The following method is an implementation of the ROT13 simple cipher in 4D:

// ROT13 encoding takes a string and rotates the alphabet 13 letters, // the same method can be used for both encoding and decoding ROT13 C_TEXT($1;$input_t) // input string - to be ROT13 encoded C_TEXT($0;$output_t) // output string - encoded in ROT13 C_LONGINT($char_l) // character code used for rotation C_LONGINT($len) // length of string C_LONGINT($a) // loop iteration counter C_TEXT($tmp) // temp var for chars Case of  :(Count parameters=2)    $char_l:=Character code($1)    $output_t:=Char($char_l)    If (($char_l>64) & ($char_l<78))       $output_t:=(Char($char_l+13))    End if    If (($char_l>77) & ($char_l<91))       $output_t:=(Char($char_l-13))    End if    If (($char_l>96) & ($char_l<110))       $output_t:=(Char($char_l+13))    End if    If (($char_l>109) & ($char_l<123))       $output_t:=(Char($char_l-13))    End if  :(Count parameters=1)    $input_t:=$1    $len:=Length($input_t)    $output_t:=""    For ($a;1;$len)       EXECUTE METHOD(Current method name;$tmp;Substring($input_t;$a;1);"rotate")       $output_t:=$output_t+$tmp    End for End case $0:=$output_t

If the method is saved as UTIL_rot13 is can be used like this:

$rotText:=UTIL_rot13("This is some sample text")

In the above example $rotText would be equal to: "Guvf vf fbzr fnzcyr grkg"

Converting this back with the same method would be done like this:

$rotText:=UTIL_rot13("Guvf vf fbzr fnzcyr grkg")