Re: Experiences of XML parser generators for Ada?

[Georg Bauhaus <sb463ba@l1-hrz.uni-duisburg.de>]

Lionel Draghi <Lionel.nospam.Draghi@ada-france.org> wrote:
: Adrien Plisson a ?crit :
: ...
:> well, Ada has nothing to do with w3c. it is the our job, as Ada 
:> programmers to design and implement a library providing those features 
:> (as Xml/Ada does). it shall never be part of the standard.
: 
: Yes, but
: 
:    type Money is range 1 .. 10;
: 
: becomes
: 
:    name="TN" type="xsd:int"
: 
: in WSDL. The range is lost.
: 
: Maybe some more Ada awareness at w3c could have cause this semantics to 
: be included. (If it is, please let me know)

This problem has been discussed during XML Schema design.
In XML Schema you have some form of ranges in the type libraries.

pro: You don't need to bother to make a good external format,
     just lazily copy your data definitions to an XML stream

medium: If you need to carry type information you can make this
     explicit in a type="..." attribute. (This is then not standards
     based, but it gives more flexibility than a parser that says:
     range error at l.1234, and the just stops.)

con: Freezing the range might not meet any expectation but your
     program's

: I don't want client to continuously cause exceptions in my server, just 
: because there is no way to let them know about the limits.

Use 'Valid and so on. Web services or not, I/O is always a possible
source of surprises. :-)  A secure server cannot rely on external input
anyway, I'd guess.

 
: Once more back to strong typing benefits discussion :-)

The flexible solution is Relax NG.