[sass mode] Improve indentation

Fixes bug #2156 for the most part

indention was bugged because it was reaching a wrong state when
any text that was not in the known set of words or patterns was
incurred.

for eg:
	head
		| <---- cursor should be here

and lets take  color : red as another example
now 'red' is same to the current tokenizer as 'head' from the first
example. So it indents for red automatically.

It was fixed by not letting any text after colon to reach the state
where it appends an indent after it.

mode/sass/sass.js

@@ -22,7 +22,7 @@ CodeMirror.defineMode("sass", function(config) {
   var operators = ["\\(", "\\)", "=", ">", "<", "==", ">=", "<=", "\\+", "-", "\\!=", "/", "\\*", "%", "and", "or", "not"];
   var opRegexp = tokenRegexp(operators);
 
-  var pseudoElementsRegexp = /^::?[\w\-]+/;
+  var pseudoElementsRegexp = /^::[\w\-]+/;
 
   function urlTokens(stream, state) {
     var ch = stream.peek();
@@ -64,7 +64,7 @@ CodeMirror.defineMode("sass", function(config) {
   }
 
   function buildStringTokenizer(quote, greedy) {
-    if(greedy == null) { greedy = true; }
+    if (greedy == null) { greedy = true; }
 
     function stringTokenizer(stream, state) {
       var nextChar = stream.next();
@@ -189,13 +189,11 @@ CodeMirror.defineMode("sass", function(config) {
     if (ch === "$") {
       stream.next();
       stream.eatWhile(/[\w-]/);
-
-      if (stream.peek() === ":") {
-        stream.next();
+      stream.eatSpace();
+      if (stream.peek() === ":")
         return "variable-2";
-      } else {
+      else
         return "variable-3";
-      }
     }
 
     if (ch === "!") {
@@ -245,22 +243,71 @@ CodeMirror.defineMode("sass", function(config) {
       return "string";
     }
 
-    // Pseudo element selectors
-    if (ch == ":" && stream.match(pseudoElementsRegexp))
-      return "keyword";
+    // Pseudo element selectors and values after colon
+    if (ch === ":"){
+      if (stream.match(pseudoElementsRegexp))
+        return "keyword";
+      stream.next();
+      stream.eatSpace();
+      if (stream.peek() === null){
+        // if there is no more space after it
+        indent(state);
+        return "atom";
+      }
 
-    // atoms
-    if (stream.eatWhile(/[\w-&]/)) {
-      // matches a property definition
-      if (stream.peek() === ":" && !stream.match(pseudoElementsRegexp, false))
-        return "property";
-      else
+      // all posible tokens after colon
+      if (stream.match(/\$[\w-]+/)){
+        // variables
+        return "variable-3";
+      } else if (stream.match(/^url/) && stream.peek() === "(") {
+        //urls
+        state.tokenizer = urlTokens;
+        return "atom";
+      } else if (stream.match(/#[0-9a-fA-F]{6}|#[0-9a-fA-F]{3}/)){
+        //hexadecimal value
+        return "number";
+      } else if (stream.match(/^-?[0-9\.]+/)){
+        return "number";
+      } else if (stream.match(keywordsRegexp)){
+        return "keyword";
+      } else if (stream.match(/[\w-,\s]+/)){
+        // other text
         return "atom";
+      }
     }
 
     if (stream.match(opRegexp))
       return "operator";
 
+    // atoms
+    if (stream.eatWhile(/[\w-&]/)) {
+      stream.eatSpace();
+      // matches a property definition
+      if (stream.peek() === ":" ){
+        if (!stream.match(/:[ ]*[\d\w-\$\+#!\("']/,false)){
+         //for cases where line ends after colon
+         // eg
+         // font:
+         //   | <-----cursor
+          indent(state);
+          return "property";
+        } else if (!stream.match(pseudoElementsRegexp, false)){
+          return "property";
+        }
+      } else {
+        stream.eatSpace();
+        if (stream.peek() !== "," ){
+          //for cases where line ends after comma
+          //eg
+          //head,
+          //body,
+          //| <-----cursor
+          indent(state);
+        }
+        return "atom";
+      }
+    }
+
     // If we haven't returned by now, we move 1 character
     // and return an error
     stream.next();
@@ -275,9 +322,6 @@ CodeMirror.defineMode("sass", function(config) {
     if (current === "@return")
       dedent(state);
 
-    if (style === "atom")
-      indent(state);
-
     if (style !== null) {
       var startOfToken = stream.pos - current.length;
       var withCurrentIndent = startOfToken + (config.indentUnit * state.indentCount);