state variable constrained accepts

const std = @import("std");
const Data = struct { value: i32 };

~pub tor alloc {} -> *Data<owned>

~proc alloc|zig {
    const allocator = std.heap.page_allocator;
    const d = allocator.create(Data) catch unreachable;
    d.* = Data{ .value = 42 };
    return d;
}

~pub tor borrow { other: *Data<owned> } -> *Data<borrowed>

~proc borrow|zig {
    return other;
}

// Generic processor constrained to owned OR borrowed
// Will NOT accept other states like "gc" or "static"
~pub tor process { d: *Data<M'owned|borrowed> } -> *Data<M'owned|borrowed>  // Preserves whichever state was passed

~proc process|zig {
    return d;
}

// Generic processor constrained to owned OR borrowed
// Will NOT accept other states like "gc" or "static"

~pub tor process { data: *Data<M'owned|borrowed> } -> *Data<M'owned|borrowed>  // Preserves whichever state was passed

~proc process|zig {
    return data;
}