Typing inserts a character at the cursor position

src/atom/buffer.coffee

@@ -24,6 +24,18 @@ class Buffer
   getLine: (n) ->
     @lines[n]
 
+  insert: ({row, col}, string) ->
+    line = @getLine(row)
+    before = line.substring(0, col)
+    after = line.substring(col)
+    @lines[row] = before + string + after
+
+    @trigger 'insert'
+      string: string
+      range:
+        start: {row, col}
+        end: {row, col}
+
   numLines: ->
     @getLines().length
 
@@ -31,3 +43,11 @@ class Buffer
     if not @path then throw new Error("Tried to save buffer with no url")
     fs.write @path, @getText()
 
+  on: (eventName, handler) ->
+    @handlers ?= {}
+    @handlers[eventName] ?= []
+    @handlers[eventName].push(handler)
+
+  trigger: (eventName, data) ->
+    @handlers?[eventName]?.forEach (handler) -> handler(data)
+

src/atom/cursor.coffee

@@ -6,6 +6,10 @@ class Cursor extends Template
     @pre class: 'cursor', style: 'position: absolute;', => @raw ' '
 
   viewProperties:
+    setBuffer: (@buffer) ->
+      @buffer.on 'insert', (e) =>
+        @setColumn(@getColumn() + e.string.length)
+
     setPosition: (point) ->
       @point = @parentView.clipPosition(point)
       @goalColumn = null
@@ -17,6 +21,9 @@ class Cursor extends Template
       { row } = @getPosition()
       @setPosition {row, col}
 
+    getColumn: ->
+      @getPosition().col
+
     moveUp: ->
       { row, col } = @getPosition()
       col = @goalColumn if @goalColumn?

src/atom/editor.coffee

@@ -36,6 +36,9 @@ class Editor extends Template
         @hiddenInput.focus()
         false
 
+      @hiddenInput.on "textInput", (e) =>
+        @buffer.insert(@getPosition(), e.originalEvent.data)
+
       @one 'attach', =>
         @calculateDimensions()
 
@@ -47,6 +50,10 @@ class Editor extends Template
         else
           @lines.append $$.pre(line)
       @setPosition(row: 0, col: 0)
+      @cursor.setBuffer(@buffer)
+      @buffer.on 'insert', (e) =>
+        {row} = e.range.start
+        @lines.find('pre').eq(row).replaceWith $$.pre(@buffer.getLine(row))
 
     clipPosition: ({row, col}) ->
       line = @buffer.getLine(row)
@@ -69,6 +76,8 @@ class Editor extends Template
       else
         @scrollTop() + @height()
 
+    getCurrentLine: -> @buffer.getLine(@getPosition().row)
+
     moveUp: -> @cursor.moveUp()
     moveDown: -> @cursor.moveDown()
     moveRight: -> @cursor.moveRight()