Add C implementation; separate and package Python and C implementations #3
Conversation
|
@rmonat I'd be glad if you could have a quick look to check the implementation vs. the formal semantics at some point, but I'm in no hurry. |
| } | ||
|
|
||
| /* Precondition: [1 <= d->month <= 12]. The returned day is always [1] */ | ||
| void dc_add_months(dc_date *ret, const dc_date *d, const long int months) { |
There was a problem hiding this comment.
In OCaml add_months_to_first_of_month_date is recursive, I think it is missing here? (ie when |months| >= 12)
There was a problem hiding this comment.
hm, indeed, I changed how this function works a bit and that strays away from what's been proved.
This implementation uses a direct arithmetic computation that should be equivalent to the recursive definition.
And it was actually wrong because it used modulo computation on months in range [1, 12] ; hopefully just shifting by -1 during the computation should ensure a valid date is returned.
On that note: I think you could do something similar to my Python implementation. The testcases are just defined in CSV files to ensure portability :) |
|
I'm not sure it's worth the extra hassle, but we may want to just have a C implementation, and then OCaml/Python modules referring to this one... |
|
I took your remarks into account and implemented the CSV tests, with a couple fixes along the way (an off-by-one condition leading to a stack overflow, and a mistake on the I am not sure about this specific case, but regarding OCaml it's often convenient to have a pure implementation that doesn't require linking C code. Also, here I am afraid that, if we go the classical way of binding C functions in OCaml at least, writing the binding will be more work than the OCaml implementation (with the added risk of segfaults). |
|
Great, thanks a lot @AltGr! Feel free to do a new opam release if you require it for Catala |
TODO: add tests for the C implementation! Currently there are none.The C implementation follows closely the OCaml one ; all functions are in reference-passing and reference-returning style, with the return value used to denote errors on functions that may fail.
OCaml, Python and C implementations have been split in
lib_ocaml/,lib_python/,lib_c/subdirectories.The dune build specifications are extended to handle installation of the C artifacts and of the Python package content below
<prefix>/lib/dates_calc/.