Re: [lp-ca-on] tax software design considerations

[Greg Knittl]

Hi Allan,

Looks interesting. R seems to be a free language. Able to output in XML 
which is my best guess as to the required format.
I have no knowledge of R at all. Can you write sample code to read and 
execute something like:
A=B+C
B=D+E
F=C+D
It would be good if it could detect dependency loops - There is at least 
one circular calculation in the Income Tax Act (ITA)
if you want to deduct Foreign Non-Business Income Tax - see forms 
T2209/T2036

https://github.com/charliesome/makefile-1-2-3 uses make to manage the 
dependencies and bash to do the calculations
I like this approach because it separates and exposes the dependencies 
and calculations. The tools are libre, widely available
and easily extensible. I think it would be possible to carry descriptive 
information through the process.
I think it would be possible to adapt it to income tax which is cell 
based but not exactly a grid layout.
It would be possible to write the calculations in bash to start with to 
avoid creating a formula language and simplify the compilation step.
On the downside it's definitely "clunky" to treat each variable as a file.
make has it's issues: 
http://www.conifersystems.com/whitepapers/gnu-make/ . Perhaps there are 
better libre dependency managers.

Maybe simplest is to write a program that builds Libre Office 
spreadsheet(s) based on a rules file and then a separate input file of 
user values...
But that will create dependencies on the Libre Office internal format...

Greg

On 16-05-24 11:24 PM, Allan Zhang wrote:
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> What about R? It would be extremely easy to do these calculations and output in 
> an appropriate form.
>
>
>
> - -------- Original Message --------
> From: Greg Knittl <address@hidden>
> Sent: May 24, 2016 10:54:35 PM EDT
> To: address@hidden
> Subject: [lp-ca-on] tax software design considerations
>
> Income tax software has to perform spread-sheet like calculations which
> I believe are more generically known as reactive programming.
> It would be nice to feed the calculation rules into the engine as data
> which means either a compile step or a reflexive language.
> I've written my tax calculations in XSLT 2.0 which can do reactive
> programming via global variables. However it is not reflexive as of 2.0.
> This looks to be available in XSLT version 3.0
> https://www.w3.org/TR/xslt-30/#element-evaluate. I'm not sure if there
> is a libre version of XSLT 3.0.
> Meanwhile I've hardcoded the calculation rules in the XSLT 2.0 code.
>
> There is most likely a better way. Javascript? Lisp?
>
> Greg
>
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