*RIGHT - moves the cursor right one character, if possible, changing the offset, if necessary.

*HOME - moves the cursor to the beginning of the string, changing the offset, if necessary.

*INSERT - toggles Insert/Overstrike mode. In Insert mode, your function inserts a printable character into the string at the current cursor position, moves the remainder of the string to the right to make room for the inserted character, and positions the cursor just to the right of the inserted character. The printable characters are the characters from space (' ') to tilde ('~') inclusive in the ASCII table. In Overstrike mode, your function overwrites the character (if any) at the current cursor position with a printable character and advances the cursor just to the right of the new character. If the cursor is past the end of the string, your function appends a printable character to the string as long as the string isn't full, regardless of the mode.

*DEL - discards the character at the current cursor position and moves all characters to the right of the cursor position one position to the left.