Great idea!  XML revolutionises program input and output. FORTRAN
programmers spend half their life with:
	Column 61 (I2) the number of optional cards describing the FOO.
This is an optional branch of a tree. With TEI processing it's marvellous.
I am trying to convert the molecular community to use XML as standard for
input and output to *existing* programs. If you can achieve it in your
community - great.
>the old days, say in FORTRAN, one used to use namelist input.  In C/C++, one 
>usually wrote a custom driver.  I want to use XML because it appears to make 
>sense.  I have started using SP - and want to build a tree that I can query 
>(kind of like an xrdb interface) for my input parameters.  But, before I 
>embark on this, I was wondering if 1) this makes sense, 2) someone surely
has 
>a simple tree builder/query interface to SP already that I can use so I
don't 
>have to write my own (none jumped out at me when I looked around).
I imagine the simplest way to do this is to write an XML2F77input
processor. This is really a stylesheet application.  If you wait for XSL I
suspect it will solve many of your problems. If you can't wait, then there
may be facilities in JUMBO that could be useful.
	P.