Merge branch 'sam'

src/atom/buffer.coffee

@@ -1,5 +1,6 @@
 _ = require 'underscore'
 fs = require 'fs'
+Point = require 'point'
 Range = require 'range'
 EventEmitter = require 'event-emitter'
 UndoManager = require 'undo-manager'
@@ -59,6 +60,21 @@ class Buffer
   lastLine: ->
     @lineForRow(@lastRow())
 
+  characterIndexForPosition: (position) ->
+    position = Point.fromObject(position)
+
+    index = 0
+    index += @getLineLength(row) + 1 for row in [0...position.row]
+    index + position.column
+
+  positionForCharacterIndex: (index) ->
+    row = 0
+    while index >= (lineLength = @getLineLength(row) + 1)
+      index -= lineLength
+      row++
+
+    new Point(row, index)
+
   deleteRow: (row) ->
     range = null
     if row == @lastRow()

src/atom/command-interpreter.coffee

@@ -0,0 +1,12 @@
+fs = require 'fs'
+PEG = require 'pegjs'
+
+module.exports =
+class CommandInterpreter
+  constructor: (@editor) ->
+    @parser = PEG.buildParser(fs.read(require.resolve 'commands.pegjs'))
+
+  eval: (command) ->
+    operation = @parser.parse(command)
+    operation.perform(@editor)
+

src/atom/command-interpreter/substitution.coffee

@@ -0,0 +1,20 @@
+module.exports =
+class Substitution
+  constructor: (@findText, @replaceText) ->
+    @findRegex = new RegExp(@findText)
+
+  perform: (editor) ->
+    { buffer } = editor
+    selectedText = editor.getSelectedText()
+
+    selectionStartIndex = buffer.characterIndexForPosition(editor.getSelection().getBufferRange().start)
+
+    match = @findRegex.exec(selectedText)
+    matchStartIndex = selectionStartIndex + match.index
+    matchEndIndex = matchStartIndex + match[0].length
+
+    startPosition = buffer.positionForCharacterIndex(matchStartIndex)
+    endPosition = buffer.positionForCharacterIndex(matchEndIndex)
+
+    buffer.change([startPosition, endPosition], @replaceText)
+

src/atom/commands.pegjs

@@ -0,0 +1,8 @@
+{
+  var Substitution = require('command-interpreter/substitution');
+}
+
+substitution
+  = "s" _ "/" find:([^/]*) "/" replace:([^/]*) "/" { return new Substitution(find.join(''), replace.join('')) }
+
+_ = " "*

src/atom/line-map.coffee

@@ -61,6 +61,7 @@ class LineMap
     @translatePosition('screenDelta', 'bufferDelta', screenPosition)
 
   screenRangeForBufferRange: (bufferRange) ->
+    bufferRange = Range.fromObject(bufferRange)
     start = @screenPositionForBufferPosition(bufferRange.start)
     end = @screenPositionForBufferPosition(bufferRange.end)
     new Range(start, end)