Fw: [dfdl-wg] minutes of call 2005-09-14

[Steve Hanson]

Hi Mike

Re the three escape mechanisms. It is unfortunate that we need a separate
mechanism for the second case (as discussed in the draft spec section 26).

Re the third mechanism for escaping hex literals. An alternative syntax
could be \#0x2C; using 0x to indicate hex.  &#0x2C; would be even better -
but does it cause XML problems?

Regards, Steve


----- Forwarded by Steve Hanson/UK/IBM on 15/09/2005 09:33 -----
                                                                           
             Mike Beckerle                                                 
             <beckerle at us.ibm.                                             
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                                       [dfdl-wg] minutes of call           
             14/09/2005 22:18          2005-09-14                          
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           





Who: Jim Myers, Mike Beckerle, Tara Talbott, Steve Hanson, Geoff Judd, Bob
McGrath

Agenda:

GGF plans - we will have F2F at GGF15. The schedule of our WG sessions at
the GGF15 are not yet set, but we'll have F2F meetings during the
non-scheduled times. We're counting on the fact that most of our DFDL WG
members are focused on DFDL and won't mind the conflict with the rest of
GGF15 much. People should make travel plans for all 3 days M, T, W.

GridForge Forums - these seem to be working now. Will try them when one of
our subcommittees reports back to the broader WG. E.g., scoping or arrays.

Issues list - we made it through items 5 to 15

Issue 5 - resolution. No built-in set of defaults. If you need a property
and your configuration doesn't have one specified then it is an error.
There is a small set of named configurations provided with DFDL each of
which is a self-consistent set of properties. This is probably the set that
we find useful in the primer and other WG docs.

Issue 6 - resolution. change attribute name from 'base' to 'extends'

Issue 7 - belongs on same tracker as 8, 9, 10

Issue 11 - resolution: add an attribute 'byteOrderMarkPolicy' values are:
required, notAllowed, optionalButGenerateOnOutput, optionalButOmitOnOutput
(the generate on output control aspect was not discussed on the call. I
thought of that just now while typing.)

Issue 12 - fix diagram - omission of these types was unintentional. Better
diagram next draft

Issue 13 and 14 - new tracker item - Steve Hanson, Geoff Judd and someone
from MikeB's team at IBM to address

Issue 15 - resolution: each delimiter will grow an extra rep-property for
its regexp variant. E.g., separator will have corresponding separatorRegexp
property. Only one of the two may be specified.

We discussed that separator (or any delimiter) can be a text string, and we
had previously decided that the separatorEncoding attribute would go away
to be replaced by a syntax for expressing hex bytes (not hex character
codes, real non-charset transformed hex bytes) as part of delimiter strng
literals. This same way of putting hex bytes would also be supported as
part of the regexp language so that the regexp language remains able to
include any non-regular expression for a delimiter into a regular
expression.

(Editor's Note: this is a bit tricky. We now have in string literals 3
different escape mechanisms that are different.

1) XML character code specifiers e.g., 'abc&#x2C;def' which is the normal
XML way of specifying the unicode #x2C character code. (This is an XML
standard escape convention.) Used inside a delimiter string this means take
the unicode #x2c code point, figure out what character it corresponds to in
the charset of the data element and use that character. Note that this is
the same thing that 'a' means. Take the 'a' unicode code point, figure out
what character corresponds to 'a' in the charset of the data element, and
look for that.

2) nonXML character code specifiers e.g., 'abc\#x00;def' which is the way
we allow you to put XML-disallowed unicode character codes like #x00 into a
string literal. (This is a DFDL convention). The interpretation here is
exactly like the above. I.e., '\#x2c;' is exactly equivalent to '&#x2c;'
and the charset mapping applies as above. This rule is only needed because
of the XML restriction disallowing certain unicode character codes from the
XML infoset.

3) non-character byte specifiers. E.g., 'abc\%01;\%02;def' which is a
proposed escape syntax that means put the bytes #x01 and #x02 into the
string literal bypassing any considerations of charset, i.e., without
considering them to be character codes in any character set. That is, these
byte values have nothing to do with unicode codepoint values. (This is a
DFDL convention.) The other characters of the string would be treated as
per (1) and/or (2) above.

)