Package "rdet"

Title:	Runtime determinacy checker
Rating:	Not rated. Create the first rating!
Latest version:	1.0.2
SHA1 sum:	8caf683808880c34cb3cf29f3bb0a956789557db
Author:	Raivo Laanemets http://rlaanemets.com/
Home page:	https://github.com/rla/rdet

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Details by download location

Version	SHA1	#Downloads	URL
0.0.1	c7cfc59602962142784d9ece67b576446aab7619	89	http://packs.rlaanemets.com/rdet/rdet-0.0.1.tgz
0.0.2	3f3a15b6cbdb1e0064e2002f07dbfe5979eb6f74	20	https://github.com/rla/rdet.git
1.0.0	2adddfdbcab4ad3d0970f2b4790b75b0ea2d22a5	6	http://packs.rlaanemets.com/rdet/rdet-1.0.0.tgz
	b2f02c0802e6db9af27a317c84f309d855e78029	5	https://github.com/rla/rdet.git
1.0.1	67d43ab75ce1c1d4f61b7c3368fb3e741aa3901c	1	https://github.com/rla/rdet.git
	afee76546bc60aadad03a386f5698943f61abeac	1	https://github.com/rla/rdet.git
	cbe6401d610c6710288cfdaed39ff85e6f8745ca	27	https://github.com/rla/rdet.git
1.0.2	8caf683808880c34cb3cf29f3bb0a956789557db	30	https://github.com/rla/rdet.git

Runtime non-failure checker for SWI-Prolog

Many predicates dealing with databases and external systems are non-failure. These predicates have the following properties:

• They should not fail.
• The first solution is the right solution.
• Errors are handled through exceptions.

This library attempts to provide runtime check for these conditions.


API

Use directive rdet/1 to annotate predicates that are supposed to be deterministic:

:- rdet(somepred/arity).

When annotated predicate call fails, an error is thrown:

error(goal_failed(PredicateIndicator), _)

Example

:- use_module(library(rdet)).

:- rdet(insert_sort/2).
:- rdet(i_sort/3).
:- rdet(insert/3).

insert_sort(List, Sorted):-
    i_sort(List, [], Sorted).

i_sort([], Acc, Acc).
i_sort([H|T], Acc, Sorted):-
    insert(H,Acc,NAcc),
    i_sort(T,NAcc,Sorted).

insert(X,[Y|T],[Y|NT]):-
    X>Y,
    insert(X,T,NT).

insert(X,[Y|T],[X,Y|T]):-
    X=<Y.

insert(X,[a],[X]).

Running the sorting procedure will throw an error (the last clause of insert/3 is intentionally made to fail with numbers):

?- insert_sort([2,4,1,3], Sorted).
ERROR: Unhandled exception: Goal insert/3 failed.

How does it work?

The library uses SWI-Prolog built-in predicate wrap_predicate to insert necessary checks.

Previous version of this library was using goal expansion.

Debugging

Enable rdet debug statements (before loading code to be enhanced):

?- debug(rdet).
Warning: rdet: no matching debug topic (yet)
true.

?- [insert].
% rdet: adding goal: user:insert_sort/2
% rdet: adding goal: user:i_sort/3
% rdet: adding goal: user:insert/3
true.

Module named user?

Module named user usually contains the code that is not explicitly put into a module.

Why not a static system?

Good luck building a static analysis system that includes the following:

• Instantiatedness (unbound, ground, partial)
• Type information (list vs. atom, higher order types)
• Module system support
• Supports goal_expansion and other extensions
• Higher order calls (maplist/call/etc)
• Static exceptions
• Different determinism modes: det/semidet/nondet/comitted choice
• Determinism dependence on all previous

And has all of this optional: you can combine your code easily with 3rd party untyped/unmoded libraries.

Installation

To install as a package:

pack_install(rdet).

It requires a recent SWI-Prolog version 8.x or newer.

Running tests

In the package root, insert into swipl:

[tests/tests].
run_tests.

Or if you cloned the repo:

make test

Bug reports/feature requests

Please send bug reports/feature request through the GitHub project page.

License

The MIT license. See the LICENSE file.

Contents of pack "rdet"

Pack contains 17 files holding a total of 9.9K bytes.