From f1678fdafe9b2b6ac51b2909175dd36adb0e8f02 Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Wed, 20 Jun 2012 22:47:05 -0600
Subject: [PATCH] Use an overloaded 'tab' keybinding and the new
 `abortKeyBinding` method to implement conditional snippet expansion

If the current word prefix doesn't correspond to a valid snippet, we abort the key binding and try the next one, which ends up being the standard tab binding so a typical tab gets inserted. This is a mechanism that could support overloading of arbitrary keys.
---
 spec/extensions/snippets-spec.coffee    |  6 ++++--
 src/app/keymaps/snippets.coffee         |  6 ++++++
 src/extensions/snippets/snippets.coffee | 16 ++++++++--------
 3 files changed, 18 insertions(+), 10 deletions(-)
 create mode 100644 src/app/keymaps/snippets.coffee

diff --git a/spec/extensions/snippets-spec.coffee b/spec/extensions/snippets-spec.coffee
index 9db150add..499d88b95 100644
--- a/spec/extensions/snippets-spec.coffee
+++ b/spec/extensions/snippets-spec.coffee
@@ -13,6 +13,7 @@ describe "Snippets extension", ->
     editor = rootView.activeEditor()
     buffer = editor.buffer
     rootView.simulateDomAttachment()
+    rootView.enableKeymap()
 
   describe "when 'tab' is triggered on the editor", ->
     beforeEach ->
@@ -25,13 +26,14 @@ describe "Snippets extension", ->
         first go here:$1 then here:$2
         endsnippet
       """
+
     describe "when the letters preceding the cursor trigger a snippet", ->
       describe "when the snippet contains no tab stops", ->
         it "replaces the prefix with the snippet text and places the cursor at its end", ->
           editor.insertText("t1")
           expect(editor.getCursorScreenPosition()).toEqual [0, 2]
 
-          editor.trigger 'tab'
+          editor.trigger keydownEvent('tab', target: editor[0])
           expect(buffer.lineForRow(0)).toBe "this is a testvar quicksort = function () {"
           expect(editor.getCursorScreenPosition()).toEqual [0, 14]
 
@@ -59,7 +61,7 @@ describe "Snippets extension", ->
       expect(fs.read).toHaveBeenCalledWith('/tmp/foo/js.snippets')
 
       editor.insertText("t1")
-      editor.trigger 'tab'
+      editor.trigger 'snippets:expand'
       expect(buffer.lineForRow(0)).toBe "this is a test 1var quicksort = function () {"
 
   describe "Snippets parser", ->
diff --git a/src/app/keymaps/snippets.coffee b/src/app/keymaps/snippets.coffee
new file mode 100644
index 000000000..6227dd8c1
--- /dev/null
+++ b/src/app/keymaps/snippets.coffee
@@ -0,0 +1,6 @@
+window.keymap.bindKeys '.editor'
+  'tab': 'snippets:expand'
+
+window.keymap.bindKeys '.editor'
+  'tab': 'snippets:next-tab-stop'
+  'shift-tab': 'snippets:previous-tab-stop'
diff --git a/src/extensions/snippets/snippets.coffee b/src/extensions/snippets/snippets.coffee
index 9e3517d00..d69a8c00d 100644
--- a/src/extensions/snippets/snippets.coffee
+++ b/src/extensions/snippets/snippets.coffee
@@ -9,12 +9,7 @@ module.exports =
 
   activate: (@rootView) ->
     @loadSnippets()
-
-    for editor in @rootView.editors()
-      @enableSnippetsInEditor(editor)
-
-    @rootView.on 'editor-open', (e, editor) =>
-      @enableSnippetsInEditor(editor)
+    @rootView.on 'editor-open', (e, editor) => @enableSnippetsInEditor(editor)
 
   loadSnippets: ->
     snippetsDir = fs.join(atom.configDirPath, 'snippets')
@@ -28,10 +23,13 @@ module.exports =
     @snippetsByExtension[extension] = @snippetsParser.parse(text)
 
   enableSnippetsInEditor: (editor) ->
-    editor.preempt 'tab', =>
+    editor.on 'snippets:expand', (e) =>
       editSession = editor.activeEditSession
       editSession.snippetsSession ?= new SnippetsSession(editSession, @snippetsByExtension)
-      editSession.snippetsSession.expandSnippet()
+      e.abortKeyBinding() unless editSession.snippetsSession.expandSnippet()
+
+    # this is currently disabled. soon we will jump tab stops if a snippet is active
+    editor.on 'snippets:next-tab-stop', (e) -> e.abortKeyBinding()
 
 class SnippetsSession
   constructor: (@editSession, @snippetsByExtension) ->
@@ -42,4 +40,6 @@ class SnippetsSession
     if body = snippets[prefix]?.body
       @editSession.selectToBeginningOfWord()
       @editSession.insertText(body)
+      true
+    else
       false