User:This, that and the other/subst and safesubst/subst

Start of template End of template
 * Parameter 1:.
 * Parameter 1 or nothing:.
 * "YEAH" if parameter 1 set, "AWWW" if parameter 1 not set :
 * The same  switch, but with   code: YEAH
 * The same  switch, but with   code:
 * The same  switch, but with   code: