More deduping of builtins, fix todo

valuescript_common/src/builtins.rs

@@ -1 +1,19 @@
-pub const BUILTIN_NAMES: [&str; 4] = ["Debug", "Math", "String", "Number"];
+use strum::EnumCount;
+
+#[derive(strum_macros::EnumString, strum_macros::EnumCount, Clone, Copy)]
+pub enum BuiltinName {
+  Debug,
+  Math,
+  String,
+  Number,
+}
+
+pub const BUILTIN_NAMES: [&str; BuiltinName::COUNT] = ["Debug", "Math", "String", "Number"];
+
+pub const BUILTIN_COUNT: usize = BuiltinName::COUNT;
+
+impl BuiltinName {
+  pub fn to_code(&self) -> usize {
+    *self as usize
+  }
+}