| 1 | const std = @import("std"); |
| 2 | const string = []const u8; |
| 3 | const extras = @import("./lib.zig"); |
| 4 | const expectSimilarType = extras.expectSimilarType; |
| 5 | |
| 6 | pub fn FieldUnion(comptime T: type) type { |
| 7 | const fields = std.meta.fields(T); |
| 8 | var names: [fields.len][]const u8 = undefined; |
| 9 | var types: [fields.len]type = undefined; |
| 10 | var attrs: [fields.len]std.builtin.Type.UnionField.Attributes = undefined; |
| 11 | |
| 12 | inline for (fields, 0..) |field, i| { |
| 13 | names[i] = field.name; |
| 14 | types[i] = field.type; |
| 15 | attrs[i] = .{ .@"align" = field.alignment }; |
| 16 | } |
| 17 | return @Union(.auto, std.meta.FieldEnum(T), &names, &types, &attrs); |
| 18 | } |
| 19 | |
| 20 | test { |
| 21 | try expectSimilarType( |
| 22 | FieldUnion(struct { |
| 23 | a: u32, |
| 24 | b: u8, |
| 25 | c: u16, |
| 26 | }), |
| 27 | union(enum) { |
| 28 | a: u32, |
| 29 | b: u8, |
| 30 | c: u16, |
| 31 | }, |
| 32 | ); |
| 33 | } |