1 files changed, 4 insertions, 0 deletions
diff --git a/lib/js/urweb.js b/lib/js/urweb.js
index d3c144b9..4a447a5b 100644
--- a/lib/js/urweb.js
+++ b/lib/js/urweb.js
@@ -154,6 +154,10 @@ function pfl(s) {
     throw "Can't parse float: " + s;
 }
 
+function cat(s1, s2) {
+  return s1 + s2;
+}
+
 function whine(msg) {
   alert(msg);
   throw msg;