The payment amount must be greater than zero

[Derek Atkins]

Quoting Graham Leggett <minfrin at sharp.fm>:

> Derek Atkins wrote:
>
>> Unfortunately it's not THAT simple.  From the UI, yes, but there are
>> underlying assumptions that the UI is helping enforce.  Entering a
>> negative amount would break those underlying assumptions.
>
> What underlying assumptions? All cashflows can flow in either 
> direction for any number of reasons, the software shouldn't stop 
> figures being negative, that's the user's job, should the user choose 
> to.

Underlying assumptions in the business features that Invoices are always
on sign and Payments are always the other.  A negative payment would
therefore look like an Invoice..  but it's NOT an invoice.. And it would
confuse the payment-merging processing for handling over/under-payments
across multiple invoices.

Feel free to look at src/business/business-core/gncInvoice.c if you want
to try to come up with a better approach.

> Regards,
> Graham

-derek

-- 
       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
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