From 331ba46cfb1355ac5d699cc040e726bca2b22118 Mon Sep 17 00:00:00 2001
From: Natalie Weizenbaum <nweiz@google.com>
Date: Fri, 9 Dec 2016 13:44:51 -0800
Subject: [PATCH] Allow saturate($number).

---
 CHANGELOG.md           |  2 ++
 lib/src/functions.dart | 23 ++++++++++++++++-------
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d21cf5b1b..9f496a106 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@
 
 * Fix a bug with `@extend` superselector calculations.
 
+* Allow a single number to be passed to `saturate()` for use in filter contexts.
+
 ## 1.0.0-alpha.4
 
 * Add support for bracketed lists.
diff --git a/lib/src/functions.dart b/lib/src/functions.dart
index cdd1cdd69..80ff476e4 100644
--- a/lib/src/functions.dart
+++ b/lib/src/functions.dart
@@ -185,13 +185,22 @@ void defineCoreFunctions(Environment environment) {
             .clamp(0, 100));
   });
 
-  environment.defineFunction("saturate", r"$color, $amount", (arguments) {
-    var color = arguments[0].assertColor("color");
-    var amount = arguments[1].assertNumber("amount");
-    return color.changeHsl(
-        saturation: (color.saturation + amount.valueInRange(0, 100, "amount"))
-            .clamp(0, 100));
-  });
+  environment.setFunction(new BuiltInCallable.overloaded("saturate", [
+    r"$number",
+    r"$color, $amount",
+  ], [
+    (arguments) {
+      var number = arguments[0].assertNumber("number");
+      return new SassString("saturate(${number.toCssString()})");
+    },
+    (arguments) {
+      var color = arguments[0].assertColor("color");
+      var amount = arguments[1].assertNumber("amount");
+      return color.changeHsl(
+          saturation: (color.saturation + amount.valueInRange(0, 100, "amount"))
+              .clamp(0, 100));
+    }
+  ]));
 
   environment.defineFunction("desaturate", r"$color, $amount", (arguments) {
     var color = arguments[0].assertColor("color");