feat(core): Add in functionality for double-click word selection and triple-click line selection

packages/core/src/renderables/EditBufferRenderable.ts

@@ -610,6 +610,74 @@ export abstract class EditBufferRenderable extends Renderable implements LineInf
     this.setSelection(Math.min(start, end), Math.max(start, end) + 1)
   }
 
+  selectWordAt(x: number, y: number): void {
+    if (!this.moveCursorToMousePosition(x, y)) return
+
+    // Native word-boundary navigation is broader than double-click semantics
+    // here, so select the contiguous word-token under the clicked cell instead.
+    const cursor = this.editBuffer.getCursorPosition()
+    const selection = this.getWordSelectionAtOffset(cursor.offset)
+    if (!selection) {
+      this.clearSelection()
+      return
+    }
+
+    this.setSelection(selection.start, selection.end)
+  }
+
+  private getWordSelectionAtOffset(offset: number): { start: number; end: number } | null {
+    if (offset < 0) return null
+
+    // EditBuffer offsets are display-width offsets; avoid JS string length for bounds checks.
+    const initial = this.editBuffer.getTextRange(offset, offset + 1)
+    if (!this.isWordSelectionText(initial)) return null
+
+    let start = offset
+    let end = start + 1
+
+    // Expand over the same token class in both directions. Punctuation and
+    // whitespace intentionally stop expansion instead of joining nearby words.
+    while (start > 0 && this.isWordSelectionText(this.editBuffer.getTextRange(start - 1, start))) {
+      start -= 1
+    }
+
+    while (this.isWordSelectionText(this.editBuffer.getTextRange(end, end + 1))) {
+      end += 1
+    }
+
+    return { start, end }
+  }
+
+  private isWordSelectionText(text: string): boolean {
+    // Keep underscores with identifiers while treating punctuation as a boundary.
+    return /^[\p{L}\p{N}_]$/u.test(text)
+  }
+
+  selectLineAt(x: number, y: number): void {
+    if (!this.moveCursorToMousePosition(x, y)) return
+
+    const cursor = this.editBuffer.getCursorPosition()
+    const start = this.editBuffer.getLineStartOffset(cursor.row)
+    const end = this.editBuffer.getEOL()
+
+    this.setSelection(start, end.offset)
+  }
+
+  private moveCursorToMousePosition(x: number, y: number): boolean {
+    if (!this.shouldStartSelection(x, y)) return false
+
+    const localX = x - this.x
+    const localY = y - this.y
+    // Reuse editor-view local selection mapping to place the logical cursor at
+    // the clicked cell, then clear the temporary local selection immediately.
+    this.editorView.setLocalSelection(localX, localY, localX, localY, this._selectionBg, this._selectionFg, true)
+
+    this.editorView.resetLocalSelection()
+    this.lastLocalSelection = null
+
+    return true
+  }
+
   clearSelection(): boolean {
     const had = this.hasSelection()
     this.lastLocalSelection = null

packages/core/src/renderables/__tests__/Textarea.selection.test.ts

@@ -51,6 +51,83 @@ describe("Textarea - Selection Tests", () => {
       expect(editor.getSelectedText()).toBe("Hello")
     })
 
