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# engines - interactors

This example requires support for both threads and coroutining. Currently it
runs on ECLiPSe and SWI-Prolog. It should run also on XSB and YAP if and when
these systems bugs with coroutining and/or threads get fixed.

This folder contains examples of interactors implemented using threaded engines.
Interactors are described in the paper:

```bibtex
@article{Tarau2000,
	author="Paul Tarau",
	title="Architecture and Implementation Aspects of the Lean Prolog System",
	url="http://www.cse.unt.edu/~tarau/research/LeanProlog/ArchitectureOfLeanProlog.pdf"
}
```

Print Logtalk, Prolog backend, and kernel versions (if running as a notebook):

```logtalk
%versions
```

Load the example:

```logtalk
logtalk_load(interactors(loader)).
```

<!--
true.
-->

Get natural numbers in increasing order:

```logtalk
interactors::natural(N).
```

<!--
N = 1.
-->

```logtalk
interactors::natural(N).
```

<!--
N = 2.
-->

```logtalk
interactors::natural(N).
```

<!--
N = 3.
-->

Get prime numbers in increasing order:

```logtalk
interactors::prime(P).
```

<!--
N = 2.
-->

```logtalk
interactors::prime(P).
```

<!--
N = 3.
-->

```logtalk
interactors::prime(P).
```

<!--
N = 5.
-->

Interactor with goal injection:

```logtalk
interactors<<sums(S).
```

<!--
S =  (0->2).
-->

```logtalk
interactors<<sums(S).
```

<!--
S =  (2->7).
-->

```logtalk
interactors<<sums(S).
```

<!--
S =  (7->9).
-->
