1 files changed, 32 insertions, 0 deletions
diff --git a/build-tools/lib/less/tree/operation.js b/build-tools/lib/less/tree/operation.js
new file mode 100644
index 00000000..d2e4d578
--- /dev/null
+++ b/build-tools/lib/less/tree/operation.js
@@ -0,0 +1,32 @@
+(function (tree) {
+
+tree.Operation = function (op, operands) {
+    this.op = op.trim();
+    this.operands = operands;
+};
+tree.Operation.prototype.eval = function (env) {
+    var a = this.operands[0].eval(env),
+        b = this.operands[1].eval(env),
+        temp;
+
+    if (a instanceof tree.Dimension && b instanceof tree.Color) {
+        if (this.op === '*' || this.op === '+') {
+            temp = b, b = a, a = temp;
+        } else {
+            throw { name: "OperationError",
+                    message: "Can't substract or divide a color from a number" };
+        }
+    }
+    return a.operate(this.op, b);
+};
+
+tree.operate = function (op, a, b) {
+    switch (op) {
+        case '+': return a + b;
+        case '-': return a - b;
+        case '*': return a * b;
+        case '/': return a / b;
+    }
+};
+
+})(require('less/tree'));