+    it("should select a word on double click", async () => {
+      const { textarea: editor } = await createTextareaRenderable(currentRenderer, renderOnce, {
+        initialValue: "Hello World",
+        width: 40,
+        height: 10,
+        selectable: true,
+      })
+
+      await currentMouse.doubleClick(editor.x + 1, editor.y)
+      await renderOnce()
+
+      expect(editor.getSelectedText()).toBe("Hello")
+      expect(editor.getSelection()).toEqual({ start: 0, end: 5 })
+    })
+
+    it("should select only the clicked word at punctuation boundaries", async () => {
+      const { textarea: editor } = await createTextareaRenderable(currentRenderer, renderOnce, {
+        initialValue: "Emacs-style)",
+        width: 40,
+        height: 10,
+        selectable: true,
+      })
+
+      await currentMouse.doubleClick(editor.x + 6, editor.y)
+      await renderOnce()
+
+      expect(editor.getSelectedText()).toBe("style")
+      expect(editor.getSelection()).toEqual({ start: 6, end: 11 })
+    })
+
+    it("should not include the previous word when double clicking the first letter", async () => {
+      const { textarea: editor } = await createTextareaRenderable(currentRenderer, renderOnce, {
+        initialValue: "Hello World",
+        width: 40,
+        height: 10,
+        selectable: true,
+      })
+
+      await currentMouse.doubleClick(editor.x + 6, editor.y)
+      await renderOnce()
+
+      expect(editor.getSelectedText()).toBe("World")
+      expect(editor.getSelection()).toEqual({ start: 6, end: 11 })
+    })
+
+    it("should not select adjacent words when double clicking whitespace", async () => {
+      const { textarea: editor } = await createTextareaRenderable(currentRenderer, renderOnce, {
+        initialValue: "Hello World",
+        width: 40,
+        height: 10,
+        selectable: true,
+      })
+
+      await currentMouse.doubleClick(editor.x + 5, editor.y)
+      await renderOnce()
+
+      expect(editor.hasSelection()).toBe(false)
+      expect(editor.getSelectedText()).toBe("")
+    })
+
+    it("should select a line on triple click", async () => {
+      const { textarea: editor } = await createTextareaRenderable(currentRenderer, renderOnce, {
+        initialValue: "First\nSecond line\nThird",
+        width: 40,
+        height: 10,
+        selectable: true,
+      })
+
+      await currentMouse.click(editor.x + 3, editor.y + 1)
+      await currentMouse.click(editor.x + 3, editor.y + 1)
+      await currentMouse.click(editor.x + 3, editor.y + 1)
+      await renderOnce()
+
+      expect(editor.getSelectedText()).toBe("Second line")
+      expect(editor.getSelection()).toEqual({ start: 6, end: 17 })
+    })
+
     it("should return selected text from multi-line content", async () => {
       const { textarea: editor } = await createTextareaRenderable(currentRenderer, renderOnce, {
         initialValue: "AAAA\nBBBB\nCCCC",

packages/core/src/renderer.ts

@@ -828,6 +828,17 @@ export class CliRenderer extends EventEmitter implements RenderContext {
   private selectionContainers: Renderable[] = []
   private clipboard: Clipboard
 
+  private lastClick: {
+    time: number
+    x: number
+    y: number
+    button: number
+    targetId: number
+    count: number
+  } | null = null
+
+  private readonly multiClickThresholdMs = 500
+
   private _splitHeight: number = 0
   private renderOffset: number = 0
   private splitTailColumn: number = 0
@@ -2708,7 +2719,11 @@ export class CliRenderer extends EventEmitter implements RenderContext {
 
   private flushPendingSplitOutputBeforeTransition(
     forceFooterRepaint: boolean = false,
-    options: { allowSuspended?: boolean; allowPassthrough?: boolean; allowUnsetup?: boolean } = {},
+    options: {
+      allowSuspended?: boolean
+      allowPassthrough?: boolean
+      allowUnsetup?: boolean
+    } = {},
   ): void {
     const hasDeferredCapturedOutput = this.externalOutputQueue.size > 0 || this.pendingExternalOutputMode !== null
     if (
@@ -3142,13 +3157,17 @@ export class CliRenderer extends EventEmitter implements RenderContext {
           return
         }
 
-        this.updateStdinParserProtocolContext({ startupCursorCprActive: false })
+        this.updateStdinParserProtocolContext({
+          startupCursorCprActive: false,
+        })
 
         if (this._screenMode === "split-footer" && this._externalOutputMode === "capture-stdout") {
           this.requestRender()
         }
 
-        this.flushPendingSplitOutputBeforeTransition(false, { allowPassthrough: true })
+        this.flushPendingSplitOutputBeforeTransition(false, {
+          allowPassthrough: true,
+        })
       }, 120)
     }
 
@@ -3403,6 +3422,35 @@ export class CliRenderer extends EventEmitter implements RenderContext {
     return event
   }
 
