Alt+click will move the prompt cursor to that position

Fixes #890

src/Terminal.ts

@@ -27,6 +27,7 @@ import { CompositionHelper } from './CompositionHelper';
 import { EventEmitter } from './EventEmitter';
 import { Viewport } from './Viewport';
 import { rightClickHandler, moveTextAreaUnderMouseCursor, pasteHandler, copyHandler } from './handlers/Clipboard';
+import { AltClickHandler } from './handlers/AltClickHandler';
 import { CircularList } from './utils/CircularList';
 import { C0 } from './EscapeSequences';
 import { InputHandler } from './InputHandler';
@@ -953,6 +954,7 @@ export class Terminal extends EventEmitter implements ITerminal, IInputHandlingT
       // if the selection manager is having selection forced (ie. a modifier is
       // held).
       if (!this.mouseEvents || this.selectionManager.shouldForceSelection(ev)) {
+        (new AltClickHandler(ev, this)).move();
         return;
       }
 

src/handlers/AltClickHandler.ts

@@ -0,0 +1,130 @@
+/**
+ * Alt+Click handler module: exports methods for handling all alt+click-related events in the
+ * terminal.
+ * @module xterm/handlers/AltClickHandler
+ * @license MIT
+ */
+
+import { Terminal } from '../Terminal';
+import { CHAR_DATA_WIDTH_INDEX } from '../Buffer';
+import { C0 } from '../EscapeSequences';
+
+export class AltClickHandler {
+  private _terminal: Terminal;
+  private _mouseRow: number;
+  private _mouseCol: number;
+  private _mouseEvent: MouseEvent;
+
+  constructor(mouseEvent: MouseEvent, terminal: Terminal) {
+    this._terminal = terminal;
+
+    [this._mouseCol, this._mouseRow] = this._terminal.mouseHelper.getCoords(
+      (this._mouseEvent = mouseEvent),
+      this._terminal.element,
+      this._terminal.charMeasure,
+      this._terminal.options.lineHeight,
+      this._terminal.cols,
+      this._terminal.rows,
+      true
+    ).map((coordinate: number) => {
+      return coordinate - 1;
+    });
+  }
+
+  public move(): void {
+    if (!this._mouseEvent.altKey) return;
+
+    let keyboardArrows;
+
+    if (this._terminal.buffer === this._terminal.buffers.normal) {
+      keyboardArrows = this.buildArrowSequence(this.normalCharCount(), this.horizontalCursorCommand(this.normalMoveForward()));
+    } else {
+      keyboardArrows = this.buildArrowSequence(this.altVerticalCharCount(), this.verticalCursorCommand(this.altMoveUpward()));
+      keyboardArrows += this.buildArrowSequence(this.altHorizontalCharCount(), this.horizontalCursorCommand(this.altMoveForward()));
+    }
+
+    this._terminal.send(keyboardArrows);
+  }
+
+  private buildArrowSequence(count: number, sequence: string): string {
+    return Array(count).join(sequence);
+  }
+
+  private altMoveUpward(): boolean {
+    return this._terminal.buffer.y > this._mouseRow;
+  }
+
+  private altMoveForward(): boolean {
+    return this._terminal.buffer.x < this._mouseCol;
+  }
+
+  private normalMoveForward(): boolean {
+    return (this._terminal.buffer.x < this._mouseCol &&
+      this._terminal.buffer.y <= this._mouseRow) || // down/right or same row/right
+      (this._terminal.buffer.x >= this._mouseCol &&
+        this._terminal.buffer.y < this._mouseRow);  // down/left or same row/left
+  }
+
+  private horizontalCursorCommand(moveForward: boolean): string {
+    let mod = this._terminal.applicationCursor ? 'O' : '[';
+
+    if (moveForward) {
+      return C0.ESC + mod + 'C';
+    } else {
+      return C0.ESC + mod + 'D';
+    }
+  }
+
+  private verticalCursorCommand(moveUp: boolean): string {
+    let mod = this._terminal.applicationCursor ? 'O' : '[';
+
+    if (moveUp) {
+      return C0.ESC + mod + 'A';
+    } else {
+      return C0.ESC + mod + 'B';
+    }
+  }
+
+  private altVerticalCharCount(): number {
+    return Math.abs(this._terminal.buffer.y - this._mouseRow) + 1;
+  }
+
+  private altHorizontalCharCount(): number {
+    return Math.abs(this._terminal.buffer.x - this._mouseCol) + 1;
+  }
+
+  private normalCharCount(): number {
+    let currentX = this._terminal.buffer.x;
+    let currentY = this._terminal.buffer.y;
+    let startCol = this._terminal.buffer.x;
+    let bufferStr = '';
+
+    while (currentX !== this._mouseCol || (currentY !== this._mouseRow)) {
+      if (this.normalMoveForward()) {
+        currentX++;
+        if (currentX > this._terminal.cols - 1) {
+          bufferStr += this._terminal.buffer.translateBufferLineToString(currentY, false, startCol, currentX);
+          currentX = 0;
+          startCol = 0;
+          currentY++;
+        }
+      } else {
+        currentX--;
+        if (currentX < 0) {
+          bufferStr += this._terminal.buffer.translateBufferLineToString(currentY, false, 0, startCol + 1);
+          currentX = this._terminal.cols - 1;
+          startCol = currentX;
+          currentY--;
+        }
+      }
+    }
+
+    if (this.normalMoveForward()) {
+      currentX++;
+    } else {
+      currentX--;
+    }
+    bufferStr += this._terminal.buffer.translateBufferLineToString(currentY, false, startCol, currentX);
+    return bufferStr.length;
+  }
+}