We can have desestruct one day?

Brainstorming
19

In the ecs I am working on I currently have code like this:

fn drawRectanglesLines(self: *System, archetype: *Archetype) !void {
    const c = try self.input(archetype, struct {
        position: Vec2,
        bounds: Vec2,
        color: ray.Color,
    });

    for (c.position, c.bounds, c.color) |pos, b, color| {
        ray.drawRectangleLines(pos[0] + 1, pos[1] + 1, b[0] - 2, b[1] - 2, color);
    }
}

If there was a special for <tuple> |a, b, c| { ... } I could write this instead:

fn drawRectanglesLines(self: *System, archetype: *Archetype) !void {
    const c = try self.input(archetype, struct {
        position: Vec2,
        bounds: Vec2,
        color: ray.Color,
    });

    for c |pos, b, color| {
        ray.drawRectangleLines(pos[0] + 1, pos[1] + 1, b[0] - 2, b[1] - 2, color);
    }
}

Or even this (if I don’t care about verifying component order/names):

fn drawRectanglesLines(self: *System, archetype: *Archetype) !void {
    for try self.input(archetype, .{Vec2, Vec2, ray.Color}) |pos, b, color| {
        ray.drawRectangleLines(pos[0] + 1, pos[1] + 1, b[0] - 2, b[1] - 2, color);
    }
}

This would work because System has a slice of self.component_ids internally.

Maybe to avoid unreadable expression monstrosities within such a hypothetical tuple-for, it could instead accept a variable name, which would force you to separate that code out:

fn drawRectanglesLines(self: *System, archetype: *Archetype) !void {
    const components = try self.input(archetype, .{Vec2, Vec2, ray.Color}); // returns tuple
    for components |pos, b, color| {
        ray.drawRectangleLines(pos[0] + 1, pos[1] + 1, b[0] - 2, b[1] - 2, color);
    }
}

I would like that tuple-for possibility, but what I suggest would be a new kind of syntax we haven’t had so far (dropping the parentheses from a syntactic form), but I like it because it seems very readable.

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