Adding a Payroll calculator

[Andrew Sackville-West]

This is in response to several above.... and my own thoughts on it last 
night.

Derek Atkins wrote:
>
>>Example: scheduleY1()
>>
>>This example is used for calculating the income tax for someone who is
>>married, filing jointly, and earns more then $100,000 according to the
>>IRS 1040 2001 rates. 
>>
>>variables: 
>>[$line41 = wages, $line42 = Tax, scheduleY1 = member function]
>>## Status = married filing joint ##
>>sub scheduleY1(){
>>    my $line41 = shift;
>>    if ($line41 >= 0 && $line41 <= 12000){
>>	$line42 = $line41 * .10;
>>    }elsif ($line41 >= 12000 && $line41 <= 46700) {
>>	$line42 = ((($line41 - 12000)* .15) + 12000);
>>    }elsif ($line41 >= 46700 && $line41 <= 112850) {
>>	$line42 = ((($line41 - 46700)* .27) + 6405);
>>    }elsif ($line41 >= 112850 && $line41 <= 171950) {
>>	$line42 = ((($line41 - 112850)* .30) + 24265.50);
>>    }elsif ($line41 >= 171950 && $line41 <= 307050) {
>>	$line42 = ((($line41 - 171950)* .35) + 41995.50);
>>    }elsif ($line41 > 307050) {
>>	$line42 = ((($line41 - 307050)* .38.6) + 89280.50);
>>    }
>>    return $line42;
> 
> 
> Um, this seems particular hard-coded and not very flexible.  It's even
> WORSE if it's in C, because then the numbers aren't user-settable.
> You /need/ to support this kind of configuration in a user-settable
> method.  How do you propose to do that?
> 
> This is why I'm suggesting scheme, because then you can configure this
> kind of "function" in scheme and users can change the values without
> having to rebuild gnucash.  I'm open to other suggestions, too.  We
> can certainly try to create a generalized "graduated tax" in C, but
> you'd need to figure out some way to allow the user to configure that.
> 

WHy not do something like this:

struct _gncTax
{
   char *          id;
   char *          taxName;   /* Medicare, SSI, Sales,..etc */
   char *          taxType;   /* Payroll, Payroll, Sales  */
   char *          taxCatagory;/* Employee, Salary, Sale */
   gnc_numeric     taxRate;   /* .0145, .062, .893 */
   gnc_numeric     taxFrequency; /* hourly, monthly, unit */
	gnc_numeric	taxFloor; /* minimum value below which tax is NOT applied */
	gnc_numeric	tax Ceiling; /* max value above which tax is NOT applied */
   gnc_commodity * currency;
   gboolean        active;
   char *          language;
   Account *       tax_acc;
};

This allows you to set tax brackets which would work for US graduated 
taxes by setting a different instance for each bracket with min and max 
values set by the user. But it could also apply to "Wage base" taxes 
like Social Security or Unemployment Tax which both only apply to the 
first $x of wage per year. by setting the taxFloor to 0, and taxCeiling 
to $x then you only tax the first $x wages. etc. you couuld hard code a 
default so that if tax Ceiling is $0 then the tax always applies (i.e. 
medicare).

I think we might need something like this as well:

struct _gncPayrollItem
{
   char *          id;
   char *          PIName;   /* name of the item */
   char *          PIType;   /* addition or deduction  */
   Account *          PIAccount;/* account linked to this Item (can be 
blank, can we do that with Account?) */
   gboolean	  taxable; /* some items are taxable */
/* some method of determining which taxes apply??? */
   gnc_numeric     PIAmount;   /* the amount */
   gnc_commodity * currency;
   gboolean        active;
   char *          language;

};

I really don't know what I'm doing here as far as gnc code goes, but it 
works like this. Everything that is part of a paycheck has to be 
associated with an _gncPayrollItem. Each of these items is previsouly 
set-up by the user and linked to the employee. you can have one for 
wages, one for employee mileage reimbursements, one for reported tips 
(and then another one to deduct the employee tips back out), one for 
reclaiming employee advances etc. etc. etc. This idean is stolen right 
out of QB by  the way.... The point is there are lots of other things 
that go on in payroll besides taxes and any reasonable solution, in my 
mind, needs to include these things. So you can have an employee with a 
variety of _gncTax applied and a variety of _gncPayrollItem applied to 
build up the whole transaction.

For those that question the tips portion above it works like this: If 
you have tipped employees (/me) then you have to tax them on their tips 
so their tips are included in the Total Wages before taxes are 
calculated. Then those tips are deducted back out (because the employee 
already has them) out of the final paycheck.

A