The Current table contains the character set used to read input and print output. This table may also contain entities such as SGML entities, etc. Note that the default tables provided with the package are hard-coded in the C code. User-defined tables must be provided in the format described above. In either case, the tables provide the ISO 10646 code associated with the character.
Some functions require processing using the Reference Table as a next step.
Finally, the reverse process is applied to output the desired result. The Current Table is first consulted with the ISO 10646 code of the output character as the key. If the character is present in that table, the table provides the mapping to the current character set and the character is displayed. Otherwise, if the character does not belong to the current character set, the External Entity Table is consulted to determine the appropriate external entity, which is then output.