以图形表示形式获取 Prolog 查询结果

Question

我有以下代码：

edge(a,e).
edge(e,d).
edge(d,c).
edge(c,b).
edge(b,a).
edge(d,a).
edge(e,c).
edge(f,b).
graph(Graph):-findall(A-B, edge(A,B), L),
    findall(B-A, edge(A,B), L1),
    append(L, L1, Graph).

执行查询以获得结果图后，我得到以下信息：

?-rbacGraph(Graph);true.
Graph=[a-e,b-a,c-b,d-a,d-c,e-c,e-d,f-b,a-b,a-d,b-c,b-f,c-d,c-e,d-e,e-a].

我只想问这个，有什么方法可以从 Prolog 中获取或将结果转换为图形表示（获取节点和连接边）？

Answer 1

您可以考虑将此 'program' 生成的输出粘贴到以下 HTML5 片段（由 cytoscape.js 提供）：

graph_so :-
    setof(N, M^(edge(N,M);edge(M,N)), Ns),
    maplist([N] >> format('{data:{id:"~w"}},~n', [N]), Ns),
    forall(edge(S,T), format('{data:{id:"~w-~w",source:"~w",target:"~w"}},~n', [S,T,S,T])).

edge(a,e).
edge(e,d).
edge(d,c).
edge(c,b).
edge(b,a).
edge(d,a).
edge(e,c).
edge(f,b).

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/cytoscape/2.7.16/cytoscape.min.js"></script>
</head>
<div id='cy'></div>
<style>
#cy {
  width: 500px;
  height: 500px;
}
</style>
<script>
(function() {
    
    var elements = [
        // generated by Prolog
        {data:{id:"a"}},
        {data:{id:"b"}},
        {data:{id:"c"}},
        {data:{id:"d"}},
        {data:{id:"e"}},
        {data:{id:"f"}},
        {data:{id:"a-e",source:"a",target:"e"}},
        {data:{id:"e-d",source:"e",target:"d"}},
        {data:{id:"d-c",source:"d",target:"c"}},
        {data:{id:"c-b",source:"c",target:"b"}},
        {data:{id:"b-a",source:"b",target:"a"}},
        {data:{id:"d-a",source:"d",target:"a"}},
        {data:{id:"e-c",source:"e",target:"c"}},
        {data:{id:"f-b",source:"f",target:"b"}},                
    ];
    
    var cy = cytoscape({
        container: document.getElementById('cy'),
        elements: elements,
        style: [
            {   selector: 'node',
                style: {
                    'background-color': '#666',
                    'label': 'data(id)'
                }
            },
            {   selector: 'edge',
                style: {
                    'target-arrow-shape': 'triangle',
                    'width': 3,
                    'line-color': '#ddd',
                    'target-arrow-color': '#ddd',
                    'curve-style': 'bezier'
                }
            }
        ],
    })

    var layout = cy.makeLayout({ name: 'cose' });
    layout.run();
})()
</script>
</html>

或者这个更有效的模式（从 Prolog 的角度来看），它生成一个有向图，就像你从你的原始代码中得到的那样：

graph_opt :-
    setof(N, node_(N), Ns),
    maplist([N] >> format('{data:{id:"~w"}},~n', [N]), Ns).
node_(S) :-
    ( edge(S,T) ; edge(T,S) ),
    format('{data:{id:"~w-~w",source:"~w",target:"~w"}},~n', [S,T,S,T]).

编辑

从 HTML 代码段中删除了 jQuery 依赖项

以图形表示形式获取 Prolog 查询结果

Get Prolog query results as a graph representation

prolog

swi-prolog