feat: Newline command

css/core.less

@@ -210,6 +210,10 @@
   padding: 0 0.5em;
 }
 
+.ML__newline {
+  display: block;
+}
+
 .ML__frac-line {
   width: 100%;
   min-height: 1px;

src/addons/definitions-metadata.ts

@@ -1040,6 +1040,7 @@ metadata(
   RARE,
   '\\unicode{"203A}$0{1em}\\unicode{"2039}'
 );
+metadata('Spacing', ['\\\\'], COMMON); // New Line
 metadata(
   'Punctuation',
   [

src/addons/math-ml.ts

@@ -728,6 +728,10 @@ function atomToMathML(atom, options): string {
       case 'overlap':
         break;
 
+      case 'newline':
+        result += '<mspace linebreak="newline"></mspace>';
+        break;
+
       case 'overunder':
         overscript = atom.above;
         underscript = atom.below;

src/core-atoms/newline.ts

@@ -0,0 +1,35 @@
+import { Atom, AtomJson } from '../core/atom-class';
+import { Box } from '../core/box';
+import { Context } from '../core/context';
+
+import type { ParseMode, Style } from '../public/core-types';
+import type { GlobalContext } from '../core/types';
+
+export class NewLineAtom extends Atom {
+  constructor(command: string, context: GlobalContext, style: Style) {
+    super('newline', context, { command, style });
+    this.skipBoundary = true;
+  }
+
+  static fromJson(json: AtomJson, context: GlobalContext): NewLineAtom {
+    return new NewLineAtom(json.command, context, json as any);
+  }
+
+  toJson(): AtomJson {
+    return super.toJson();
+  }
+
+  render(context: Context): Box | null {
+    const box = new Box(null, {
+      classes: 'ML__newline',
+      type: 'newline',
+    });
+    box.caret = (this.caret as ParseMode) ?? null;
+    this.bind(context, box);
+    return box;
+  }
+
+  serialize(): string {
+    return '\\\\';
+  }
+}

src/core-definitions/styling.ts

@@ -26,6 +26,7 @@ import type {
 import { GlobalContext, PrivateStyle } from '../core/types';
 import { latexCommand } from '../core/tokenizer';
 import { atomsBoxType } from '../core/box';
+import { NewLineAtom } from '../core-atoms/newline';
 
 defineFunction('mathtip', '{:math}{:math}', {
   createAtom: (
@@ -818,6 +819,12 @@ defineFunction('mspace', '{width:glue}', {
     ),
 });
 
+// New line
+defineFunction('\\', '', {
+  createAtom: (command, context, style) =>
+    new NewLineAtom(command, context, style),
+});
+
 defineFunction('mathop', '{:auto}', {
   createAtom: (
     name: string,

src/core/atom-class.ts

@@ -107,6 +107,7 @@ export type AtomType =
   | 'leftright' // Used by the `\left` and `\right` commands
   | 'line' // Used by `\overline` and `\underline`
   | 'macro'
+  | 'newline' // New line command: `\\`
   | 'subsup' // A carrier for a superscript/subscript
   | 'overlap' // Display a symbol _over_ another
   | 'overunder' // Displays an annotation above or below a symbol
@@ -565,6 +566,16 @@ export class Atom {
     return false;
   }
 
+  get isInArrayAtom(): boolean {
+    // eslint-disable-next-line @typescript-eslint/no-this-alias
+    let atom: Atom | undefined = this;
+    while (atom) {
+      if (atom.type === 'array') return true;
+      atom = atom.parent;
+    }
+    return false;
+  }
+
   /** Return the parent editable prompt, if it exists */
   get parentPrompt(): Atom | null {
     // eslint-disable-next-line @typescript-eslint/no-this-alias

src/core/atom.ts

@@ -30,6 +30,7 @@ import { SurdAtom } from '../core-atoms/surd';
 import { TextAtom } from '../core-atoms/text';
 import { TooltipAtom } from '../core-atoms/tooltip';
 import { PromptAtom } from '../core-atoms/prompt';
+import { NewLineAtom } from '../core-atoms/newline';
 import type { GlobalContext } from '../core/types';
 
