// Error-set declarations + `error.X` tag values + enum-like `==` typing
// (ERR step E1.1). A declared `error { ... }` set is a real type with a u32
// runtime layout; `error.X` is its tag value — the named set when context
// provides one (membership-checked), else the raw global u32 id. Tags compare
// with an `error.X` literal or another error-set value. The rejections live in
// `examples/218-error-set-typing.sx`.

#import "modules/std.sx";

ParseErr :: error { BadDigit, Overflow, Empty }

main :: () -> s32 {
    c : ParseErr = error.BadDigit;
    d : ParseErr = error.Overflow;
    r : s32 = 0;
    if c == error.BadDigit { r = r + 1; }    // true  -> +1
    if c == error.Overflow { r = r + 2; }     // false
    if c == d              { r = r + 4; }     // false (BadDigit != Overflow)
    if d == error.Overflow { r = r + 8; }     // true  -> +8
    tag : u32 = error.Empty;                  // u32 context -> raw global tag id
    if tag != 0 { r = r + 16; }               // tag ids are >= 1 -> +16
    print("error-set result: {}\n", r);       // -> 25
    return r;
}