[DFDL-WG] Fw: DFDL mini-tutorials
Steve Hanson
smh at uk.ibm.com
Mon Jun 2 07:27:14 EDT 2014
I've also reviewed the tutorials with following comments in addition to
Mark's.
Daffodil_Fixed_Values_AveryBibeau.docx
'fixed' checking only takes place if validation is enabled during DFDL
parse or unparse. That aspect is better covered by a tutorial on
validation.
Because 'fixed' also implies a defaulting behaviour, the checking aspect
can not be dealt with in isolation, and needs to be part of a tutorial on
default values.
Daffodil_Trimming_AveryBibeau_3.docx
Mentions textStringJustification but not textNumberJustification or
textBooleanJustification or textCalendarJustification
Doesn't mention 'center' justification
The 'time' example should use logical integers as the element type, and
therefore textNumberJustification and textNumberPadCharacter.
Should also cover padding as the properties are related and often used
together.
As Mark says, the email header example is a poor one to use, as reading
the schema indicates that the spaces are being consumed by the %WSP*; used
in the initiators, and not by the trimming properties at all.
Escape_Block_AveryBibeau.docx
In the DFDL language, defineEscapeScheme is unique in that provides a way
of grouping a specific set of related properties, and referring to them,
instead of carrying them directly on an object. This is not properly
covered.
The dfdl:escapeSchemeRef is key, but is not mentioned in the text and only
appears in the example.
The name DefaultPropertiesEscapeScheme could be better.
extraEscapeCharacter should be extraEscapedCharacters and is not
described.
Escape_Character_AveryBibeau.docx
Same comments as above.
Better to have a single tutorial that covers and contrasts both kinds of
escape scheme.
Steve Hanson
Architect, IBM DFDL
Co-Chair, OGF DFDL Working Group
IBM SWG, Hursley, UK
smh at uk.ibm.com
tel:+44-1962-815848
----- Forwarded by Steve Hanson/UK/IBM on 02/06/2014 10:25 -----
From: Mark Frost/UK/IBM at IBMGB
To: dfdl-wg at ogf.org,
Cc: jgarriss at mitre.org
Date: 13/05/2014 16:32
Subject: Re: [DFDL-WG] DFDL mini-tutorials
Sent by: dfdl-wg-bounces at ogf.org
Hi All,
I've had a read over these mini-tutorials, and think they're a great intro
to specific features. In particular the style is clear and brief, and
formatting is readable and attractive.
It'd be great to weave these into the existing 'lessons' available at
http://www.ogf.org/dfdl/. That could be an opportunity to polish the
presentation of the lessons :
existing lessons are not very high-profile in web searches (perhaps due to
being pdfs linked only in the sidebar of the ogf site). A separate section
with an introduction (and html content?) could help
some cross-links between the lessons and tutorials would be handy - eg.
lesson 4 covers fixed-length data, where trimming is often useful
a little colour and formatting as used in these tutorials aids readability
these tutorials use an XML format for presenting logical infosets, where
as the lessons use a more generic style without xml tags. I wonder if
using an XML style presentation might confuse some readers that an infoset
"is" XML or the purpose of DFDL is to create XML?
w3schools is an example of a tutorial style I find very effective :
http://www.w3schools.com/schema/schema_intro.asp
Below are a few specific points that came to mind in each of the
mini-tutorials -
Daffodil_Fixed_Values_AveryBibeau.docx
discussion of schema vs. dfdl properties would be useful (explain why
'fixed' is not in the dfdl namespace)
could also cover the defaulting behaviour of xs:fixed (it works like
xs:default), which makes it more powerful than an equivalent enumeration
facet with a single value.
Daffodil_Trimming_AveryBibeau_3.docx
email header example is a little confusing as it uses %WSP*; in
dfdl:initiator, to consume unwanted whitespace, when the tutorial is about
padding/trimming
Escape_Block_AveryBibeau.docx
cross ref to escape character tutorial would be useful when published
"Escaping is a useful capability for using alternative data representation
that includes the separator character"
- more generally, all in-scope markup including separators
- being more explicit might help some readers : that escaping is necessary
to represent characters in logical values that would otherwise be
interpreted as markup
CSV is a good real-world example that could be included.
Escape_Character_AveryBibeau.docx
cross ref to escape block tutorial would be useful when published
"Escape characters can be used to essentially ignore the following
separator character in an element."
- more generally, all in-scope markup including separators
- being more explicit might help some readers : that escaping is necessary
to represent characters in logical values that would otherwise be
interpreted as markup
"defineEscapeScheme is required to create properties related to escaping.
This definition exists outside of the default properties schema."
- I'm not clear what "outside default properties schema" means here
Regarding possible future topics, I'd suggest leaving
inputValueCalc/outputValueCalc for later as these aren't yet available in
the IBM implementation.
Regards,
Mark
Mark Frost
IBM United Kingdom
Software Engineer
Hursley Park
IBM DFDL, IBM Integration Bus
Winchester
SO21 2JN
Phone:
+44 (0)1962 817009
England
e-mail:
frostmar at uk.ibm.com
From: "Cranford, Jonathan W." <jcranford at mitre.org>
To: "dfdl-wg at ogf.org" <dfdl-wg at ogf.org>,
Cc: "Garriss Jr., James P." <jgarriss at mitre.org>
Date: 15/04/2014 16:30
Subject: [DFDL-WG] DFDL mini-tutorials
Sent by: dfdl-wg-bounces at ogf.org
DFDL Working Group,
Attached are four mini-tutorials written by Avery Bibeau, a high school
student. James Garriss of MITRE is mentoring him on a school project which
includes writing tutorials for DFDL.
The idea is that these mini-tutorials could be folded into tutorials in
the future more in line with the existing DFDL tutorials at
www.ogf.org/dfdl. Avery is contributing these mini-tutorials to the
Working Group with the hope that he would be credited in the tutorials.
Any feedback would be appreciated.
Also, below is a list of topics he's planning to work on. If you see
topics that aren't implemented in either of the implementations, please
let us know, as he is only trying to write tutorials on features that he
can test in the existing implementations.
* asserts
* discriminators
* input value calculations
He had planned to do a mini-tutorial on default values, but had problems
testing his examples in both implementations because apparently support
for default values is not quite implemented yet.
Thanks in advance,
--
Jonathan W. Cranford
Senior Information Systems Engineer
The MITRE Corporation (http://www.mitre.org)
[attachment "Daffodil_Fixed_Values_AveryBibeau.docx" deleted by Mark
Frost/UK/IBM] [attachment "Escape_Block_AveryBibeau.docx" deleted by Mark
Frost/UK/IBM] [attachment "Escape_Character_AveryBibeau.docx" deleted by
Mark Frost/UK/IBM] [attachment "Daffodil_Trimming_AveryBibeau_3.docx"
deleted by Mark Frost/UK/IBM] --
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