Add unit tests, fix last_column reporting.

lib/coffee-script/lexer.js

@@ -731,14 +731,15 @@
     };
 
     Lexer.prototype.makeToken = function(tag, value, offsetInChunk, length) {
-      var locationData, token, _ref2, _ref3;
+      var lastCharacter, locationData, token, _ref2, _ref3;
       offsetInChunk = offsetInChunk || 0;
       if (length === void 0) {
         length = value.length;
       }
       locationData = {};
       _ref2 = this.getLineAndColumnFromChunk(offsetInChunk), locationData.first_line = _ref2[0], locationData.first_column = _ref2[1];
-      _ref3 = this.getLineAndColumnFromChunk(offsetInChunk + length), locationData.last_line = _ref3[0], locationData.last_column = _ref3[1];
+      lastCharacter = length > 0 ? length - 1 : 0;
+      _ref3 = this.getLineAndColumnFromChunk(offsetInChunk + (length - 1)), locationData.last_line = _ref3[0], locationData.last_column = _ref3[1];
       token = [tag, value, locationData];
       return token;
     };

src/lexer.coffee

@@ -645,8 +645,12 @@ exports.Lexer = class Lexer
     locationData = {}
     [locationData.first_line, locationData.first_column] =
       @getLineAndColumnFromChunk offsetInChunk
+
+    # Use length - 1 for the final offset - we're supplying the last_line and the last_column,
+    # so if last_column == first_column, then we're looking at a character of length 1.
+    lastCharacter = if length > 0 then (length - 1) else 0
     [locationData.last_line, locationData.last_column] =
-      @getLineAndColumnFromChunk offsetInChunk + length
+      @getLineAndColumnFromChunk offsetInChunk + (length - 1)
 
     token = [tag, value, locationData]
 

test/location.coffee

@@ -16,10 +16,28 @@ x = () ->
 '''
 
 test "Verify location of generated tokens", ->
-  tokens = CoffeeScript.tokens "a = 7"
+  tokens = CoffeeScript.tokens "a = 79"
 
   eq tokens.length, 4
-  a = tokens[0]
+
+  aToken = tokens[0]
+  eq aToken[2].first_line, 0
+  eq aToken[2].first_column, 0
+  eq aToken[2].last_line, 0
+  eq aToken[2].last_column, 0
+
+  equalsToken = tokens[1]
+  eq equalsToken[2].first_line, 0
+  eq equalsToken[2].first_column, 2
+  eq equalsToken[2].last_line, 0
+  eq equalsToken[2].last_column, 2
+
+  numberToken = tokens[2]
+  eq numberToken[2].first_line, 0
+  eq numberToken[2].first_column, 4
+  eq numberToken[2].last_line, 0
+  eq numberToken[2].last_column, 5
+
 
 test "Verify all tokens get a location", ->
   doesNotThrow ->