authorgravatar for quae@daurnimator.comdaurnimator <quae@daurnimator.com> 2020-12-13 22:03:59+11:00
committergravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2021-01-01 15:48:04-07:00
log73bf2e1525a392d367525ef96196fe15b14d8c30
tree3191dcafffdad28e49092c156aa734e157c26945
parentc5ec096b2ffd42aff6385debe2a412a6db67868f

std: add std.meta.FieldEnum

1 files changed, 37 insertions(+), 0 deletions(-)

lib/std/meta.zig+37
......@@ -568,6 +568,43 @@ test "std.meta.fieldNames" {
568568 testing.expectEqualSlices(u8, u1names[1], "b");
569569}
570570
571pub fn FieldEnum(comptime T: type) type {
572 const fieldInfos = fields(T);
573 var enumFields: [fieldInfos.len]std.builtin.TypeInfo.EnumField = undefined;
574 var decls = [_]std.builtin.TypeInfo.Declaration{};
575 inline for (fieldInfos) |field, i| {
576 enumFields[i] = .{
577 .name = field.name,
578 .value = i,
579 };
580 }
581 return @Type(.{
582 .Enum = .{
583 .layout = .Auto,
584 .tag_type = std.math.IntFittingRange(0, fieldInfos.len - 1),
585 .fields = &enumFields,
586 .decls = &decls,
587 .is_exhaustive = true,
588 },
589 });
590}
591
592fn expectEqualEnum(expected: anytype, actual: @TypeOf(expected)) void {
593 // TODO: https://github.com/ziglang/zig/issues/7419
594 // testing.expectEqual(@typeInfo(expected).Enum, @typeInfo(actual).Enum);
595 testing.expectEqual(@typeInfo(expected).Enum.layout, @typeInfo(actual).Enum.layout);
596 testing.expectEqual(@typeInfo(expected).Enum.tag_type, @typeInfo(actual).Enum.tag_type);
597 comptime testing.expectEqualSlices(std.builtin.TypeInfo.EnumField, @typeInfo(expected).Enum.fields, @typeInfo(actual).Enum.fields);
598 comptime testing.expectEqualSlices(std.builtin.TypeInfo.Declaration, @typeInfo(expected).Enum.decls, @typeInfo(actual).Enum.decls);
599 testing.expectEqual(@typeInfo(expected).Enum.is_exhaustive, @typeInfo(actual).Enum.is_exhaustive);
600}
601
602test "std.meta.FieldEnum" {
603 expectEqualEnum(enum { a }, FieldEnum(struct { a: u8 }));
604 expectEqualEnum(enum { a, b, c }, FieldEnum(struct { a: u8, b: void, c: f32 }));
605 expectEqualEnum(enum { a, b, c }, FieldEnum(union { a: u8, b: void, c: f32 }));
606}
607
571608pub fn TagType(comptime T: type) type {
572609 return switch (@typeInfo(T)) {
573610 .Enum => |info| info.tag_type,