+  private getClickCount(mouseEvent: RawMouseEvent, targetId: number): number {
+    if (mouseEvent.type !== "down") return 0
+
+    const now = this.clock.now()
+    const previous = this.lastClick
+    // Treat a click as part of the same multi-click sequence only when it lands
+    // on the exact same cell and renderable; drags or nearby clicks start over.
+    const sameClickTarget =
+      previous &&
+      previous.button === mouseEvent.button &&
+      previous.targetId === targetId &&
+      previous.x === mouseEvent.x &&
+      previous.y === mouseEvent.y &&
+      now - previous.time <= this.multiClickThresholdMs
+
+    const count = sameClickTarget ? Math.min(previous.count + 1, 3) : 1
+
+    this.lastClick = {
+      time: now,
+      x: mouseEvent.x,
+      y: mouseEvent.y,
+      button: mouseEvent.button,
+      targetId,
+      count,
+    }
+
+    return count
+  }
+
   private processSingleMouseEvent(mouseEvent: RawMouseEvent): boolean {
     if (this._splitHeight > 0) {
       if (mouseEvent.y < this.renderOffset) {
@@ -3453,6 +3501,30 @@ export class CliRenderer extends EventEmitter implements RenderContext {
     this.lastOverRenderableNum = maybeRenderableId
     const maybeRenderable = Renderable.renderablesByNumber.get(maybeRenderableId)
 
+    if (
+      mouseEvent.type === "down" &&
+      mouseEvent.button === MouseButton.LEFT &&
+      maybeRenderable &&
+      maybeRenderable.selectable &&
+      !mouseEvent.modifiers.ctrl
+    ) {
+      const clickCount = this.getClickCount(mouseEvent, maybeRenderableId)
+
+      // Handle editor-specific multi-click selection before the normal
+      // single-click branch starts a drag selection at this same position.
+      if (clickCount === 2 && isEditBufferRenderable(maybeRenderable)) {
+        maybeRenderable.selectWordAt(mouseEvent.x, mouseEvent.y)
+        this.dispatchMouseEvent(maybeRenderable, mouseEvent)
+        return true
+      }
+
+      if (clickCount >= 3 && isEditBufferRenderable(maybeRenderable)) {
+        maybeRenderable.selectLineAt(mouseEvent.x, mouseEvent.y)
+        this.dispatchMouseEvent(maybeRenderable, mouseEvent)
+        return true
+      }
+    }
+
     if (
       mouseEvent.type === "down" &&
       mouseEvent.button === MouseButton.LEFT &&
@@ -3991,7 +4063,9 @@ export class CliRenderer extends EventEmitter implements RenderContext {
 
     if (this._terminalIsSetup) {
       this.clearSplitStartupCursorSeed()
-      this.flushPendingSplitOutputBeforeTransition(true, { allowSuspended: true })
+      this.flushPendingSplitOutputBeforeTransition(true, {
+        allowSuspended: true,
+      })
       this.suspendedNonAltSurfacePreserved = this._screenMode !== "alternate-screen" && this.renderOffset > 0
     } else {
       this.suspendedNonAltSurfacePreserved = false
@@ -4055,7 +4129,10 @@ export class CliRenderer extends EventEmitter implements RenderContext {
 
     this.suspendedNonAltSurfacePreserved = false
 
-    this.flushPendingSplitOutputBeforeTransition(false, { allowSuspended: true, allowPassthrough: true })
+    this.flushPendingSplitOutputBeforeTransition(false, {
+      allowSuspended: true,
+      allowPassthrough: true,
+    })
 
     if (this._screenMode === "split-footer" && this._splitHeight > 0) {
       this.syncSplitFooterState()
@@ -4199,7 +4276,10 @@ export class CliRenderer extends EventEmitter implements RenderContext {
     }
 
     if (this._feed !== null && this._splitHeight > 0 && !this._terminalIsSetup) {
-      this.flushPendingSplitOutputBeforeTransition(false, { allowSuspended: true, allowUnsetup: true })
+      this.flushPendingSplitOutputBeforeTransition(false, {
+        allowSuspended: true,
+        allowUnsetup: true,
+      })
     }
 
     this.externalOutputMode = "passthrough"