diff --git a/macro.inc.php b/macro.inc.php
index 460a527..ee18476 100644
--- a/macro.inc.php
+++ b/macro.inc.php
@@ -31,6 +31,52 @@ function macro_INTERVAL($proc, $spec)
   return $sec;
 }
 
+/**
+ * @global
+ */
+function macro_WEEK_DATE($proc, $spec)
+{
+  $parts = explode(" ", $spec);
+  $dow_str = $parts[0];
+  $time_str = $parts[1];
+
+  $day = 0;
+  switch ($dow_str) {
+    case 'MONDAY':
+      $day = 0;
+      break;
+    case 'TUESDAY':
+      $day = 1;
+      break;
+    case 'WEDNESDAY':
+      $day = 2;
+      break;
+    case 'THURSDAY':
+      $day = 3;
+      break;
+    case 'FRIDAY':
+      $day = 4;
+      break;
+    case 'SATURDAY':
+      $day = 5;
+      break;
+    case 'SUNDAY':
+      $day = 6;
+      break;
+    default:
+      throw new Exception("Bad day of week: $spec");
+      break;
+  }
+
+  $stamp = strtotime($time_str);
+  if($stamp === false)
+    throw new Exception("Bad time: $spec");
+
+  $stamp += $day * 24 * 60 * 60;
+
+  return $stamp;
+}
+
 /**
  * @global
  */