Re: [xml-dev] Which should come first: code, XML Schema, or binary speci

["G. Ken Holman" <gkholman@CraneSoftwrights.com>]

At 2012-11-02 12:11 +0000, Costello, Roger L. wrote:
>Hi Folks,
>
>I am examining Microsoft Visio.
>
>It is a nice drawing application. You can create neat pictures.
>
>You can save your drawing as a binary file.
>
>You can also save your drawing as an XML file which conforms to an 
>XML Schema for Visio.

Readers of the archive should check out http://Inkscape.org ... the 
native format is SVG XML.  I've converted all of my new work from 
Visio (1994) to Inkscape.  And it's free.

>So there are three components:

Four:

0. Capability/user/performance/conformance specifications.

>1. Code which expresses the capabilities of the application
>
>2. XML Schema which expresses the capabilities of the application
>
>3. Binary specification which expresses the capabilities of the application
>
>In the development of an application which should come first: code, 
>XML Schema, or binary specification?

Step 0 first.  That will give the requisite guidance on the other 
three parts.  I don't think in your example there is a strong order 
to the other three parts as they could be done in parallel.

In your example, where it is a standalone application and the binary 
format is solely for its own use, who cares about what the XML Schema 
is?  Perhaps, then, the code might be done first after the 
specification in order to determine what belongs in an external representation.

In another example, such as when having multiple applications that 
interoperate, there would be a lean towards doing the interchange 
document model first after the specification.  That would then give a 
guide to all applications about the information they have to deal 
with from other applications.

I suspect the Inkscape folks started with the SVG XML specification 
and built their entire product on top of that.  It provided the 
conformance specification and experience with other drawing packages 
provided everything else.  In that case the schema isn't *just* a 
format, it was the birth of the application.  So that breaks my answer.

I just worry that your question is too general.  And it misses the 
point that user/program requirements are top priority and their 
results will hint towards the emphasis needed on the other parts.

Horses for courses.  Each project will have a different profile.  I 
don't think there is a general guide.

I hope this is helpful.

. . . . . . . . Ken

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