Snippets can contain placeholder text (but can't nest yet)

Snippet placeholders are managed by adding an "anchor range" to the edit session. An anchor range basically tracks two anchors for the start and the end of the range.

spec/extensions/snippets-spec.coffee

@@ -33,6 +33,11 @@ describe "Snippets extension", ->
           line 2$1
 
         endsnippet
+
+        snippet t4 "With tab stop placeholders"
+        go here ${1:first} and then here ${2:second}
+
+        endsnippet
       """
 
     describe "when the letters preceding the cursor trigger a snippet", ->
@@ -81,6 +86,13 @@ describe "Snippets extension", ->
           expect(buffer.lineForRow(2)).toBe "go here next:(abc) and finally go here:(  )"
           expect(editor.activeEditSession.getAnchors().length).toBe anchorCountBefore
 
+        describe "when the tab stops have placeholder text", ->
+          it "auto-fills the placeholder text and highlights it when navigating to that tab stop", ->
+            editor.insertText 't4'
+            editor.trigger 'snippets:expand'
+            expect(buffer.lineForRow(0)).toBe 'go here first and then here second'
+            expect(editor.getSelectedBufferRange()).toEqual [[0, 8], [0, 13]]
+
       describe "when a the start of the snippet is indented", ->
         it "indents the subsequent lines of the snippet to be even with the start of the first line", ->
           editor.setCursorScreenPosition([2, Infinity])
@@ -151,4 +163,4 @@ describe "Snippets extension", ->
         go here first:()
       """
 
-      expect(snippet.tabStops).toEqual [[1, 15], [0, 14], [0, 37]]
+      expect(snippet.tabStops).toEqual [[[1, 15], [1, 15]], [[0, 14], [0, 14]], [[0, 37], [0, 37]]]