Re: appinfo considered harmful. Re: What is the advantage ofRELAXincomparison to Schemas?

[Joe English <jenglish@flightlab.com>]

Jonathan Borden wrote:

> David E. Cleary wrote:
> >
> > But that is just one of the many uses for appInfo. It can be used for many
> > other things than just extra validation checking.
> > [...]
> > Again, nothing in appInfo stops you from schema validating an instance or
> > using its PSVI.
>
> Perhaps you are saying that the sole purpose of an XML Schema is to validate
> an instance or create a PSVI? In this case why corrupt a perfectly good
> schema with something completely outside its purpose?
>
> On the other hand, perhaps you are saying that the purpose of a schema is
> more than validation and/or creation of a PSVI?

IMO, the *primary* purpose of a schema is that it can be given
to a programmer so that she can write programs that will successfully
process and/or produce documents conforming to that schema.

A secondary purpose is that it can be given to an author so that he
can validate his documents against it, to make sure that they will
work when fed to a program designed to process documents conforming
to the schema.

Tertiary purposes include producing a PSVI (which can make the
programmer's job easier), and validation before committing to a
repository and at other stages in the document's lifecycle (which
can streamline workflow).  But the primary purpose of a schema
is still as documentation for programmers and authors.

'appInfo' is useful because it can point to additional sources
of documentation.  Whether or not it is used to augment the PSVI
or perform extra validation seems to me a tertiary issue.



--Joe English

  jenglish@flightlab.com