Added clause hooks for CONSTRUCT statement.

bql/grammar/grammar.go

@@ -918,7 +918,7 @@ func SemanticBQL() *Grammar {
 	}
 	setElementHook(semanticBQL, varSymbols, semantic.VarAccumulatorHook(), nil)
 
-	// Collect and valiadate group by bindinds.
+	// Collect and validate group by bindings.
 	grpSymbols := []semantic.Symbol{"GROUP_BY", "GROUP_BY_BINDINGS"}
 	setElementHook(semanticBQL, grpSymbols, semantic.GroupByBindings(), nil)
 	setClauseHook(semanticBQL, []semantic.Symbol{"GROUP_BY"}, nil, semantic.GroupByBindingsChecker())
@@ -952,5 +952,12 @@ func SemanticBQL() *Grammar {
 		})
 	setClauseHook(semanticBQL, []semantic.Symbol{"START"}, nil, semantic.GroupByBindingsChecker())
 
+	// CONSTRUCT clause semantic hooks.
+	setClauseHook(semanticBQL, []semantic.Symbol{"CONSTRUCT"}, nil, semantic.TypeBindingClauseHook(semantic.Construct))
+	setClauseHook(semanticBQL, []semantic.Symbol{"CONSTRUCT_FACTS"}, semantic.InitWorkingConstructClauseHook(), nil)
+	constructTriplesSymbols := []semantic.Symbol{"CONSTRUCT_TRIPLES", "MORE_CONSTRUCT_TRIPLES"}
+	setClauseHook(semanticBQL, constructTriplesSymbols, semantic.NextWorkingConstructClauseHook(), semantic.NextWorkingConstructClauseHook())
+
+
 	return semanticBQL
 }

bql/semantic/hooks.go

@@ -140,6 +140,16 @@ func CollectGlobalBounds() ElementHook {
 	return collectGlobalBounds()
 }
 
+// InitWorkingConstructClauseHook returns the singleton for clause accumulation within the construct statement.
+func InitWorkingConstructClauseHook() ClauseHook {
+	return InitWorkingConstructClause()
+}
+
+// NextWorkingConstructClauseHook returns the singleton for clause accumulation within the construct statement.
+func NextWorkingConstructClauseHook() ClauseHook {
+	return NextWorkingConstructClause()
+}
+
 // TypeBindingClauseHook returns a ClauseHook that sets the binding type.
 func TypeBindingClauseHook(t StatementType) ClauseHook {
 	var f ClauseHook
@@ -567,7 +577,7 @@ func whereObjectClause() ElementHook {
 	return f
 }
 
-// whereObjectClause returns an element hook that updates the object
+// varAccumulator returns an element hook that updates the object
 // modifiers on the working graph clause.
 func varAccumulator() ElementHook {
 	var (
@@ -862,3 +872,26 @@ func collectGlobalBounds() ElementHook {
 	}
 	return f
 }
+
+// InitWorkingConstructClause returns a clause hook to initialize a new working
+// construct clause.
+func InitWorkingConstructClause() ClauseHook {
+	var f ClauseHook
+	f = func(s *Statement, _ Symbol) (ClauseHook, error) {
+		s.ResetWorkingConstructClause()
+		return f, nil
+	}
+	return f
+}
+
+
+// NextWorkingConstructClause returns a clause hook to close the current working
+// construct clause and start a new working construct clause.
+func NextWorkingConstructClause() ClauseHook {
+	var f ClauseHook
+	f = func(s *Statement, _ Symbol) (ClauseHook, error) {
+		s.AddWorkingConstructClause()
+		return f, nil
+	}
+	return f
+}

bql/semantic/hooks_test.go

@@ -136,7 +136,7 @@ func TestTypeBindingClauseHook(t *testing.T) {
 	st := &Statement{}
 	f(st, Symbol("FOO"))
 	if got, want := st.Type(), Insert; got != want {
-		t.Errorf("semantic.TypeBidingHook failed to set the right type; got %s, want %s", got, want)
+		t.Errorf("semantic.TypeBindingHook failed to set the right type; got %s, want %s", got, want)
 	}
 }
 
@@ -153,9 +153,14 @@ func TestWhereWorkingClauseHook(t *testing.T) {
 	f := whereNextWorkingClause()
 	st := &Statement{}
 	st.ResetWorkingGraphClause()
+	wcs := st.WorkingClause()
+	wcs.SBinding = "?a"
 	f(st, Symbol("FOO"))
+	wcs = st.WorkingClause()
+	wcs.SBinding = "?b"
 	f(st, Symbol("FOO"))
-	if got, want := len(st.GraphPatternClauses()), 0; got != want {
+
+	if got, want := len(st.GraphPatternClauses()), 2; got != want {
 		t.Errorf("semantic.whereNextWorkingClause should have returned two clauses for statement %v; got %d, want %d", st, got, want)
 	}
 }
@@ -1169,7 +1174,7 @@ func TestBindingsGraphChecker(t *testing.T) {
 		want bool
 	}{
 		{
-			id: "missing biding",
+			id: "missing binding",
 			s: &Statement{
 				pattern: []*GraphClause{
 					{},
@@ -1199,7 +1204,7 @@ func TestBindingsGraphChecker(t *testing.T) {
 			want: false,
 		},
 		{
-			id: "all bidings available",
+			id: "all bindings available",
 			s: &Statement{
 				pattern: []*GraphClause{
 					{},
@@ -1913,3 +1918,27 @@ func TestCollectGlobalBounds(t *testing.T) {
 		}
 	}
 }
+
+func TestInitWorkingConstructClauseHook(t *testing.T) {
+	f := InitWorkingConstructClause()
+	st := &Statement{}
+	f(st, Symbol("FOO"))
+	if st.WorkingConstructClause() == nil {
+		t.Errorf("semantic.InitConstructWorkingClause should have returned a valid working clause for statement %v", st)
+	}
+}
+
+func TestNextWorkingConstructClauseHook(t *testing.T) {
+	f := NextWorkingConstructClause()
+	st := &Statement{}
+	st.ResetWorkingConstructClause()
+	wcs := st.WorkingConstructClause()
+	wcs.SBinding = "?a"
+	f(st, Symbol("FOO"))
+	wcs = st.WorkingConstructClause()
+	wcs.SBinding = "?b"
+	f(st, Symbol("FOO"))
+	if got, want := len(st.ConstructClauses()), 2; got != want {
+		t.Errorf("semantic.NextConstructWorkingClause should have returned two clauses for statement %v; got %d, want %d", st, got, want)
+	}
+}

bql/semantic/semantic.go

@@ -692,11 +692,20 @@ func (s *Statement) GlobalLookupOptions() *storage.LookupOptions {
 	return &lo
 }
 
+// ConstructClauses returns the list of construct clauses in the statement.
+func (s *Statement) ConstructClauses() []*ConstructClause {
+	return s.constructClauses
+}
+
 // ResetWorkingConstructClause resets the current working construct clause.
 func (s *Statement) ResetWorkingConstructClause() {
-		s.workingConstructClause = &ConstructClause{}
+	s.workingConstructClause = &ConstructClause{}
 }
 
+// WorkingConstructClause returns the current working clause.
+func (s *Statement) WorkingConstructClause() *ConstructClause {
+	return s.workingConstructClause
+}
 
 // AddWorkingConstructClause adds the current working construct clause to the set
 // of construct clauses that form the construct statement.