add primitive string type

lib/structures/enum.types.js

@@ -5,34 +5,6 @@ import { makeConstructors, makeMatchFn } from "./enum.js";
 import { getLeft, getRight } from "./product.js";
 import { fnType } from "./type_constructors.types.js";
 
-// 'variants' is an array of (name: string, type: Type) pairs.
-// e.g., the list of variants:
-//   [ { l: "price"    , r: Int   },
-//     { l: "prices"   , r: [Int] },
-//     { l: "not_found", r: Unit  }  ]
-// results in the type:
-//   (Int | ([Int] | (Unit | ⊥)))
-
-// const _enumType = rootSelf => variants => {
-//   // console.log("enumType..", variants);
-//   if (variants.length === 0) {
-//     return Bottom; // empty enum is equal to Bottom-type (cannot be instantiated)
-//   }
-//   const [variant, ...rest] = variants;
-//   const variantType = getRight(variant);
-//   return sumType
-//     (self => {
-//       // console.log("requested left type (of enumType)")
-//       return variantType(rootSelf || self);
-//     })
-//     (self => {
-//       // console.log("requested right type (of enumType)")
-//       return _enumType(self)(rest)
-//     });
-// };
-
-// export const enumType = _enumType(null);
-
 export const makeConstructorTypes = type => variants => {
   return variants.map(variant => {
     const variantType = getRight(variant);