Moving the cursor without holding shift clears selection

spec/atom/editor-spec.coffee

@@ -1,5 +1,6 @@
 Buffer = require 'buffer'
 Editor = require 'editor'
+Range = require 'range'
 $ = require 'jquery'
 _ = require 'underscore'
 fs = require 'fs'
@@ -218,7 +219,7 @@ describe "Editor", ->
 
             expect(editor.getCursorPosition()).toEqual(lastPosition)
 
-  describe "selection creation", ->
+  describe "selection bindings", ->
     selection = null
 
     beforeEach ->
@@ -242,6 +243,43 @@ describe "Editor", ->
         expect(range.start).toEqual(row: 1, column: 6)
         expect(range.end).toEqual(row: 1, column: 8)
 
+        editor.trigger keydownEvent('down', shiftKey: true)
+        range = selection.getRange()
+        expect(range.start).toEqual(row: 1, column: 6)
+        expect(range.end).toEqual(row: 2, column: 8)
+
+        editor.trigger keydownEvent('left', shiftKey: true)
+        range = selection.getRange()
+        expect(range.start).toEqual(row: 1, column: 6)
+        expect(range.end).toEqual(row: 2, column: 7)
+
+        editor.trigger keydownEvent('up', shiftKey: true)
+        range = selection.getRange()
+        expect(range.start).toEqual(row: 1, column: 6)
+        expect(range.end).toEqual(row: 1, column: 7)
+
+    describe "when the arrow keys are pressed without the shift modifier", ->
+      makeNonEmpty = ->
+        selection.setRange(new Range({row: 1, column: 2}, {row: 1, column: 5}))
+        expect(selection.isEmpty()).toBeFalsy()
+
+      it "clears the selection", ->
+        makeNonEmpty()
+        editor.trigger keydownEvent('right')
+        expect(selection.isEmpty()).toBeTruthy()
+
+        makeNonEmpty()
+        editor.trigger keydownEvent('left')
+        expect(selection.isEmpty()).toBeTruthy()
+
+        makeNonEmpty()
+        editor.trigger keydownEvent('up')
+        expect(selection.isEmpty()).toBeTruthy()
+
+        makeNonEmpty()
+        editor.trigger keydownEvent('down')
+        expect(selection.isEmpty()).toBeTruthy()
+
 
   describe "when text input events are triggered on the hidden input element", ->
     it "inserts the typed character at the cursor position, both in the buffer and the pre element", ->

spec/atom/selection-spec.coffee

@@ -19,7 +19,7 @@ describe "Selection", ->
       expect(selection.anchor.getPosition()).toEqual range.start
       expect(selection.cursor.getPosition()).toEqual range.end
 
-  fdescribe ".updateAppearence()", ->
+  describe ".updateAppearence()", ->
     [charWidth, lineHeight] = []
 
     beforeEach ->

src/atom/buffer.coffee

@@ -1,5 +1,4 @@
 fs = require 'fs'
-{Document} = require 'ace/document'
 
 module.exports =
 class Buffer
@@ -70,10 +69,10 @@ class Buffer
     fs.write @path, @getText()
 
   on: (eventName, handler) ->
-    @handlers ?= {}
-    @handlers[eventName] ?= []
-    @handlers[eventName].push(handler)
+    @eventHandlers ?= {}
+    @eventHandlers[eventName] ?= []
+    @eventHandlers[eventName].push(handler)
 
-  trigger: (eventName, data) ->
-    @handlers?[eventName]?.forEach (handler) -> handler(data)
+  trigger: (eventName, event) ->
+    @eventHandlers?[eventName]?.forEach (handler) -> handler(event)
 

src/atom/cursor.coffee

@@ -21,6 +21,7 @@ class Cursor extends Template
       @point = @editor.clipPosition(point)
       @goalColumn = null
       @selection.updateAppearance()
+      @trigger 'cursor:position-changed'
 
     getPosition: -> _.clone(@point)
 

src/atom/editor.coffee

@@ -33,6 +33,9 @@ class Editor extends Template
         down: 'move-down'
         up: 'move-up'
         'shift-right': 'select-right'
+        'shift-left': 'select-left'
+        'shift-up': 'select-up'
+        'shift-down': 'select-down'
         enter: 'newline'
         backspace: 'backspace'
 
@@ -41,6 +44,9 @@ class Editor extends Template
       @on 'move-down', => @moveCursorDown()
       @on 'move-up', => @moveCursorUp()
       @on 'select-right', => @selectRight()
+      @on 'select-left', => @selectLeft()
+      @on 'select-up', => @selectUp()
+      @on 'select-down', => @selectDown()
       @on 'newline', =>  @insertNewline()
       @on 'backspace', => @backspace()
 
@@ -137,6 +143,9 @@ class Editor extends Template
     getCursorColumn: -> @selection.getCursorColumn()
 
     selectRight: -> @selection.selectRight()
+    selectLeft: -> @selection.selectLeft()
+    selectUp: -> @selection.selectUp()
+    selectDown: -> @selection.selectDown()
 
     insertText: (text) -> @selection.insertText(text)
     insertNewline: -> @selection.insertNewline()

src/atom/selection.coffee

@@ -9,12 +9,20 @@ class Selection extends Template
     @div()
 
   viewProperties:
+    anchor: null
+    modifyingSelection: null
     regions: null
 
     initialize: (editor) ->
       @editor = editor
-      @cursor = Cursor.build(this).appendTo(this)
       @regions = []
+      @cursor = Cursor.build(this).appendTo(this)
+      @cursor.on 'cursor:position-changed', =>
+        @clearSelection() unless @modifyingSelection
+
+    clearSelection: ->
+      @anchor = null
+      @updateAppearance()
 
     bufferChanged: (e) ->
       @cursor.setPosition(e.postRange.end)
@@ -58,10 +66,16 @@ class Selection extends Template
       region.remove() for region in @regions
       @regions = []
 
+    getRange: ->
+      if @anchor
+        new Range(@anchor.getPosition(), @cursor.getPosition())
+      else
+        new Range(@cursor.getPosition(), @cursor.getPosition())
+
     setRange: (range) ->
       @cursor.setPosition(range.start)
-      @placeAnchor()
-      @cursor.setPosition(range.end)
+      @modifySelection =>
+        @cursor.setPosition(range.end)
 
     insertText: (text) ->
       @editor.buffer.change(@getRange(), text)
@@ -84,11 +98,11 @@ class Selection extends Template
     isEmpty: ->
       @getRange().isEmpty()
 
-    getRange: ->
-      if @anchor
-        new Range(@anchor.getPosition(), @cursor.getPosition())
-      else
-        new Range(@cursor.getPosition(), @cursor.getPosition())
+    modifySelection: (fn) ->
+      @placeAnchor()
+      @modifyingSelection = true
+      fn()
+      @modifyingSelection = false
 
     placeAnchor: ->
       return if @anchor
@@ -126,8 +140,20 @@ class Selection extends Template
       @cursor.moveRight()
 
     selectRight: ->
-      @placeAnchor()
-      @cursor.moveRight()
+      @modifySelection =>
+        @cursor.moveRight()
+
+    selectLeft: ->
+      @modifySelection =>
+        @cursor.moveLeft()
+
+    selectUp: ->
+      @modifySelection =>
+        @cursor.moveUp()
+
+    selectDown: ->
+      @modifySelection =>
+        @cursor.moveDown()
 
     moveCursorToLineEnd: ->
       @cursor.moveToLineEnd()