mapl-com (maude prolog communication)

This is a simple example of a maude program querying a prolog server for facts.

Running the example

First start the prolog server:

• $ swipl
• ?- [pl_server].
• ?- create_server(3050).

Then run the maude client:

• $ maude
• Maude> in family.maude .
• Maude> erew {test(3050)} .
• Maude> erew {test2(3050)} .
• Maude> erew {test3(3050)} .

Where test is the specification: <> < aClient : Client | none > male(“thomas”) female(“anna”) relationshipStatus(“thomas”, single) relationshipStatus(“anna”, single)

test2 is: <> < aClient : Client | none > male(“thomas”) female(“anna”) female(“anna”) relationshipStatus(“thomas”, single) relationshipStatus(“anna”, single) relationshipStatus(“anna”, single)

test3 is: <> < aClient : Client | none > male(“thomas”) female(“anna”) female(“anna”) female(“maria”) relationshipStatus(“thomas”, single) relationshipStatus(“anna”, single) relationshipStatus(“anna”, single) relationshipStatus(“maria”, single)

Example description

The point of the examples is to see if anyone will get engaged. The maude program has a conditional rewrite rule for engagements where the people getting engaged can’t be siblings and none of them can be the parent of the other. Who’s the parent of who is not known to maude, but is stored as facts on the prolog server:

• parent(thomas, anna).
• parent(maria, anna).
• parent(rolf, maria).

Maude has to query for these facts during execution to figure out if anyone can get engaged.