WIP: Start on CommandInterpreter and substitution

spec/atom/command-interpreter-spec.coffee

@@ -0,0 +1,18 @@
+CommandInterpreter = require 'command-interpreter'
+Buffer = require 'buffer'
+Editor = require 'editor'
+
+describe "CommandInterpreter", ->
+  [interpreter, editor, buffer] = []
+
+  beforeEach ->
+    buffer = new Buffer(require.resolve 'fixtures/sample.js')
+    editor = new Editor({buffer})
+    interpreter = new CommandInterpreter(editor)
+
+  describe "substitution", ->
+    fit "performs the substitution within the current dot", ->
+      editor.selection.setBufferRange([[6, 0], [6, 44]])
+      interpreter.eval('s/current/foo/')
+      expect(buffer.lineForRow(6)).toBe ' foo < pivot ? left.push(current) : right.push(current);'
+

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 +1,22 @@
+module.exports =
+class Substitution
+  constructor: (@findText, @replaceText) ->
+    @findRegex = new RegExp(@findText)
+
+  perform: (editor) ->
+    { buffer } = editor
+    selectedText = editor.getSelectedText()
+
+    # console.log editor.getSelection().getBufferRange()
+
+    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], @replace)
+

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)