global-functions: $Grep: use length from variable

CONTRIBUTIONS.md

@@ -38,6 +38,7 @@ Add yourself to the list,
 * Alex Maier
 * Andrea Ruffini Perico
 * Andrew Cox
+* Benjamin Newman
 * Christoph Boss (@Kampfwurst)
 * Daniel Ziegenberg (@ziegenberg)
 * Devin Dean (@dd2594gh)

global-functions.rsc

@@ -726,11 +726,14 @@
   }
 
   :do {
-    :local Line [ :pick $Input 0 [ :find $Input "\n" ] ];
+    # Do *NOT* try :deserialize here to split lines. It can fail with
+    # scripts, and it *does* fail with global-functions!
+    :local Len [ :find $Input "\n" ];
+    :local Line [ :pick $Input 0 $Len ];
     :if ([ :typeof [ :find $Line $Pattern ] ] = "num") do={
       :return $Line;
     }
-    :set Input [ :pick $Input ([ :find $Input "\n" ] + 1) [ :len $Input ] ];
+    :set Input [ :pick $Input ($Len + 1) [ :len $Input ] ];
   } while=([ :len $Input ] > 0);
 
   :return [];