[xsd-users] License and Portability

[Peter Backes]

Hi Boris,

On Fri, Jul 01, 2011 at 09:00:46PM +0200, Boris Kolpackov wrote:
> Peter Backes <rtc at cdl.uni-saarland.de> writes:
> > The FSF has generally taken the position that you cannot claim 
> > copyright of the output users generate with the help of your program, 
> > except if that program copies some significant amount of its source 
> > code into the output.
> 
> All of the output produced by the XSD compiler is copied from the XSD
> compiler source code.

I disagree.  The XSD compiler generates the source code by systematic 
transformations from the schema.  In fact, that is just what a compiler 
is supposed to do.  No code is copied from the XSD compiler source code.

Of course, XSD generates the code according to certain programming 
idioms and makes use of some basic code snippets that are present in 
the XSD compiler.  But these are not copyrighted.  They lack 
originality and/or copyrightability: You cannot claim a copyright a 
programming idiom or pattern or on basic code snippets.

> There is no C++ code (or any other kind of 
> programming language-like code) in the input (which is XML Schema).

Nor is there any assembler code in the input you pass to the GCC C 
compiler.  In fact, compilers are translators.  What you pass as the 
input is in a different language from what it gives you as output.  
This is exactly the idea.

So it does not matter that there is no C++ code in the input, and the 
GPL FAQ makes no restriction in this respect.

All that matters is that all the output is determined by the input 
completely.  There is no piece of copyrightable code that is inserted 
regardless of the input.  (Contrary to bison, which does copy 
substantial pieces of code from its own source code into the output; 
irrespective of what the input is.)  Please correct me if I got this 
wrong, but it was my impression from looking at the generated code.

> So I believe we are in agreement with the FSF when we claim copyright
> on the generated code.

I disagree.  In fact, you are in perfect disagreement. ;)  You claim to 
be able to do legally what the FSF terms as "legally impossible".

Why do you need to make this questionable claim on the output of your 
compiler?  Isn't it sufficient to make a claim on your own libxsd 
header code?

Regards
Peter

-- 
Peter Backes, rtc at cdl.uni-saarland.de            Office 403
Compiler Design Lab, Saarland University         Campus E1 3
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