Looks good, Jeff - with the caveat though
that even though the core is MUST and the specializations are RECOMMENDED
or OPTIONAL, a specialization may introduce behavior that overrides the
core.
In other words, all behavior, core and
specialized, is overrideable.
Michael Priestley
Lead IBM DITA Architect
http://dita.xml.org/blog/25
"Ogden, Jeff"
<>
10/02/2007 02:08 PM
To
<>
cc
Subject
[dita] MUST, SHOULD, and MAY, some key
words from RFC 2119
Included below are some words taken from
RFC 2119 on “Key words for use in RFCs to Indicate Requirement Levels".
I think we are going to need to use this or a similar approach in the DITA
standard.
1. MUST This word, or the terms "REQUIRED"
or "SHALL", mean that the
definition is an absolute requirement
of the specification.
2. MUST NOT This phrase, or the phrase
"SHALL NOT", mean that the
definition is an absolute prohibition
of the specification.
3. SHOULD This word, or the adjective
"RECOMMENDED", mean that there
may exist valid reasons in particular
circumstances to ignore a
particular item, but the full
implications must be understood and
carefully weighed before choosing
a different course.
4. SHOULD NOT This phrase, or the
phrase "NOT RECOMMENDED" mean that
there may exist valid reasons
in particular circumstances when the
particular behavior is acceptable
or even useful, but the full
implications should be understood
and the case carefully weighed
before implementing any behavior
described with this label.
5. MAY This word, or the adjective
"OPTIONAL", mean that an item is
truly optional. One vendor
may choose to include the item because a
particular marketplace requires
it or because the vendor feels that
it enhances the product while
another vendor may omit the same item.
An implementation which does
not include a particular option MUST be
prepared to interoperate with
another implementation which does
include the option, though perhaps
with reduced functionality. In the
same vein an implementation
which does include a particular option
MUST be prepared to interoperate
with another implementation which
does not include the option
(except, of course, for the feature the
option provides.)
To see the full RFC (its short), see: http://www.ietf.org/rfc/rfc2119.txt?number=2119
Note that as we split the DITA Specification
into multiple specifications, that an entire specification may be REQUIRED,
RECOMMENDED, or OPTIONAL, but within the individual specifications there
will be items that are REQUIRED, RECOMMENDED or which are OPTIONAL.
So, if I take the summary from Michael’s
recent note:
-
everyone
needs to support the core;
-
specialized
support (beyond core defaults) for the specialized parts of the spec are
optional but encouraged, and should represent an established user community;
-
specialized
support (beyond core defaults or standard specialization defaults) for
non-standardized user specializations are up to the user or their partners
to provide
I can rewrite it using the RFC terms as follows:
-
everyone
MUST support the core;
-
specialized
support (beyond core defaults) for the specialized parts of the spec are
RECOMMENDED, and MUST represent an established user community;
-
specialized
support (beyond core defaults or standard specialization defaults) for
non-standardized user specializations is OPTIONAL and up to the user or
their partners to provide.
Michael, how did I do?
-Jeff
