more lazy evaluation

js/dist/fingertree.js

@@ -260,6 +260,20 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
 		}
 
 		/* js/src/0-core/optimizing */
+		/* js/src/0-core/optimizing/_deepL.js */
+		function _deepL(M, left, middle, right) {
+			return delay(function () {
+				return deepL(M, left, middle, right);
+			});
+		}
+
+		/* js/src/0-core/optimizing/_deepR.js */
+		function _deepR(M, left, middle, right) {
+			return delay(function () {
+				return deepR(M, left, middle, right);
+			});
+		}
+
 		/* js/src/0-core/optimizing/_digit.js */
 		function _digit(list) {
 
@@ -1317,7 +1331,7 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
 					var leftMeasure = M.plus(i, left.measure(M));
 					if (p(leftMeasure)) {
 						var _split = left.splitDigit(p, i, M);
-						return new Split(_from_small_list(M, _split.left), _split.middle, deepL(M, _split.right, middle, right));
+						return new Split(_from_small_list(M, _split.left), _split.middle, _deepL(M, _split.right, middle, right));
 					}
 
 					// see if the split point is inside the middle tree
@@ -1327,12 +1341,12 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
 						var midSplit = middle.splitTree(p, leftMeasure);
 						// midsplit.middle is a Node since middle is a Tree ( Node a )
 						var _split2 = midSplit.middle.digit().splitDigit(p, M.plus(leftMeasure, midSplit.left.measure()), M);
-						return new Split(deepR(M, left, midSplit.left, _split2.left), _split2.middle, deepL(M, _split2.right, midSplit.right, right));
+						return new Split(_deepR(M, left, midSplit.left, _split2.left), _split2.middle, _deepL(M, _split2.right, midSplit.right, right));
 					}
 
 					// the split point is in the right tree
 					var split = right.splitDigit(p, midMeasure, M);
-					return new Split(deepR(M, left, middle, split.left), split.middle, _from_small_list(M, split.right));
+					return new Split(_deepR(M, left, middle, split.left), split.middle, _from_small_list(M, split.right));
 				}
 			}, {
 				key: 'split',

js/src/0-core/optimizing/_deepL.js

@@ -0,0 +1,3 @@
+function _deepL ( M , left , middle , right ) {
+	return delay( ( ) => deepL( M , left , middle , right ) ) ;
+}

js/src/0-core/optimizing/_deepR.js

@@ -0,0 +1,3 @@
+function _deepR ( M , left , middle , right ) {
+	return delay( ( ) => deepR( M , left , middle , right ) ) ;
+}

js/src/3-tree/1-base/2-Deep.js

@@ -135,7 +135,7 @@ class Deep extends Tree {
 			return new Split(
 				_from_small_list( M , split.left ) ,
 				split.middle ,
-				deepL( M , split.right , middle , right )
+				_deepL( M , split.right , middle , right )
 			) ;
 		}
 
@@ -147,16 +147,16 @@ class Deep extends Tree {
 			// midsplit.middle is a Node since middle is a Tree ( Node a )
 			const split = midSplit.middle.digit( ).splitDigit( p , M.plus( leftMeasure , midSplit.left.measure( ) ) , M ) ;
 			return new Split(
-				deepR( M , left , midSplit.left, split.left ) ,
+				_deepR( M , left , midSplit.left, split.left ) ,
 				split.middle ,
-				deepL( M , split.right , midSplit.right , right )
+				_deepL( M , split.right , midSplit.right , right )
 			) ;
 		}
 
 		// the split point is in the right tree
 		const split = right.splitDigit( p , midMeasure , M ) ;
 		return new Split(
-			deepR( M , left , middle , split.left ) ,
+			_deepR( M , left , middle , split.left ) ,
 			split.middle ,
 			_from_small_list( M , split.right )
 		) ;