Cannot use $if/$else to set value of enum.

[islonely]

V doctor:

V full version: V 0.4.9 4225a34.42222e6
OS: macos, macOS, 15.1.1, 24B91
Processor: 8 cpus, 64bit, little endian, Apple M3

getwd: /Users/adamoates/.vmodules/islonely/mouse
vexe: /Users/adamoates/v/v
vexe mtime: 2025-01-01 19:24:10

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

Git version: git version 2.39.5 (Apple Git-154)
Git vroot status: weekly.2024.53-6-g42222e6c
.git/config present: true

CC version: Apple clang version 16.0.0 (clang-1600.0.26.4)
emcc version: N/A
thirdparty/tcc status: thirdparty-macos-arm64 713692d4

What did you do?
./v -g -o vdbg cmd/v && ./vdbg /Users/adamoates/Documents/test.v

enum Foo {
	foo = $if macos { 1 } $else { 0 }
}
fn main() {}

What did you expect to see?

Expecte enum Foo.foo value to be 1 on MacOS and 0 on other systems.

What did you see instead?

/Users/adamoates/Documents/test.v:2:8: error: the default value for an enum has to be an integer
    1 | enum Foo {
    2 |     foo = $if macos { 1 } $else { 0 }
      |           ~~~
    3 | }
    4 | fn main() {}

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_{Huly®: V_0.6-21767}

[Delta456]

enum Foo {
	foo = if macos { 1 } else { 0 }
}
fn main() {}

The above code gives an error so ternary conditions is not supported entirely for enum fields

[jorgeluismireles]

Imho I'll be happy using a method:

enum Foo {
	foo
}

fn (f Foo) val() int {
	match f {
		.foo {
			return $if macos { 1 } $else { 0 }
		}
	}
}

fn main() {
	println('${Foo.foo.val()}') // prints 0
}

[jorgeluismireles]

Another workaround

const x = $if macos { 1 } $else { 2 }

enum Foo {
	foo = x
}

fn main() {
	println('${Foo.foo:d}') // prints 2
}

[jorgeluismireles]

But then, a bug kicks in, next program causes two enum members have the same value:

const x = $if macos { 1 } $else { 2 }
const y = $if macos { 3 } $else { 2 }

enum Foo {
	foo = x
	bar = y
}

fn main() {
	println('${Foo.foo:d}') // prints 2
	println('${Foo.bar:d}') // prints 2
}

A problem which is catch when we type directly a repeated value:

code.v:6:7: error: enum value `2` already exists
    4 | enum Foo {
    5 |     foo = 2
    6 |     bar = 2
      |          ^
    7 | }
    8 |
}

[medvednikov]

Great find!