diff --git a/source/coral/io.zig b/source/coral/io.zig
index 7961cfc..deba662 100755
--- a/source/coral/io.zig
+++ b/source/coral/io.zig
@@ -84,6 +84,14 @@ pub const Reader = struct {
 	}
 };
 
+pub fn Tag(comptime Element: type) type {
+	return switch (@typeInfo(Element)) {
+		.Enum => |info| info.tag_type,
+		.Union => |info| info.tag_type orelse @compileError(@typeName(Element) ++ " has no tag type"),
+		else => @compileError("expected enum or union type, found '" ++ @typeName(Element) ++ "'"),
+	};
+}
+
 pub const WriteError = error{
 	IoUnavailable,
 };