46 lines
706 B
Plaintext
46 lines
706 B
Plaintext
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% simple example of defining an operator local to a source file
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:- op(200, xfx, edge). % global operator, visible within all
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% entities defined in this source file
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:- object(graph).
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:- public(path/3).
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:- public((edge)/2).
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path(Start, End, [Start, End]) :-
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::(Start edge End).
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path(Start, End, [Start| Path]) :-
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::(Start edge Node),
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path(Node, End, Path).
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:- end_object.
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:- object(graph1,
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extends(graph)).
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a edge b.
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a edge c.
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b edge d.
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c edge d.
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:- end_object.
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:- object(graph2,
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extends(graph)).
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v1 edge v2.
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v1 edge v3.
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v2 edge v4.
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v3 edge v4.
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:- end_object.
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:- op(0, xfx, edge). % "undefine" the operator, effectively
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% making it local to this source file
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