Code generation for GnuCash payroll witholding

[Michael D. Crawford]

I posted the following to payswell-devel earlier today. I thought you'd 
be interested too. You can follow along by reading the archives if you 
don't want to subscribe. There's just a delay of several hours before 
new posts show up:

http://sourceforge.net/mailarchive/forum.php?forum_id=45168
http://www.payswell.org/

In response to suggestions that we write Guile scripts to enable 
witholding in GnuCash, I said:

I think the reason that GnuCash doesn't already support payroll taxes is 
not the dificulty of writing the code, but capturing logic from the 
plethora of payroll tables published by all the world's national, state 
and provincial governments. Canada's formulas alone take up eighty-seven 
pages. In the US, there is the federal government, fifty states that 
often do things quite differently from each other, and all the 
territories like Puerto Rico, not to mention Washington D.C. If all 
these tax tables were printed in hardcopy, you could kill a man with 
their weight!

But I think that working it out in a visual way with spreadsheets is a 
good way to approach the problem of distilling all this complexity into 
black-and-white business logic. And then, guess what I realized you 
could do, if all the spreadsheets were constructed in a uniform way:

OpenOffice documents are really just zipped XML files. The XML DTD, or 
maybe there is a schema, is documented. Once we had all the spreadsheets 
worked out, someone could write a code generator in Perl, Python, Scheme 
or whatever was convenient, and GENERATE Guile code directly from the 
spreadsheet XML for GnuCash to use!

The beauty of this, you see, is that I expect that by the time we have 
global coverage, most of the spreadsheets won't have been written by 
programmers like you and I, but by regular office workers, people who 
don't know any more about computers than what Microsoft Office enables 
them to do. But by writing such a code generator, we would have 
transformed these people into computer programmers! Imagine the potential!

Intrepidly,

Mike
-- 
Michael D. Crawford
GoingWare Inc. - Expert Software Development and Consulting
http://www.goingware.com
crawford at goingware.com

   Tilting at Windmills for a Better Tomorrow.

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