No real need:

test {
if ($istok(1.2.3,$1,46)) { goto $1 }
else { goto default }
:1
echo -a 1
goto endcase
:2
echo -a 2
goto endcase
:3
echo -a 3
goto endcase
:default
echo -a DEFAULT
:endcase
}

/test 1
/test 2
/test 3
/test ANYTHING ELSE.