Add moveToPreviousWordBoundry to cursor.

Plumb it up to a command in the editor.

spec/app/edit-session-spec.coffee

@@ -313,6 +313,21 @@ describe "EditSession", ->
         editSession.moveCursorToBeginningOfWord()
         expect(editSession.getCursorBufferPosition()).toEqual [9, 2]
 
+    fdescribe ".moveCursorToPreviousWordBoundry()", ->
+      it "moves the cursor to the previous word boundry", ->
+        editSession.setCursorBufferPosition [0, 8]
+        editSession.addCursorAtBufferPosition [2, 0]
+        editSession.addCursorAtBufferPosition [2, 4]
+        editSession.addCursorAtBufferPosition [3, 14]
+        [cursor1, cursor2, cursor3, cursor4] = editSession.getCursors()
+
+        editSession.moveCursorToPreviousWordBoundry()
+
+        expect(cursor1.getBufferPosition()).toEqual [0, 4]
+        expect(cursor2.getBufferPosition()).toEqual [1, 30]
+        expect(cursor3.getBufferPosition()).toEqual [2, 0]
+        expect(cursor4.getBufferPosition()).toEqual [3, 13]
+
     describe ".moveCursorToEndOfWord()", ->
       it "moves the cursor to the end of the word", ->
         editSession.setCursorBufferPosition [0, 6]

src/app/cursor.coffee

@@ -244,6 +244,11 @@ class Cursor
     if position = @getBeginningOfNextWordBufferPosition()
       @setBufferPosition(position)
 
+  # Moves the cursor to the previous word boundry.
+  moveToPreviousWordBoundry: ->
+    if position = @getMovePreviousWordBoundryBufferPosition()
+      @setBufferPosition(position)
+
   # Retrieves the buffer position of where the current word starts.
   #
   # options - A hash with one option:
@@ -265,6 +270,28 @@ class Cursor
 
     beginningOfWordPosition or currentBufferPosition
 
+  # Retrieves buffer position of previous word boiundry. It might be on the
+  # current word, or the previous word.
+  getMovePreviousWordBoundryBufferPosition: (options = {}) ->
+    currentBufferPosition = @getBufferPosition()
+    previousNonBlankRow = @editSession.buffer.previousNonBlankRow(currentBufferPosition.row)
+    scanRange = [[previousNonBlankRow, 0], currentBufferPosition]
+
+    beginningOfWordPosition = null
+    @editSession.backwardsScanInBufferRange (options.wordRegex ? @wordRegExp()), scanRange, ({range, stop}) =>
+      if range.start.row < currentBufferPosition.row and currentBufferPosition.column > 0
+        # force it to stop at the beginning of each line
+        beginningOfWordPosition = new Point(currentBufferPosition.row, 0)
+      else if range.end.isLessThan(currentBufferPosition)
+        beginningOfWordPosition = range.end
+      else
+        beginningOfWordPosition = range.start
+
+      if not beginningOfWordPosition?.isEqual(currentBufferPosition)
+        stop()
+
+    beginningOfWordPosition or currentBufferPosition
+
   # Retrieves the buffer position of where the current word ends.
   #
   # options - A hash with one option:

src/app/edit-session.coffee

@@ -1101,6 +1101,9 @@ class EditSession
   moveCursorToBeginningOfNextWord: ->
     @moveCursors (cursor) -> cursor.moveToBeginningOfNextWord()
 
+  moveCursorToPreviousWordBoundry: ->
+    @moveCursors (cursor) -> cursor.moveToPreviousWordBoundry()
+
   # Internal:
   moveCursors: (fn) ->
     fn(cursor) for cursor in @getCursors()

src/app/editor.coffee

@@ -141,6 +141,7 @@ class Editor extends View
       'editor:move-to-beginning-of-word': @moveCursorToBeginningOfWord
       'editor:move-to-end-of-word': @moveCursorToEndOfWord
       'editor:move-to-beginning-of-next-word': @moveCursorToBeginningOfNextWord
+      'editor:move-to-previous-word-boundry': @moveCursorToPreviousWordBoundry
       'editor:select-to-end-of-line': @selectToEndOfLine
       'editor:select-to-beginning-of-line': @selectToBeginningOfLine
       'editor:select-to-end-of-word': @selectToEndOfWord
@@ -237,6 +238,9 @@ class Editor extends View
   # {Delegates to: EditSession.moveCursorToFirstCharacterOfLine}
   moveCursorToFirstCharacterOfLine: -> @activeEditSession.moveCursorToFirstCharacterOfLine()
 
+  # {Delegates to: EditSession.moveCursorToPreviousWordBoundry}
+  moveCursorToPreviousWordBoundry: -> @activeEditSession.moveCursorToPreviousWordBoundry()
+
   # {Delegates to: EditSession.moveCursorToEndOfLine}
   moveCursorToEndOfLine: -> @activeEditSession.moveCursorToEndOfLine()