add String type + use String to make nominal types unique (worse, but more pleasant when debugging)

lib/point.js

@@ -1,17 +1,21 @@
 import { Function, Type } from "../metacircular.js";
 import { Double } from "../primitives/symbols.js";
+import { String } from "../structures/list_types/string.js";
 import { nominalType, NominalType } from "../structures/nominal_type.js";
+import { makeProductType } from "../structures/product.js";
 import { fnType, prodType, typedFnType } from "../type_registry.js";
 
 const PointCartesian2D = nominalType(
   // just a unique number, to make sure that our type is only equal to itself
-  BigInt("0xBBAAD62B10EE21993BA690A732DA2A6875CE4B6F5E7139D5AEC9FD887F9D24A8"))
-  (prodType(Double, Double));
+  "PointCartesian2D")
+  // BigInt("0xBBAAD62B10EE21993BA690A732DA2A6875CE4B6F5E7139D5AEC9FD887F9D24A8"))
+  (prodType(String, Double));
 
 const PointPolar2D = nominalType(
   // just a unique number, to make sure that our type is only equal to itself
-  BigInt("0x31CDAB4B3D84C4EB27D3C111FD7580E533268B72E05BD694F8B262913E018B72"))
-  (prodType(Double, Double));
+  "PointPolar2D")
+  // BigInt("0x31CDAB4B3D84C4EB27D3C111FD7580E533268B72E05BD694F8B262913E018B72"))
+  (prodType(String, Double));
 
 export const cart2polar = ({left: x, right: y}) => {
   const r = Math.sqrt(x*x + y*y);
@@ -37,10 +41,15 @@ export const scale = dr => ({left: r, right: θ}) => {
   return {left: r+dr, right: θ};
 }
 
+const examplePoint = {left: 1, right: 2};
+
 export const ModulePoint = {l:[
   {i: -1                 , t: Double},
   {i: 2                  , t: Double},
-  {i: {left: 1, right: 2}, t: PointCartesian2D},
+  {i: examplePoint       , t: PointCartesian2D},
+  {i: examplePoint       , t: prodType(Double, Double)},
+
+  ...makeProductType(Double, Double).l,
 
   {i: PointCartesian2D   , t: NominalType},
   {i: PointPolar2D       , t: NominalType},

lib/square.js

@@ -1,5 +1,5 @@
 import {Function, getIn, getOut} from "../metacircular.js";
-import {Module} from "../structures/module.js";
+import {Module} from "../structures/list_types/module.js";
 import { deepEqual } from "../util.js";
 import { Typed } from "../typed.js";
 import { fnType } from "../type_registry.js";

main.js

@@ -7,7 +7,7 @@ import { makeSquare } from "./lib/square.js";
 import {makeIdFn} from "./lib/id.js";
 
 import {DefaultMap, pretty} from "./util.js";
-import { ModuleModule } from "./structures/module.js";
+import { ModuleModule } from "./structures/list_types/module.js";
 import { ModuleList } from "./structures/list.js";
 import {Int, Bool, Double, Byte} from "./primitives/symbols.js";
 import { makeListModule } from "./structures/list_common.js";

primitives/char.js

@@ -0,0 +1,11 @@
+import { typedFnType } from "../type_registry.js";
+import {Type} from "../metacircular.js";
+import {Char, Bool} from "./symbols.js";
+
+const eq = x => y => x === y;
+
+export const ModuleChar = {l:[
+  {i: Char, t: Type},
+
+  ...typedFnType(eq, fnType => fnType({in: Char, out: fnType({in: Char, out: Bool})})),
+]};

primitives/symbols.js

@@ -3,4 +3,5 @@
 export const Bool = Symbol('Bool');
 export const Int = Symbol('Int');
 export const Double = Symbol('Double');
-export const Byte = Symbol('Byte');
+export const Byte = Symbol('Byte');
+export const Char = Symbol('Char');

structures/list.js

@@ -1,7 +1,7 @@
 import { fnType, lsType } from "../type_registry.js";
 import {Type, Function} from "../metacircular.js";
 import { makeListModule } from "./list_common.js";
-import { Module } from "./module.js";
+import { Module } from "./list_types/module.js";
 
 const Type_to_Type = fnType({in: Type, out: Type});
 const Type_to_Module = fnType({in: Type, out: Module});

structures/list_types/module.js

@@ -1,6 +1,6 @@
-import { makeListModule } from "./list_common.js";
-import { Typed } from "../typed.js";
-import { lsType } from "../type_registry.js";
+import { makeListModule } from "../list_common.js";
+import { Typed } from "../../typed.js";
+import { lsType } from "../../type_registry.js";
 
 export const Module = lsType(Typed); // a Module is a list of Typeds
 

structures/list_types/string.js

@@ -0,0 +1,7 @@
+import { Char } from "../../primitives/symbols.js";
+import { lsType } from "../../type_registry.js";
+import { makeListModule } from "../list_common.js";
+
+export const String = lsType(Char);
+
+export const ModuleString = makeListModule(Char);

structures/sum.js

@@ -1,6 +1,6 @@
 import { fnType, prodType, sumType } from "../type_registry.js";
 import { Function, Type } from "../metacircular.js";
-import { Module } from "./module.js";
+import { Module } from "./list_types/module.js";
 
 const constructorLeft  = left  => ({variant: "L", value: left });
 const constructorRight = right => ({variant: "R", value: right});