kim 150 Mar 22 12:37 v.mod

$ cat main_freebsd.v
module main

const message = 'Hello freebsd'

$ v run .
main_freebsd.v:3:7: error: duplicate const `message`
    1 | module main
    2 | 
    3 | const message = 'Hello freebsd'
      |       ~~~~~~~

If I remove the main_default.v file, things work.

$ ls -l
total 12
-rw-r--r--  1 kim kim  45 Mar 22 12:59 main_freebsd.v
-rw-r--r--  1 kim kim  45 Mar 22 12:39 main.v
-rw-r--r--  1 kim kim 150 Mar 22 12:37 v.mod

$ v run .
Hello freebsd

$

I also tried creating a main_nix.v file instead of a main_freebsd.v file and got the following results:

$ ls -l
total 16
-rw-r--r--  1 kim kim  43 Mar 22 12:39 main_default.v
-rw-r--r--  1 kim kim  41 Mar 22 12:40 main_nix.v
-rw-r--r--  1 kim kim  45 Mar 22 12:39 main.v
-rw-r--r--  1 kim kim 150 Mar 22 12:37 v.mod

$ cat main_nix.v
module main

const message = 'Hello nix'

$ v run .
main_nix.v:3:7: error: duplicate const `message`
    1 | module main
    2 | 
    3 | const message = 'Hello nix'
      |       ~~~~~~~

And just to see what having both a nix and a freebsd file would do.

$ ls -l
total 20
-rw-r--r--  1 kim kim  43 Mar 22 12:39 main_default.v
-rw-r--r--  1 kim kim  45 Mar 22 12:59 main_freebsd.v
-rw-r--r--  1 kim kim  41 Mar 22 12:40 main_nix.v
-rw-r--r--  1 kim kim  45 Mar 22 12:39 main.v
-rw-r--r--  1 kim kim 150 Mar 22 12:37 v.mod

$ v run .
main_freebsd.v:3:7: error: duplicate const `message`
    1 | module main
    2 | 
    3 | const message = 'Hello freebsd'
      |       ~~~~~~~
main_nix.v:3:7: error: duplicate const `message`
    1 | module main
    2 | 
    3 | const message = 'Hello nix'
      |       ~~~~~~~

I also tried just having the nix and freebsd files without the default file.

$ ls -l
total 16
-rw-r--r--  1 kim kim  45 Mar 22 12:59 main_freebsd.v
-rw-r--r--  1 kim kim  41 Mar 22 12:40 main_nix.v
-rw-r--r--  1 kim kim  45 Mar 22 12:39 main.v
-rw-r--r--  1 kim kim 150 Mar 22 12:37 v.mod

$ v run .
main_nix.v:3:7: error: duplicate const `message`
    1 | module main
    2 | 
    3 | const message = 'Hello nix'
      |       ~~~~~~~

This seems to show behavior that doesn't match the documentation.

[kimshrier]

I like the idea of processing all the environment specific files as you suggested and not needing to duplicate anything. The more specific files would override the less specific files and we can do away with the _default file.

I was thinking of suggesting that (or something like that) myself but I knew that I didn't have enough familiarity with the compiler internals to pull that off without a lot of assistance. Also, I didn't want to overburden this feature request with too many changes.

I figured that I (or we) could get the bsd variant working. Then look at layering the environment specific files to handle overrides and do away with _default.