How to assign (already-declared) variables in a @match

[rben01]

I have a match that looks like this:

markup::define! {
	Test() {
		@let x = Some(1);
		@let y;
		@match x {
			Some(n) => { y = n },
			None => { y = -1 },
		}
	}
}

The error I get is

error: expected one of: `;`, curly braces, string literal
   --> src/lib.rs:127:19
    |
127 |             Some(n) => { y = n },
    |                            ^

The easiest fix is to simply write @let _ = match { ... }, as this “reenables” some Rust syntax that is seemingly not allowed within @match. But then this leads to a clippy warning, which I can't figure out how to silence because #[allow(clippy::let_unit_value)] isn't allowed in define!. (I could silence the warning at a coarser scope, but don't want to.)

I've tried various things, mostly mucking around with moving an @ sign here and there, and removing the let (so just _ = match { ... } and @_ = match { ... }, at least one of which feels like it should be legal, but no such luck). I can't figure out how to just assign a variable as a statement inside a @match. Various other solutions lead to the trait bound (): markup::Render is not satisfied (i.e., an assignment itself cannot be rendered — fair enough).

Does markup support a way to accomplish this (maybe y @= n?), or to more generally include arbitrary rust code in define!? I'd also reached for ${ ... } as a way to say “the stuff in the {} is to be run but not rendered” but that didn't work either.

Edit: I've wrapped the whole match in a @fn, which gives me access to all the Rust syntax I need, but this seems like overkill.

[fanelfaa]

if you just want to set the @let y variable you can do like this:

markup::define! {
    Test() {
		@let x = Some(1);
		@let y = match x {
			Some(n) => n,
			None => -1,
		};
                @y
	}
}

[rben01]

Thanks, but my issue is that I'd like to assign multiple variables. My plan is to pre declare the variables and then assign in the match. If I used a @let, I'd need to use a tuple to do the assignment, which gets unwieldy (especially when the assignment logic is determined at different levels of nested matches).

[Kijewski]

I'd propose to simply remove @let variable; patterns. You can always refactor your match statements to return a tuple, so that all variables are assigned afterwards.

[rben01]

My issue is that I would like to replicate the following:

let x = Some(1_u32);
let y;
let z;

match x {
    Some(n) => {
        y = "some";
        z = match n {
            0 => "zero",
            1..=5 => "small",
            6..=10 => "medium",
            11.. => "big"
        };
    }
    None => {
        y = "none";
        z = "n/a"
    }
}

Were I to convert to using tuples, I would have to include "some" in every branch of z's match in the Some(n) branch, which is a bit annoying (and unnecessary in standard Rust).