--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/suite_aggrs/rand-sig.lua	Fri Jan 21 15:42:29 2022 +0100
@@ -0,0 +1,54 @@
+require"config"
+
+-- assure aggr chars are present in pairs (can be weighted, though), to avoid
+-- inf loops
+if string.match(types,'{') and not string.match(types,'}') then types = types..'}' end
+
+rtypes   = "v"..types
+
+
+function mkstruct(n_nest)
+  local s = "{"
+
+  repeat
+    local id = math.random(#types)
+    local t = types:sub(id,id)
+    s = s..mktype(t, n_nest)
+  until t == '}'
+
+  return s
+end
+
+function mktype(t, n_nest)
+  -- ignore new structs if above depth limit
+  if t == '{' then
+    if n_nest < maxaggrdepth then
+      return mkstruct(n_nest + 1)
+    else
+      return ''
+    end
+  end
+
+  -- if '}', without any open, use empty struct
+  if n_nest == 0 and t == '}' then
+    return "{}"
+  end
+
+  return t
+end
+
+
+math.randomseed(seed)
+local id
+for i = 1, ncases do
+  id = math.random(#rtypes)
+  local nargs = math.random(minargs,maxargs)
+  local sig   = { mktype(rtypes:sub(id,id), 0) }
+  for j = 1, nargs do
+    id = math.random(#types)
+    sig[#sig+1] = mktype(types:sub(id,id), 0)
+  end
+  io.write(table.concat(sig))
+  io.write("\n")
+end
+