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Message-ID: <4A0F7508.8090705@gmail.com>
Date: Sat, 16 May 2009 21:23:04 -0500
From: Edgar Friendly <thelema314@gmail.com>
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To: Conglun Yao <yaoconglun@gmail.com>, caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Data type representing 'Money'
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X-Spam: no; 0.00; ocaml:01 edgar:98 mills:98 wrote:01 ints:01 caml-list:01 arithmetic:01 short:01 int:01 int:01 data:02 data:02 represented:02 float:03 representing:05 

Conglun Yao wrote:
> Hi all,
> 
> Is there any data type could be used to represent 'Money'  in OCaml,
> similar to BigDecimal.
> I see a lot of programs using float directly. Maybe Num would be better,
> but less document could be found, for example, how to represent 20.27
> 
> Or there already exist a better solution. Thanks for any help.
> 
> Conglun
> 
> 
I'd do fixed point math using Num to count cents (or mills if you really
need) but displaying dollars and cents.  For example: $20.27 would
internally be represented by the number 2027, and use int arithmetic for
exact math.

If you used 63-bit ints, you'd probably get away with not even using
Num, as max_int = 4611686018427387903 would represent the dollar amount
46_116_860_184_273_879.03, just short of 50 quadrillion dollars.

E