correcting broken fix for #2333 regarding string escape sequences

Sorry for all the commits! It should really be done this time.

lib/coffee-script/nodes.js

@@ -1172,16 +1172,34 @@
     Obj.prototype.children = ['properties'];
 
     Obj.prototype.compileNode = function(o) {
-      var i, idt, indent, isDuplicate, join, lastNoncom, node, normalise, obj, prop, propName, propNames, props, _i, _j, _len, _len1, _ref2;
+      var i, idt, indent, isDuplicate, join, lastNoncom, node, normaliseString, obj, prop, propName, propNames, props, _i, _j, _len, _len1, _ref2;
       props = this.properties;
       propNames = [];
-      normalise = function(s) {
-        switch (s[0]) {
-          case '"':
-            return s.slice(1, -1).replace(/\\"/g, '"');
-          case "'":
-            return s.slice(1, -1).replace(/\\'/g, "'");
-        }
+      normaliseString = function(s) {
+        var octalNormalised, quoteNormalised;
+        quoteNormalised = (function() {
+          switch (s[0]) {
+            case '"':
+              return s.slice(1, -1).replace(/\\"/g, '"');
+            case "'":
+              return s.slice(1, -1).replace(/\\'/g, "'");
+          }
+        })();
+        octalNormalised = quoteNormalised.replace(/\\([0btnvfr\\])/, function(match, c) {
+          return {
+            0: "\0",
+            b: "\b",
+            t: "\t",
+            n: "\n",
+            v: "\v",
+            f: "\f",
+            r: "\r",
+            "\\": "\\"
+          }[c];
+        });
+        return octalNormalised.replace(/\\x([0-9a-f]{2})|\\u([0-9a-f]{4})/i, function(match, h, u) {
+          return String.fromCharCode(parseInt(h != null ? h : u, 16));
+        });
       };
       isDuplicate = function(x) {
         var mx;
@@ -1193,15 +1211,15 @@
           }
           my = y.match(/^['"]/);
           if (mx && my) {
-            if (normalise(x) === normalise(y)) {
+            if (normaliseString(x) === normaliseString(y)) {
               return true;
             }
           } else if (mx) {
-            if (y === x.slice(1, -1)) {
+            if (y === normaliseString(x)) {
               return true;
             }
           } else if (my) {
-            if (x === y.slice(1, -1)) {
+            if (x === normaliseString(y)) {
               return true;
             }
           }

src/nodes.coffee

@@ -802,20 +802,25 @@ exports.Obj = class Obj extends Base
   compileNode: (o) ->
     props = @properties
     propNames = []
-    normalise = (s) -> switch s[0]
-      when '"' then s[1...-1].replace /\\"/g, '"'
-      when "'" then s[1...-1].replace /\\'/g, "'"
+    normaliseString = (s) ->
+      quoteNormalised = switch s[0]
+        when '"' then s[1...-1].replace /\\"/g, '"'
+        when "'" then s[1...-1].replace /\\'/g, "'"
+      octalNormalised = quoteNormalised.replace /\\([0btnvfr\\])/, (match, c) ->
+        {0:"\0", b:"\b", t:"\t", n:"\n", v:"\v", f:"\f", r:"\r", "\\":"\\"}[c]
+      octalNormalised.replace /\\x([0-9a-f]{2})|\\u([0-9a-f]{4})/i, (match, h, u) ->
+        String.fromCharCode parseInt (h ? u), 16
     isDuplicate = (x) ->
       mx = x.match /^['"]/
       (y) ->
         return true if y is x or +y is +x
         my = y.match /^['"]/
         if mx and my
-          return true if normalise(x) is normalise y
+          return true if normaliseString(x) is normaliseString y
         else if mx
-          return true if y is x[1...-1]
+          return true if y is normaliseString x
         else if my
-          return true if x is y[1...-1]
+          return true if x is normaliseString y
         false
     for prop in @properties
       prop = prop.variable if prop.isComplex()

test/strict.coffee

@@ -70,7 +70,11 @@ test "#2333: more duplicate property prohibitions", ->
   strict '{.1:0, 1e-1:0}'
   strict '{100:0, 1e2:0}'
   strict '{"\\0":0, "\\x00":0}'
+  strict '{"\\n":0, "\\x0A":0}'
+  strict '{"\\\\":0, "\\x5c":0}'
   strict 'a = 0; {a, "a":0}'
+  strict "{'\\'a':0, \"'a\":0}"
+  strict "{'\\\\a':0, '\\\\a':0}"
   strictOk '{0:0, "0x0":0}'
   strictOk '{"a":0, "\'a\'":0}'