Re: "Coding system"? Eh?

["François Pinard" <pinard@iro.umontreal.ca>]

Lars Magne Ingebrigtsen <larsi@gnus.org> écrit:

> A character set is an encoding in normal usage.  Quoth RFC2045:

>    Multi-octet coded character sets and switching techniques make the
>    situation more complex. For example, some communities use the term
>    "character encoding" for what MIME calls a "character set", while
>    using the phrase "coded character set" to denote an abstract mapping
>    from integers (not octets) to characters.

There is another distinction between MIME and ISO terminology.  Roughly
said, MIME considers a character set as mapping possible code values to
an encoding of those (often trivial), while ISO consider a character set
as a mere set of characters, not necessarily covering all code positions.
It is sometimes needed to make the set union of many ISO character sets
to get the equivalent of a MIME character set.

P.S. - Take everything I say with a grain of salt.  People which are deep
in these matters are quite susceptible to the detailed wording, and for such
strict readers, I've almost no chance of expressing myself correctly! :-)

-- 
François Pinard                            mailto:pinard@iro.umontreal.ca
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