Substring functions; fix a nasty MonoReduce pattern match substitution bug

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/js/urweb.js b/lib/js/urweb.js
index db3c934c..be3d652a 100644
--- a/lib/js/urweb.js
+++ b/lib/js/urweb.js
@@ -353,6 +353,23 @@ function bs(b) { return (b ? "True" : "False") }
 function sub(s, i) { return s[i]; }
 function suf(s, i) { return s.substring(i); }
 function slen(s) { return s.length; }
+function sidx(s, ch) {
+  var r = s.indexOf(ch);
+  if (r == -1)
+    return null;
+  else
+    return r;
+}
+function schr(s, ch) {
+  var r = s.indexOf(ch);
+  if (r == -1)
+    return null;
+  else
+    return s.substring(r);
+}
+function ssub(s, start, len) {
+  return s.substring(start, start+len);
+}
 
 function pi(s) {
   var r = parseInt(s);