progress and some refactoring

structures/set.js

@@ -0,0 +1,38 @@
+import { setType, typedFnType } from "./types.js";
+import { Bool, Type } from "../primitives/types.js";
+import { makeGeneric } from "../generics/generics.js";
+
+// 'normal' implementation
+const emptySet = new Set();
+const has = set => elem => set.has(elem);
+const add = set => elem => new Set([...set, elem]);
+
+export const ModuleList = {l:[
+  // Type -> Type
+  ...typedFnType(setType, fnType =>
+    fnType
+      /* in  */ (Type)
+      /* out */ (Type)
+  ),
+
+  {i: emptySet, t: makeGeneric(a => setType(a))},
+
+  ...typedFnType(has, fnType =>
+    makeGeneric(a =>
+      fnType
+        /* in  */ (setType(a))
+        /* out */ (fnType
+          /* in  */ (a)
+          /* out */ (Bool)
+        ))),
+
+  ...typedFnType(add, fnType =>
+    makeGeneric(a =>
+      fnType
+        /* in  */ (setType(a))
+        /* out */ (fnType
+          /* in  */ (a)
+          /* out */ (setType(a))
+        ))),
+
+]};