Implement dw (delete to beginning of next word)

The w motion has a .select() method. When d composes with a motion it
calls select() on it and then deletes the selected text.

src/atom/editor.coffee

@@ -58,6 +58,14 @@ class Editor extends Template
     setCursor: ({column, row}) ->
       @aceEditor.navigateTo(row, column)
 
+    selectToPosition: (position) ->
+      { row, column } = @getCursor()
+      @aceEditor.selection.setSelectionAnchor(row, column)
+      @aceEditor.moveCursorToPosition(position)
+
+    delete: ->
+      @getAceSession().remove(@aceEditor.getSelectionRange())
+
     getCursor: ->
       @getAceSession().getSelection().getCursor()
 

src/atom/vim-mode-operators.coffee

@@ -24,9 +24,18 @@ module.exports =
 
   Delete: class
     complete: null
+    motion: null
 
     execute: (editor) ->
-      editor.deleteLine()
+      if @motion
+        @motion.select(editor)
+        editor.delete()
+      else
+        editor.deleteLine()
+
+    compose: (motion) ->
+      @motion = motion
+      @complete = true
 
     isComplete: -> @complete
 
@@ -51,7 +60,15 @@ module.exports =
     isComplete: -> true
 
   MoveToNextWord: class
+    isComplete: -> true
+
     execute: (editor) ->
+      editor.setCursor(@nextWordPosition(editor))
+
+    select: (editor) ->
+      editor.selectToPosition(@nextWordPosition(editor))
+
+    nextWordPosition: (editor) ->
       regex = getWordRegex()
       { row, column } = editor.getCursor()
       rightOfCursor = editor.getLineText(row).substring(column)
@@ -65,8 +82,6 @@ module.exports =
       else
         nextLineMatch = regex.exec(editor.getLineText(++row))
         column = nextLineMatch?.index or 0
+      { row, column }
 
-      editor.setCursor { row, column }
-
-    isComplete: -> true