'i' is input operator of language, it must push on stack ascii code or -1 on eof.

ord getc||-1 is excellent, although it's makes impossible to input NULL charaster. Again it's nice question of compatibility that I'm giving up to judge. It will be considered as cheating for sure.

Update: oops, looks like previous version is also lame here (update2: not!)

Update2: some perl black magic here:

• zero is false but "\0" is true.
• contrary to perlop doc's operator precedence, "ord getc||-1;" means "ord(getc)||-1" not "ord(getc||-1)".

Update3: Second claim is lying, see "perldoc perlop/named unary operators"