From 6df4e4897681dae1668d582bbb64bfebf0cbc3e3 Mon Sep 17 00:00:00 2001
From: Kevin Gillette <extemporalgenome@gmail.com>
Date: Fri, 14 Jun 2013 01:06:16 -0600
Subject: [PATCH] Added min and max builtins.

---
 lib/less/functions.js    | 35 +++++++++++++++++++++++++++++++++++
 test/css/functions.css   |  6 ++++++
 test/less/functions.less |  6 ++++++
 3 files changed, 47 insertions(+)

diff --git a/lib/less/functions.js b/lib/less/functions.js
index 361be6f4..016e8a96 100644
--- a/lib/less/functions.js
+++ b/lib/less/functions.js
@@ -266,6 +266,41 @@ tree.functions = {
             throw { type: "Argument", message: "argument must be a number" };
         }
     },
+    _minmax: function (name, args) {
+        args = Array.prototype.slice.call(args);
+        switch(args.length) {
+        case 0: throw { type: "Argument", message: "one or more arguments required" };
+        case 1: return args[0];
+        }
+        var isMin = name == 'min';
+        function f (a, b) {
+            if(!(a instanceof tree.Dimension && b instanceof tree.Dimension)) {
+                return null;
+            }
+            var ua = a.unify();
+            var ub = b.unify();
+            if(ua.unit.compare(ub.unit) != 0) {
+                return null;
+            }
+            var val = ua.compare(ub);
+            if(isMin && val > 0 || !isMin && val < 0) {
+                return b;
+            }
+            return a;
+        }
+        var val = args.reduce(f);
+        if(val !== null) {
+            return val;
+        }
+        return new(tree.Anonymous)(name +
+            "(" + args.map(function (a) { return a.toCSS(); }).join(', ') + ")");
+    },
+    min: function () {
+        return this._minmax('min', arguments);
+    },
+    max: function () {
+        return this._minmax('max', arguments);
+    },
     argb: function (color) {
         return new(tree.Anonymous)(color.toARGB());
 
diff --git a/test/css/functions.css b/test/css/functions.css
index d1392c35..12a831a0 100644
--- a/test/css/functions.css
+++ b/test/css/functions.css
@@ -81,6 +81,12 @@
   pow: 64px;
   pow: 64;
   pow: 27;
+  min: min(3, 3em);
+  min: min(3pt, 3em);
+  min: 1%;
+  min: min(1%, 5px);
+  min: 3pt;
+  max: 3;
   percentage: 20%;
   color: #ff0011;
   tint: #898989;
diff --git a/test/less/functions.less b/test/less/functions.less
index 337e9eb6..929595b6 100644
--- a/test/less/functions.less
+++ b/test/less/functions.less
@@ -87,6 +87,12 @@
   pow: pow(8px, 2);
   pow: pow(4, 3);
   pow: pow(3, 3em);
+  min: min(3, 3em);
+  min: min(3pt, 3em);
+  min: min(1%, 5%);
+  min: min(1%, 5px);
+  min: min(1pc, 3pt);
+  max: max(1, 3);
   percentage: percentage((10px / 50));
   color: color("#ff0011");
   tint: tint(#777777, 13);