(program Program)
| 41 | } |
| 42 | |
| 43 | func makeDepGraph(program Program) depGraph { |
| 44 | dep := make(depGraph) |
| 45 | for _, rule := range program.Rules { |
| 46 | s := rule.Head.Predicate |
| 47 | dep.initNode(s) |
| 48 | for _, premise := range rule.Premises { |
| 49 | switch p := premise.(type) { |
| 50 | case ast.Atom: |
| 51 | if _, ok := builtin.Predicates[p.Predicate]; ok { |
| 52 | continue |
| 53 | } |
| 54 | if _, ok := program.EdbPredicates[p.Predicate]; !ok { |
| 55 | if rule.Transform == nil || rule.Transform.IsLetTransform() { |
| 56 | dep.addEdge(s, p.Predicate, false) |
| 57 | } else { |
| 58 | // Recursion through a do-transform is not permitted. |
| 59 | // We treat this as if it was a negation. |
| 60 | dep.addEdge(s, p.Predicate, true) |
| 61 | } |
| 62 | } |
| 63 | case ast.NegAtom: |
| 64 | if _, ok := program.EdbPredicates[p.Atom.Predicate]; !ok { |
| 65 | dep.addEdge(s, p.Atom.Predicate, true) |
| 66 | } |
| 67 | } |
| 68 | } |
| 69 | } |
| 70 | return dep |
| 71 | } |
| 72 | |
| 73 | // Stratify checks whether a program can be stratified. It returns strongly-connected components |
| 74 | // and a map from predicate to stratum in the affirmative case, an error otherwise. |
no test coverage detected