Expansion of nested snippets

lib/snippet-expansion.coffee

@@ -53,7 +53,14 @@ class SnippetExpansion
       false
 
   goToPreviousTabStop: ->
-    @setTabStopIndex(@tabStopIndex - 1) if @tabStopIndex > 0
+    if @tabStopIndex > 0
+      if @setTabStopIndex(@tabStopIndex - 1)
+        true
+      else
+        @goToPreviousTabStop()
+    else
+      @destroy()
+      false
 
   setTabStopIndex: (@tabStopIndex) ->
     @settingTabStop = true
@@ -84,7 +91,7 @@ class SnippetExpansion
     for markers in @tabStopMarkers
       marker.destroy() for marker in markers
     @tabStopMarkers = []
-    @snippets.clearExpansions(@editor)
+    @snippets.clearCurrentExpansions(@editor)
 
   restore: (@editor) ->
     @snippets.addExpansion(@editor, this)

lib/snippets.coffee

@@ -32,7 +32,7 @@ module.exports =
       'snippets:expand': (event) ->
         editor = @getModel()
         if snippets.snippetToExpandUnderCursor(editor)
-          snippets.clearExpansions(editor)
+          snippets.newCurrentExpansions(editor)
           snippets.expandSnippetsUnderCursors(editor)
         else
           event.abortKeyBinding()
@@ -306,27 +306,45 @@ module.exports =
 
   goToNextTabStop: (editor) ->
     nextTabStopVisited = false
-    for expansion in @getExpansions(editor)
-      if expansion?.goToNextTabStop()
-        nextTabStopVisited = true
+    while currentExpansions = @getCurrentExpansions(editor)
+      @clearCurrentExpansions(editor) unless currentExpansions.length
+      for expansion in currentExpansions
+        if expansion?.goToNextTabStop()
+          nextTabStopVisited = true
+      break if nextTabStopVisited
     nextTabStopVisited
 
   goToPreviousTabStop: (editor) ->
     previousTabStopVisited = false
-    for expansion in @getExpansions(editor)
-      if expansion?.goToPreviousTabStop()
-        previousTabStopVisited = true
+    while currentExpansions = @getCurrentExpansions(editor)
+      @clearCurrentExpansions(editor) unless currentExpansions.length
+      for expansion in currentExpansions
+        if expansion?.goToPreviousTabStop()
+          previousTabStopVisited = true
+      break if previousTabStopVisited
     previousTabStopVisited
 
   getExpansions: (editor) ->
-    @editorSnippetExpansions?.get(editor) ? []
+    @editorSnippetExpansions.get(editor)
+
+  getCurrentExpansions: (editor) ->
+    expansions = @getExpansions(editor)
+    return expansions[expansions.length - 1] if expansions.length
 
   clearExpansions: (editor) ->
     @editorSnippetExpansions ?= new WeakMap()
     @editorSnippetExpansions.set(editor, [])
 
+  clearCurrentExpansions: (editor) ->
+    expansions = @getExpansions(editor)
+    expansions.pop() if expansions.length
+
   addExpansion: (editor, snippetExpansion) ->
-    @getExpansions(editor).push(snippetExpansion)
+    if not @getCurrentExpansions(editor)?.push(snippetExpansion)
+      @getExpansions(editor).push([snippetExpansion])
+
+  newCurrentExpansions: (editor) ->
+    @getExpansions(editor).push([])
 
   insert: (snippet, editor=atom.workspace.getActiveTextEditor(), cursor=editor.getLastCursor()) ->
     if typeof snippet is 'string'

spec/snippets-spec.coffee

@@ -267,10 +267,6 @@ describe "Snippets extension", ->
           simulateTabKeyEvent(shift: true)
           expect(editor.getSelectedBufferRange()).toEqual [[3, 15], [3, 15]]
 
-          # shift-tab on first tab-stop does nothing
-          simulateTabKeyEvent(shift: true)
-          expect(editor.getCursorScreenPosition()).toEqual [3, 15]
-
           # tab through all tab stops, then tab on last stop to terminate snippet
           simulateTabKeyEvent()
           simulateTabKeyEvent()
@@ -655,6 +651,43 @@ describe "Snippets extension", ->
           expect(editor.lineTextForBufferRow(7)).toBe "    }one t1 three"
           expect(editor.lineTextForBufferRow(12)).toBe "};one t1 three"
 
+    describe "when there are nested snippets", ->
+      it "tries to expand before moving to the next tabstop", ->
+        spyOn(Snippets, 'snippetToExpandUnderCursor').andReturn(false)
+        spyOn(Snippets, 'goToNextTabStop').andReturn(true)
+
+        simulateTabKeyEvent()
+        expect(Snippets.snippetToExpandUnderCursor).toHaveBeenCalled()
+        expect(Snippets.goToNextTabStop).toHaveBeenCalled()
+
+      it "moves to surrounding expansions after terminating a snippet", ->
+        editor.setText 't2'
+        editor.setCursorScreenPosition [0, 2]
+        simulateTabKeyEvent()
+        editor.insertText 't2'
+        simulateTabKeyEvent()
+        expect(editor.lineTextForBufferRow(0)).toBe "go here next:() and finally go here:()"
+        expect(editor.lineTextForBufferRow(1)).toBe "go here first:(go here next:() and finally go here:()"
+        expect(editor.lineTextForBufferRow(2)).toBe "go here first:())"
+        expect(editor.getSelectedBufferRange()).toEqual [[2, 15], [2, 15]]
+
+        simulateTabKeyEvent()
+        simulateTabKeyEvent()
+        editor.insertText 't5'
+        simulateTabKeyEvent()
+        simulateTabKeyEvent(shift: true)
+        expect(editor.lineTextForBufferRow(1)).toBe 'go here first:(go here next:() and finally go here:("key": value)'
+        expect(editor.getSelectedBufferRange()).toEqual [[1, 29], [1, 29]]
+
+        simulateTabKeyEvent()
+        simulateTabKeyEvent()
+        expect(editor.lineTextForBufferRow(0)).toBe "go here next:() and finally go here:()"
+        expect(editor.getSelectedBufferRange()).toEqual [[0, 14], [0, 14]]
+
+        simulateTabKeyEvent()
+        simulateTabKeyEvent()
+        expect(editor.lineTextForBufferRow(0)).toBe "go here next:() and finally go here:(  )"
+
   describe "when atom://.atom/snippets is opened", ->
     it "opens ~/.atom/snippets.cson", ->
       jasmine.unspy(Snippets, 'getUserSnippetsPath')