Adds modify-vars option.

Gruntfile.js

@@ -178,6 +178,18 @@ module.exports = function(grunt) {
           'tmp/customFunctions.css': ['test/fixtures/customFunctions.less']
         }
       },
+      modifyVars: {
+        options: {
+          modifyVars: {
+            // Note the double quotes in 'imgPath'
+            imgPath: '"/somewhere/else"',
+            customPadding: '20px'
+          }
+        },
+        files: {
+          'tmp/modifyVars.css': ['test/fixtures/modifyVars.less']
+        }
+      },
     },
 
     // Unit tests.

README.md

@@ -183,6 +183,13 @@ Default: false
 
 Puts the less files into the map instead of referencing them.
 
+## modifyVars
+Type: `Object`
+
+Default: none
+
+Overrides global variables. Equivalent to ```--modify-vars='VAR=VALUE'``` option in less.
+
 ### Usage Examples
 
 ```js
@@ -198,7 +205,11 @@ less: {
   production: {
     options: {
       paths: ["assets/css"],
-      cleancss: true
+      cleancss: true,
+      modifyVars: {
+        imgPath: '"http://mycdn.com/path/to/images"',
+        bgColor: 'red'
+      }
     },
     files: {
       "path/to/result.css": "path/to/source.less"

docs/less-options.md

@@ -154,3 +154,10 @@ Type: `Boolean`
 Default: false
 
 Puts the less files into the map instead of referencing them.
+
+## modifyVars
+Type: `Object`
+
+Default: none
+
+Overrides global variables. Equivalent to ```--modify-vars='VAR=VALUE'``` option in less.

tasks/less.js

@@ -98,6 +98,12 @@ module.exports = function(grunt) {
 
     var parser = new less.Parser(grunt.util._.pick(options, lessOptions.parse));
 
+    // Equivalent to --modify-vars option.
+    // Properties under options.modifyVars are appended as less variables
+    // to override global variables.
+    var modifyVarsOutput = parseVariableOptions(options['modifyVars']);
+    srcCode += modifyVarsOutput;
+
     parser.parse(srcCode, function(parse_err, tree) {
       if (parse_err) {
         lessError(parse_err, srcFile);
@@ -131,6 +137,15 @@ module.exports = function(grunt) {
     });
   };
 
+  var parseVariableOptions = function(options) {
+    var pairs = grunt.util._.pairs(options);
+    var output = '';
+    grunt.util._.forEach(pairs, function(pair) {
+      output += '@' + pair[0] + ':' + pair[1] + ';';
+    });
+    return output;
+  };
+
   var formatLessError = function(e) {
     var pos = '[' + 'L' + e.line + ':' + ('C' + e.column) + ']';
     return e.filename + ': ' + pos + ' ' + e.message;

test/expected/modifyVars.css

@@ -0,0 +1,4 @@
+.nice-kitty {
+  padding: 20px;
+  background: url('/somewhere/else/nice-kitty.jpg');
+}

test/fixtures/modifyVars.less

@@ -0,0 +1,7 @@
+@imgPath: '/path/to/images';
+@customPadding: 12px;
+
+.nice-kitty {
+  padding: @customPadding;
+  background: url('@{imgPath}/nice-kitty.jpg')
+}

test/less_test.js

@@ -75,6 +75,15 @@ exports.less = {
 
     test.done();
   },
+  modifyVars: function(test) {
+    test.expect(1);
+
+    var actual = grunt.file.read('tmp/modifyVars.css');
+    var expected = grunt.file.read('test/expected/modifyVars.css');
+    test.equal(expected, actual, 'should override global variables');
+
+    test.done();
+  },
   sourceMap: function(test) {
     test.expect(1);