Re: [Caml-list] [ANN] Datalog-0.1

[yoann padioleau <yoann.padioleau@gmail.com>]

Hi,

How does it compare in terms of performance with other datalog engines?

On Mon, Jan 28, 2013 at 3:11 AM, Simon Cruanes
<simon.cruanes.2007@m4x.org> wrote:
> Hello,
>
> I'm pleased to announce the first (alpha) release of Datalog, a small
> fixpoint engine for the Datalog fragment of logic
> (http://en.wikipedia.org/wiki/Datalog) written in OCaml. The library is
> designed to be used to compute fixpoints of rules, incrementally. It is
> available under the BSD license at https://github.com/c-cube/datalog .
>
> Both a command-line fixpoint computation tool and a functorial library
> are provided. Input files have a prolog-like syntax, but without
> function symbols. The command line tool works like this (the example
> computes the transitive closure of a graph, and then cliques within this
> transitive closure):
>
> $ cat tests/clique10.pl
> reachable(X,Y) :- edge(X,Y).
> reachable(X,Y) :- edge(X,Z), reachable(Z,Y).
> same_clique(X,Y) :- reachable(X,Y), reachable(Y,X).
> edge(0, 1).  % edge from 0 to 1
> edge(1, 2).
> edge(2, 3).
> edge(3, 4).
> edge(4, 5).
> edge(5, 0).
> edge(5, 6).
> edge(6, 7).
> edge(7, 8).
> edge(8, 9).
> edge(9, 10).
> edge(10, 7).
>
> $ ./datalog_cli.native tests/clique10.pl -pattern 'same_clique(1,X)'
> % start datalog
> % parse file tests/clique10.pl
> % process 15 rules
> % computing fixpoint...
> % done.
> % facts matching pattern same_clique(1, X1):
> same_clique(1, 0).
> same_clique(1, 1).
> same_clique(1, 3).
> same_clique(1, 2).
> same_clique(1, 5).
> same_clique(1, 4).
> % max_heap_size: 126976; minor_collections: 0; major collections: 0
>
> The library provides a functor that allows one to create rules (Datalog
> clauses), and add them to a structure that computes their fixpoint
> incrementally (i.e., the fixpoint is updated after each rule is
> inserted). Callbacks can be associated to symbols, to be called whenever
> a fact is derived.
>
> Feedback, comments, or bug reports are very welcome!
>
> Cheers,
>
> --
> Simon Cruanes
>
>
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