What is it ?

This project contains low-level (mostly complete, auto-generated) and high-level (incomplete, manually written) bindings to the isl library.

The end goal is to make it easy to manipulate polyhedral sets and relations in Haskell. Envisioned applications include static analysis, automatic parallelization, cache optimization, tuning of implementations, hardware generation and the like. The high-level interface currently allows defining basic sets like this:

someSet :: forall s. HasCtx s => BasicSet s 2
someSet = BS.mkBasicSet $
  \(x :- y :- Nil) ->
    idx x >=: cst 0 &&: idx x <=: cst 100 &&:
    idx y >=: idx x &&: idx y <=: cst 100

which is an order of magnitude shorter than the corresponding C code! Also, we try very hard to make the API as safe as possible. For example:

• The BasicSet type is indexed by a type variable s corresponding to the isl context, as well as by its number of dimensions.
• BS.mkBasicSet uses the same rank-2 type trick as the ST monad to guarantee that indices cannot exit their scope.

DISCLAIMER: This software is unsupported and of experimental quality only. It may or may not work for your use-case.

That being said, please try it out, break it and file bugs !

How to use it ?

This software is built and packaged with the Nix package manager. The recommended way to use this library is to consume it as a Nix overlay. For example, put this in <some-directory>/default.nix:

with rec {
  nixpkgs-rev = "67bc63f9a7ac1b4d1a7114c88ca1a4df03bfdb0e";
  pkgs = builtins.fetchTarball {
    name = "nixos-19.03";
    url = "https://github.com/NixOS/nixpkgs/archive/${nixpkgs-rev}.tar.gz";
    sha256 = "0jzy9kd81dz1v0by3h0znz3z6bmpll3ssza5i5f14j2q54ib145g";
  };
 
  isl-bindings-rev = "f462de33568a6fe0edc1b6d08da453a4c23cda2b";
  isl-bindings = builtins.fetchGit {
    name = "isl-bindings";
    url = "https://github.com/gdeest/isl-bindings";
    rev = isl-bindings-rev;
  };
};
 
import pkgs {
  overlays = [ (import isl-bindings) ];
}

and this in <some-directory/shell.nix>:

with import ./.;

mkShell {
  name = "isl-dev-env";
  buildInputs = [
    (haskellPackages.ghcWithPackages(ps: with ps; [isl-bindings isl-bindings-hl]))
    cabal-install
  ];
}

Typing nix-shell within that directory will drop you in a shell environment with Cabal, ghc and isl-bindings available ! We can check that everything is fine with:

$ ghci -package isl-bindings-hl

If ghci loads successfully, you are good to go !