From cfeeff77833f0e180e116859b2c7370a7c38d8f0 Mon Sep 17 00:00:00 2001
From: Meghan Denny <hello@nektro.net>
Date: Sun, 9 Jul 2023 13:42:05 -0700
Subject: [PATCH] add FieldUnion

---
 src/lib.zig | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/lib.zig b/src/lib.zig
index 7b4c234f38900847a14f7a262f003b9c457ea608..4aa8a5c66eaaae4ae6cf796105556b358ee113aa 100644
--- a/src/lib.zig
+++ b/src/lib.zig
@@ -542,3 +542,22 @@ pub fn to_hex(array: anytype) [array.len * 2]u8 {
     std.fmt.format(fbs.writer(), "{x}", .{std.fmt.fmtSliceHexLower(&array)}) catch unreachable;
     return res;
 }
+
+pub fn FieldUnion(comptime T: type) type {
+    const infos = std.meta.fields(T);
+
+    var fields: [infos.len]std.builtin.Type.UnionField = undefined;
+    inline for (infos, 0..) |field, i| {
+        fields[i] = .{
+            .name = field.name,
+            .type = field.type,
+            .alignment = field.alignment,
+        };
+    }
+    return @Type(std.builtin.Type{ .Union = .{
+        .layout = .Auto,
+        .tag_type = std.meta.FieldEnum(T),
+        .fields = &fields,
+        .decls = &.{},
+    } });
+}
-- 
2.54.0