index d1d98fe1b8dbb8540717e3fb95a2ea7ace6e0ba7..3735988db1b4dd9439d2b711f9ebeccd663ccf1f 100644 (file)
<para>
The <filename>isn</filename> module provides data types for the following
international product numbering standards: EAN13, UPC, ISBN (books), ISMN
- (music), and ISSN (serials). Numbers are validated on input, and correctly
- hyphenated on output.
+ (music), and ISSN (serials). Numbers are validated on input according to a
+ hard-coded list of prefixes; this list of prefixes is also used to hyphenate
+ numbers on output. Since new prefixes are assigned from time to time, the
+ list of prefixes may be out of date. It is hoped that a future version of
+ this module will obtained the prefix list from one or more tables that
+ can be easily updated by users as needed; however, at present, the
+ list can only be updated by modifying the source code and recompiling.
+ Alternatively, prefix validation and hyphenation support may be
+ dropped from a future version of this module.
</para>
<sect2>