 export * from './atom-class';
@@ -69,6 +70,7 @@ export function fromJson(
   if (type === 'leftright') result = LeftRightAtom.fromJson(json, context);
   if (type === 'line') result = LineAtom.fromJson(json, context);
   if (type === 'macro') result = MacroAtom.fromJson(json, context);
+  if (type === 'newline') result = NewLineAtom.fromJson(json, context);
   if (type === 'subsup') result = SubsupAtom.fromJson(json, context);
   if (type === 'overlap') result = OverlapAtom.fromJson(json, context);
   if (type === 'overunder') result = OverunderAtom.fromJson(json, context);

src/core/box.ts

@@ -764,6 +764,7 @@ function applyInterAtomSpacing(root: Box | null, context: Context): void {
     if (!prevBox?.type) return;
     // console.log(prevBox?.value, prevBox?.type, box.value, box.type);
     const prevType = prevBox.type;
+    if (prevType === 'newline') return;
     const table = box.isTight
       ? INTER_BOX_TIGHT_SPACING[prevType] ?? null
       : INTER_BOX_SPACING[prevType] ?? null;

src/core/types.ts

@@ -88,6 +88,7 @@ const BOX_TYPE = [
   'close', // > is a closing atom like `)`
   'punct', // > is a punctuation atom like ‘,’
   'inner', // >  is an inner atom like `\frac12`
+  'newline', // >  is a new line box
   'spacing',
   'first',
   'latex',

src/editor-mathfield/mathfield-private.ts

@@ -1072,11 +1072,12 @@ If you are using Vue, this may be because you are using the runtime-only build o
 
     if (options.scrollIntoView) this.scrollIntoView();
 
-    if (s === '\\\\') {
-      // This string is interpreted as an "insert row after" command
-      addRowAfter(this.model);
-    } else if (s === '&') addColumnAfter(this.model);
-    else {
+    if (this.model.at(this.model.position).isInArrayAtom) {
+      if (s === '\\\\') {
+        // This string is interpreted as an "insert row after" command
+        addRowAfter(this.model);
+      } else if (s === '&') addColumnAfter(this.model);
+    } else {
       const savedStyle = this.style;
       ModeEditor.insert(this.mode, this.model, s, {
         style: this.model.at(this.model.position).computedStyle,

src/editor/keybindings-definitions.ts

@@ -87,6 +87,9 @@ export const DEFAULT_KEYBINDINGS: Keybinding[] = [
   }, // Complete the suggestion
   { key: '[Return]', ifMode: 'latex', command: 'complete' },
   { key: '[Enter]', ifMode: 'latex', command: 'complete' },
+  { key: '[Return]', ifMode: 'math', command: ['insert', '\\\\'] },
+  { key: '[Enter]', ifMode: 'math', command: ['insert', '\\\\'] },
+  { key: '[NumpadEnter]', ifMode: 'math', command: ['insert', '\\\\'] },
   {
     key: 'shift+[Escape]',
     ifMode: 'latex',

src/virtual-keyboard/data.ts

@@ -135,7 +135,7 @@ export const LAYOUTS: Record<string, VirtualKeyboardLayout> = {
         '[separator-5]',
         '[left]',
         '[right]',
-        { label: '[action]', width: 1.0 },
+        { label: '[return]', width: 1.0 },
       ],
     ],
   },
@@ -372,7 +372,7 @@ export const LAYOUTS: Record<string, VirtualKeyboardLayout> = {
 
         '[left]',
         '[right]',
-        '[action]',
+        '[return]',
       ],
     ],
   },
@@ -660,7 +660,7 @@ export const LAYOUTS: Record<string, VirtualKeyboardLayout> = {
           width: 1.0,
           class: 'action hide-shift',
         },
-        { label: '[action]', width: 1.0 },
+        { label: '[return]', width: 1.0 },
       ],
     ],
   },

src/virtual-keyboard/utils.ts

@@ -177,7 +177,7 @@ function alphabeticLayout(): NormalizedVirtualKeyboardLayout {
     '[.]',
     '[left]',
     '[right]',
-    { label: '[action]', width: 1.5 },
+    { label: '[return]', width: 1.5 },
   ]);
 
   return {
@@ -735,7 +735,8 @@ const KEYCAP_SHORTCUTS: Record<string, Partial<VirtualKeyboardKeycap>> = {
   },
   '[return]': {
     class: 'action',
-    command: ['performWithFeedback', 'commit'],
+    insert: '\\\\',
+    shift: { command: ['performWithFeedback', 'commit'] },
     width: 1.5,
     label: '<svg class=svg-glyph><use xlink:href=#svg-commit /></svg>',
   },