Add meta.zig

src/image.zig

@@ -1,7 +1,7 @@
 const std = @import("std");
 const Allocator = std.mem.Allocator;
 const Rgba = @import("color.zig").Rgba;
-const as = @import("utils.zig").as;
+const as = @import("meta.zig").as;
 
 /// A simple image struct that encapsulates the size and the data.
 pub fn Image(comptime T: type) type {

src/meta.zig

@@ -0,0 +1,27 @@
+/// Converts between numeric types: .Enum, .Int and .Float.
+pub inline fn as(comptime T: type, from: anytype) T {
+    switch (@typeInfo(@TypeOf(from))) {
+        .Enum => {
+            switch (@typeInfo(T)) {
+                .Int => return @intFromEnum(from),
+                else => @compileError(@typeName(@TypeOf(from)) ++ " can't be converted to " ++ @typeName(T)),
+            }
+        },
+        .Int => {
+            switch (@typeInfo(T)) {
+                .Enum => return @enumFromInt(from),
+                .Int => return @intCast(from),
+                .Float => return @floatFromInt(from),
+                else => @compileError(@typeName(@TypeOf(from)) ++ " can't be converted to " ++ @typeName(T)),
+            }
+        },
+        .Float => {
+            switch (@typeInfo(T)) {
+                .Float => return @floatCast(from),
+                .Int => return @intFromFloat(from),
+                else => @compileError(@typeName(@TypeOf(from)) ++ " can't be converted to " ++ @typeName(T)),
+            }
+        },
+        else => @compileError(@typeName(@TypeOf(from) ++ " is not supported.")),
+    }
+}