An if {} then {} construct exists in Tcl, where then is an optional noise word, but Tcl has no equivalent to Perl's xor operator, so his comparison is still bogus. The Perl equivalent would be if () {} which is only seven characters (and Tcl accepts an equivalent if {} {} syntax) but it is still wrong because our questioner is talking about using xor as another type of fat comma in contexts where an actual comma or fat comma would cause perl's parser to extract an unintended meaning for the expression.