new RESHAPE primitive

HISTORY.md

@@ -9,6 +9,9 @@
 * **Documentation Updates:**
     * updated manual (e.g. p.20) with hyper-semantics of ITEM OF, thanks Brian 
 
+### 2021-02-06
+* lists, objects, threads: new RESHAPE primitive
+
 ### 2021-02-06
 * simplified private list.range() method
 * blocks: changed wordings for list attributes

snap.html

@@ -9,11 +9,11 @@
         <script src="src/symbols.js?version=2020-10-07"></script>
         <script src="src/widgets.js?version=2021-01-05"></script>
         <script src="src/blocks.js?version=2021-02-07"></script>
-        <script src="src/threads.js?version=2021-02-07"></script>
-        <script src="src/objects.js?version=2021-01-30"></script>
+        <script src="src/threads.js?version=2021-02-08"></script>
+        <script src="src/objects.js?version=2021-02-08"></script>
         <script src="src/gui.js?version=2021-02-04"></script>
         <script src="src/paint.js?version=2020-05-17"></script>
-        <script src="src/lists.js?version=2021-02-07"></script>
+        <script src="src/lists.js?version=2021-02-08"></script>
         <script src="src/byob.js?version=2020-12-22"></script>
         <script src="src/tables.js?version=2020-10-06"></script>
         <script src="src/sketch.js?version=2020-07-13"></script>

src/lists.js

@@ -63,7 +63,7 @@ MorphicPreferences, TableDialogMorph, SpriteBubbleMorph, SpeechBubbleMorph,
 TableFrameMorph, TableMorph, Variable, isSnapObject, Costume, contains, detect,
 ZERO, WHITE*/
 
-modules.lists = '2021-February-07';
+modules.lists = '2021-February-08';
 
 var List;
 var ListWatcherMorph;
@@ -121,6 +121,7 @@ var ListWatcherMorph;
     flatten()               - answer a concatenated list of columns and atoms
     ravel()                 - answer a flat list of all atoms in all sublists
     transpose()             - answer a 2D list with rows turned into columns
+    reshape()               - answer a new list formatted to the given dimensions.
     query()                 - answer a part of a list or multidimensionel struct
 */
 
@@ -582,6 +583,60 @@ List.prototype.transpose = function () {
     return new List(table);
 };
 
+List.prototype.reshape = function (dimensions) {
+    // answer a new list formatted to fit the given dimensions.
+    // truncate excess elements, if any.
+    // pad with (repetitions of) existing elements
+    var src = this.ravel().itemsArray(),
+        size = dimensions.isEmpty() ? 0
+            : dimensions.itemsArray().reduce((a, b) => a * b),
+        i = 0,
+        trg;
+
+    if (size < src.length) {
+        trg = src.slice(0, size);
+    } else {
+        trg = src.slice();
+        while (trg.length < size) {
+            if (i >= src.length) {
+                i = 0;
+            }
+            trg.push(src[i]);
+            i += 1;
+        }
+    }
+    return new List(trg).folded(dimensions).at(1);
+};
+
+List.prototype.folded = function (dimensions) {
+    // private
+    var len = dimensions.length(),
+        trg = this,
+        i;
+    if (len == 0) {
+        return this.map(e => e);
+    }
+    for (i = len; i > 0; i -= 1) {
+        trg = trg.asChunksOf(dimensions.at(i));
+    }
+    return trg;
+};
+
+List.prototype.asChunksOf = function (size) {
+    // private
+    var trg = new List(),
+        len = this.length(),
+        sub, i;
+    for (i = 0; i < len; i += 1) {
+        if (i % size === 0) {
+            sub = new List();
+            trg.add(sub);
+        }
+        sub.add(this.at(i + 1));
+    }
+    return trg;
+};
+
 // List conversion:
 
 List.prototype.asArray = function () {

src/objects.js

@@ -84,7 +84,7 @@ BlockEditorMorph, BlockDialogMorph, PrototypeHatBlockMorph,  BooleanSlotMorph,
 localize, TableMorph, TableFrameMorph, normalizeCanvas, VectorPaintEditorMorph,
 AlignmentMorph, Process, WorldMap, copyCanvas, useBlurredShadows*/
 
-modules.objects = '2021-February-05';
+modules.objects = '2021-February-08';
 
 var SpriteMorph;
 var StageMorph;
@@ -1391,11 +1391,16 @@ SpriteMorph.prototype.initBlocks = function () {
             category: 'lists',
             spec: 'append %lists'
         },
-        reportTranspose: {
+        reportTranspose: { // deprecated
             type: 'reporter',
             category: 'lists',
             spec: 'transpose %l'
         },
+        reportReshape: {
+            type: 'reporter',
+            category: 'lists',
+            spec: 'reshape %l to %mult%n'
+        },
 
         // HOFs
         reportMap: {
@@ -2780,6 +2785,7 @@ SpriteMorph.prototype.blockTemplates = function (category) {
         blocks.push(block('doForEach'));
         blocks.push('-');
         blocks.push(block('reportConcatenatedLists'));
+        blocks.push(block('reportReshape'));
         // blocks.push(block('reportTranspose'));
         blocks.push('-');
         blocks.push(block('doAddToList'));
@@ -2957,6 +2963,7 @@ SpriteMorph.prototype.freshPalette = function (category) {
                         'reportListAttribute',
                         'reportListIndex',
                         'reportConcatenatedLists',
+                        'reportReshape',
                         'reportListContainsItem',
                         'reportListIsEmpty',
                         'doForEach',
@@ -8940,6 +8947,7 @@ StageMorph.prototype.blockTemplates = function (category) {
         blocks.push(block('doForEach'));
         blocks.push('-');
         blocks.push(block('reportConcatenatedLists'));
+        blocks.push(block('reportReshape'));
         // blocks.push(block('reportTranspose'));
         blocks.push('-');
         blocks.push(block('doAddToList'));

src/threads.js

@@ -61,7 +61,7 @@ StageMorph, SpriteMorph, StagePrompterMorph, Note, modules, isString, copy, Map,
 isNil, WatcherMorph, List, ListWatcherMorph, alert, console, TableMorph, BLACK,
 TableFrameMorph, ColorSlotMorph, isSnapObject, newCanvas, Symbol, SVG_Costume*/
 
-modules.threads = '2021-February-07';
+modules.threads = '2021-February-08';
 
 var ThreadManager;
 var Process;
@@ -1948,13 +1948,19 @@ Process.prototype.reportListItem = function (index, list) {
     return list.at(index);
 };
 
-// Process - experimental tabular list accessors
+// Process - experimental tabular list ops
 
 Process.prototype.reportTranspose = function (list) {
     this.assertType(list, 'list');
     return list.transpose();
 };
 
+Process.prototype.reportReshape = function (list, shape) {
+    this.assertType(list, 'list');
+    this.assertType(shape, 'list');
+    return list.reshape(shape);
+};
+
 // Process - other basic list accessors
 
 Process.prototype.reportListAttribute = function (choice, list) {