diff --git a/srcgen2/xats2js/srcgen1/DATS/js1emit_dynexp.dats b/srcgen2/xats2js/srcgen1/DATS/js1emit_dynexp.dats
index f5b1f1e14..81912c471 100644
--- a/srcgen2/xats2js/srcgen1/DATS/js1emit_dynexp.dats
+++ b/srcgen2/xats2js/srcgen1/DATS/js1emit_dynexp.dats
@@ -1838,10 +1838,10 @@ i1tnmfpr(filr, itnm);strnfpr(filr, " // try\n"))
 //
 val () =
 (
-nindfpr(filr, nind);
-strnfpr(filr, "try {\n");
-f0_i1tnmcmp(env0, itnm, icmp);
-strnfpr(filr, "} catch(");i1valjs1(filr, iexn);strnfpr(filr, ") {\n"))
+nindstrnfpr
+(filr, nind, "try {\n");f0_i1tnmcmp(env0, itnm, icmp);
+nindstrnfpr
+(filr, nind, "} catch(");i1valjs1(filr, iexn);strnfpr(filr, ") {\n"))
 //
 val () = // enter
 envx2js_incnind(env0,2(*++*))
diff --git a/srcgen2/xats2js/srcgen1/TEST/JS/DATA/mytest11.dats b/srcgen2/xats2js/srcgen1/TEST/JS/DATA/mytest11.dats
index 1a012b4e9..b4b410e58 100644
--- a/srcgen2/xats2js/srcgen1/TEST/JS/DATA/mytest11.dats
+++ b/srcgen2/xats2js/srcgen1/TEST/JS/DATA/mytest11.dats
@@ -1,4 +1,4 @@
-(* ****** ****** *)
+* ****** ****** *)
 (* ****** ****** *)
 #staload UN =
 "prelude/SATS/unsfx00.sats"
@@ -25,6 +25,7 @@
 (* ****** ****** *)
 (* ****** ****** *)
 //
+(*
 val fact = 
 fix
 f(x: sint): sint =>
@@ -32,10 +33,59 @@ if x > 0 then x * f(x-1) else 1
 //
 val (   ) = println("fact(10) = ", fact(10))
 //
+*)
+//
 (* ****** ****** *)
 (* ****** ****** *)
-
-val () = $raise ErrorExn()
+//
+datatype
+tree(a:type+) =
+| tree_nil of ()
+| tree_cons of (tree(a), a, tree(a))
+//
+fun
+<a:type>
+tree_isAVL
+(xs: tree(a)): bool =
+(
+try
+let
+val _ =
+auxlst(xs) in true
+end
+with ~NotAVL() => false)
+where
+{
+//
+excptcon NotAVL
+//
+fun
+max
+( x: sint
+, y: sint): sint =
+(if x >= y then x else y)
+//
+fun
+auxlst(xs) =
+(
+case+ xs of
+|
+tree_nil
+((*void*)) => 0
+|
+tree_cons
+(xs1, _, xs3) =>
+let
+val h1 = auxlst(xs1)
+val h3 = auxlst(xs3)
+in
+  if
+  abs(h1-h3) <= 1
+  then 1 + max(h1, h3) else $raise NotAVL()
+end
+)
+//
+} (*where*) // end of [tree_isAVL(xs)]
 
 (* ****** ****** *)
 (* ****** ****** *)