Hi there!

First I have to say, that reading this Forum was a real joy for me! Quite a few things to learn and a rather kind of communication. I like that pretty much!

Now to my question:

I'm writing a program that needs to post commands to a server. These commands are designed in a special flavour of XML.
All this works pretty nice.
Now I would like to validate my commands BEFORE I send them to the server. Checking if it is wellformed should be rather simple. But the problem is the logical validation. Imagine a simple example:

Example 1: A simple wellformed XML-command (simplified)

Code:
<root>
   <command>
      <createsomething>
          <parameter1>value1</parameter1>
          <parameter2>value2</parameter2>
      </createsomething>
   </command>
<root>
This command would be valid XML. But it might NOT be a valid command. For example there might be a parameter3 required. Or the values would need to be in a special charset or whatever. All these requirements are defined in a XML-Scheme.

So what I need to do:
- read the scheme
- analyze it
- validate the XML using it

I guess, the real tough part will be, analyzing it.. Imagine the scheme contains something like "if". How can I create some kind of code, that changes, depending on input (the scheme)??

I can't imagine, how to do this and need your help...

BTW: I can't use libxml2 or any other "extra library" that I would have to install.. And the target system is a old linuxbox. *sigh*

Thanks in advance!

frozen