Fix minor issue and add utilities

Author: sebastienfilion

library/Either.js

@@ -52,7 +52,7 @@ Either.prototype.alt = Either.prototype["fantasy-land/alt"] = function (containe
 Either.prototype.ap = Either.prototype["fantasy-land/ap"] = function (container) {
 
   return this.fold({
-    Left: _ => container,
+    Left: _ => this,
     Right: value => Either.Right.is(container) ? Either.Right(container[$$value](value)) : container
   });
 };

library/Pair.js

@@ -1,3 +1,5 @@
+import { curry } from "https://x.nest.land/[email protected]/source/index.js";
+
 import { factorizeType } from "./factories.js";
 
 /**
@@ -34,4 +36,6 @@ Pair.prototype.map = Pair.prototype["fantasy-land/map"] = function (unaryFunctio
   return Pair(unaryFunction(this.first), this.second);
 };
 
+export const factorizePair = curry(Pair);
+
 export default Pair;

library/Task.js

@@ -4,6 +4,7 @@ import Pair from "./Pair.js";
 import { Done, Loop } from "./Step.js";
 
 import { $$debug, $$inspect } from "./Symbols.js";
+import { chainLift } from "./utilities.js";
 
 const concat = x => y => x.concat(y);
 
@@ -173,12 +174,6 @@ Task.prototype.chain = Task.prototype["fantasy-land/chain"] = function (unaryFun
   );
 };
 
-// chainLift :: Task a -> Task b -> (a -> b -> c) -> Task c
-const chainLift = (chainableFunctor, functor, binaryFunction) => {
-
-  return chainableFunctor.chain(x => functor.map(binaryFunction(x)));
-}
-
 Task.prototype.chainRec = Task.prototype["fantasy-land/chainRec"] = function (ternaryFunction, initialCursor) {
   let accumulator = this;
   let result = Loop(Pair(initialCursor, null));
@@ -187,7 +182,7 @@ Task.prototype.chainRec = Task.prototype["fantasy-land/chainRec"] = function (te
     result = ternaryFunction(Loop, Done, result.value.first);
 
     if (Loop.is(result)) {
-      accumulator = chainLift(accumulator, result.value.second, concat);
+      accumulator = chainLift(concat, accumulator, result.value.second);
     }
   }
 

library/utilities.js

@@ -18,6 +18,16 @@ export const assertIsUndefined = value => value === undefined;
 export const decodeRaw = $$decoder.decode.bind($$decoder);
 export const encodeText = $$encoder.encode.bind($$encoder);
 
+// chainLift :: (a -> b -> c) -> Task a -> Task b -> Task c
+export const chainLift = curry(
+  (binaryFunction, chainableFunctor, functor) => chainableFunctor.chain(x => functor.map(binaryFunction(x)))
+);
+
+// chainRec :: (a -> c, b -> c, a) -> a -> Task b -> Task c
+export const chainRec = curry(
+  (ternaryFunction, initiator, task) => task.chainRec(ternaryFunction, initiator)
+);
+
 // insideOut :: Applicative a => a -> a[] -> a
 export const insideOut = curry(
   (T, list) => list.reduce(