Function newBoundsAnalyzer

analysis/validation.go:428–487

(programInfo *ProgramInfo, nameTrie symbols.NameTrie, initialFacts []ast.Atom, rulesMap map[ast.PredicateSym][]ast.Clause)

}

func newBoundsAnalyzer(programInfo *ProgramInfo, nameTrie symbols.NameTrie, initialFacts []ast.Atom, rulesMap map[ast.PredicateSym][]ast.Clause) (*BoundsAnalyzer, error) {
	var err error
	relTypeMap := make(map[ast.PredicateSym]ast.BaseTerm)

	initialFactTypes := make(map[ast.PredicateSym]map[uint64]ast.BaseTerm)
	for _, f := range initialFacts {
		// From a unit clause (initial fact) `foo(2, 'a')` we
		// derive an "observation" [/int /string].
		observation := make([]ast.BaseTerm, len(f.Args))
		for i, arg := range f.Args {
			observation[i] = boundOfArg(arg, nil, nameTrie)
		}
		relType := symbols.NewRelType(observation...)
		m, ok := initialFactTypes[f.Predicate]
		if !ok {
			m = make(map[uint64]ast.BaseTerm)
			initialFactTypes[f.Predicate] = m
		}
		m[relType.Hash()] = relType
	}

	// We gather all relation types.
	initialFactMap := make(map[ast.PredicateSym]ast.BaseTerm, len(initialFactTypes))
	for pred, relTypeMap := range initialFactTypes {
		relTypes := make([]ast.BaseTerm, 0, len(relTypeMap))
		for _, relType := range relTypeMap {
			relTypes = append(relTypes, relType)
		}
		if len(relTypes) == 1 {
			initialFactMap[pred] = relTypes[0]
		} else {
			initialFactMap[pred] = symbols.NewUnionType(relTypes...)
		}
	}

	for _, decl := range programInfo.Decls {
		if decl.IsSynthetic() && !decl.IsExtensional() {
			continue
		}
		// Populate relTypes with type info from declarations.
		// For intensional predicates, we include only user-supplied declaration.
		// For extensional predicates, we include declarations whether or not they
		// are synthetic.
		pred := decl.DeclaredAtom.Predicate
		relTypeMap[pred], err = symbols.RelTypeExprFromDecl(*programInfo.Decls[pred])
		if err != nil {
			return nil, err
		}
	}

	// Populate relTypes with all builtin relation types.
	for pred, relTypeExpr := range symbols.BuiltinRelations {
		relTypeMap[pred] = relTypeExpr
	}

	visiting := make(map[ast.PredicateSym]bool)
	return &BoundsAnalyzer{
		programInfo, nameTrie, rulesMap, relTypeMap, initialFactMap,