[Caml-list] [ANN] exenum.0.6: exhaustive enumerations for datatypes

[Caml-list] [ANN] exenum.0.6: exhaustive enumerations for datatypes

[Didier Le Botlan]

Hi list,

Let me introduce exenum, the "exhaustive enumeration"(1) library.

<shameless teaser>
You all probably wonder what "the" 42,000th lambda-term is. It happens 
to be (((fun x -> v) (v v)) ((x x) v))   (2)

As for "the" 10^400th lambda-term, it is
((((((fun x -> (v v)) ((fun v -> y) (fun x -> x))) ((fun v -> (x 
x))[...and 20 more lines...]


(1) where "exhaustive" means that every value (of the given datatype) is 
eventually enumerated.

(2) where variables are restricted to "x", "y", "u", "v".

</teaser>


In short :

  - exenum makes it easy to build enumerations for any datatype.

  - Very handy to carry out intensive unit testing
(Students' motto : "If you know your code is unsound, test it anyway, it 
might work by accident").

  - exenum is inspired by FEAT for Haskell.

  - Impress coq's users with statements such as: "I have successfully 
checked my code up to index 17 !"

  - Quick overview and API on the homepage:
http://exenum.forge.ocamlcore.org/

  - Install with: opam install exenum

* * *

As a side dish, let me mention the oasis- and ocamlbuild-based packaging 
I used for this library.

For quite a while, I had been looking for a neat way to pack an ocaml 
library, that is:
  - Only one main module is "exported" to users (or, say, just a couple 
of modules).
  - The library may define several internal modules, but they should 
remain hidden (that is, as hidden as possible). In particular, they 
should not pollute the global module namespace.

I was not able to find satisfactory examples on the net (most likely, 
though, I have not searched enough).

Finally, I wrote an _oasis file as follows (excerpt):
## Exported library
Library "exenum"
   Path:            src/
   Modules:         ExEnum
   BuildDepends:    exenum.internals
   Install:         true

## This library packs internal modules, so that they may not conflict 
with anything else.
Library "exenum_internals"
   Path:	           src/
   Modules:         Convenience
   InternalModules: Exen, ExtArray, Parts, Shuffle
   FindlibParent:   exenum
   FindlibName:     internals
   Pack:            true

Thus, the internal modules are all packed in an ocaml module 
"Exenum_Internals" (the -pack option of ocamlc). Only the main module 
"ExEnum" and "Exenum_internals" are visible at top-level.

See details at the bottom of:
http://exenum.forge.ocamlcore.org/

--
D. Le Botlan