Bytes and Unicode
The Shen reader reads unsigned 8 bit bytes into unit strings and parses these strings into other tokens as
required. The function 'n->string' maps a code point to the corresponding unit string. It is consistent with the Shen specification to extend the
domain of this function to incorporate extended ASCII or Unicode, but the mentioned code points must be
supported. The function 'string->n' is the inverse of 'n->string'.