Arbitrary-precision floating-point decimal type implemented in OCaml. Ported
from Python
decimal module.
It uses Zarith to do biginteger arithmetic.
Opam: https://ocaml.org/p/decimal
This package is licensed under the
Python Software Foundation License v2,
for the sake of simplicity, as it is a derived work of the Python decimal module.
See next section (below) for dune instructions.
$ opam install decimal # if trying out
# (* if trying out: *)
#require "decimal";;
#require "ppx_decimal";;
# (* tell the REPL how to display decimals *)
#install_printer Decimal.pp;;
# (* PPX gives convenience literal syntax *)
Decimal.(0.1m + 0.2m);;
- : Decimal.t = 0.3
# (* default precision is 32 *)
Decimal.(of_int 1 / of_int 3);;
- : Decimal.t = 0.33333333333333333333333333333333
# (* round to decimal places: *)
Decimal.(round ~n:2 (of_int 22 / of_int 7));;
- : Decimal.t = 3.14
In your dune file's executable or similar stanza:
(libraries decimal)
(preprocess (pps ppx_decimal))
Build:
dune build
Try in REPL:
dune utop
The test runner source is in test/decimal_test.ml. It parses and runs the test
cases in test/data/. I am adding test case data files from the
Python snapshot
as I go.
Run current tests:
dune test
Note that, some of the tests don't make sense for the OCaml port and have thus
been deleted. If you ever need to update to new versions of the test files, you
can apply the changes as patches after re-dowloading the relevant *.decTest
files:
git show 07074859567e936b8d170aba5ef58889a4d9d467 | git apply
git show ae0196377fb7a99db7f198f2fb242e6a2fe4541e | git apply