diff --git a/functions.js b/functions.js
index 8c6f43f..b7577c9 100644
--- a/functions.js
+++ b/functions.js
@@ -1,7 +1,7 @@
 const postcssFunctions = {
-  // takes the custom property defined by defineColor or defineColorAlpha, along
+  // takes the custom property defined by a color defining mixin, along
   // with an alpha value and returns the derived css hsla() function.
-  toHSLA(name, alpha) {
+  alpha(name, alpha) {
     const hue = `var(${name}__h)`;
     const saturation = `var(${name}__s)`;
     const lightness = `var(${name}__l)`;