monetary applications [was: Python GUI app to impress the bos s?]

[Dennis Lee Bieber]

Paul Boddie fed this fish to the penguins on Thursday 19 September 2002 
01:14 am:


> It could well be that not many people do financial database
> programming in Python, bizarre and unlikely as that may seem. Taking a
> look at pyPgSQL, as the only database module I have installed that
> actually readily documents such things (and that should tell you
> something), it would seem that monetary amounts are converted to
> floating point numbers - surely the first thing one would want to
> avoid in manipulating financial data. Perhaps people use integers, or
> perhaps other modules provide better decimal support.
>
        If I recall from the c.l.ada group, GNAT's "fixed point" data type is 
implemented as scaled integers, so even that might not pass the spec 
for a monetary type. My VB references are on loan (or currently stuck 
in the Windows environment and unreadable on Linux) so I can't recall 
what VB6 had for fixed/monetary.

        The only language I've ever encountered that had a truely monetary 
safe fixed point data type is COBOL -- which has always used packed BCD 
formats (though where the sign "bit" is stored may vary). COBOL was 
created from the beginning for "business" applications (heck: COmmon 
Business Oriented Language) and was spec'd by a government team. My 
college mainframe required /four/ of the sixteen registers to hold 
/one/ BCD number (32 BCD digits, 2 digits/byte, 16bytes @ 4/register).
 

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