/*
* Copyright 2003-2011 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jetbrains.mps.newTypesystem.relations;
import jetbrains.mps.newTypesystem.SubtypingUtil;
import jetbrains.mps.newTypesystem.TypesUtil;
import jetbrains.mps.newTypesystem.state.State;
import jetbrains.mps.newTypesystem.state.blocks.RelationBlock;
import jetbrains.mps.newTypesystem.state.blocks.RelationKind;
import org.jetbrains.mps.openapi.model.SNode;
import jetbrains.mps.typesystem.inference.EquationInfo;
import jetbrains.mps.typesystemEngine.util.LatticeUtil;
import java.util.*;
public class SubTypingRelation extends AbstractRelation {
@Override
public boolean accept(RelationKind kind) {
return !kind.isComparable();
}
@Override
public boolean solve(SNode node, Set<SNode> leftTypes, Set<SNode> rightTypes, State state, Map<SNode, RelationBlock> typesToBlocks) {
SNode result = null;
EquationInfo info = null;
if (!leftTypes.isEmpty()) {
final LinkedList<SNode> leftTypesList = new LinkedList<SNode>();
for (SNode lt: leftTypes) {
if (LatticeUtil.isMeet(lt)) {
lt = TypesUtil.cleanupMeet(lt);
}
leftTypesList.add(lt);
}
result = SubtypingUtil.createLeastCommonSupertype(leftTypesList, state.getTypeCheckingContext());
if (LatticeUtil.isMeet(result)) {
result = TypesUtil.cleanupMeet(result);
}
RelationBlock block = typesToBlocks.get(result);
info = (block != null) ? block.getEquationInfo() : typesToBlocks.get(leftTypes.iterator().next()).getEquationInfo();
} else if (!rightTypes.isEmpty()) {
result = createMeet(rightTypes);
RelationBlock block = typesToBlocks.get(result);
info = (block != null) ? block.getEquationInfo() : typesToBlocks.get(rightTypes.iterator().next()).getEquationInfo();
}
if (TypesUtil.isVariable(result) && TypesUtil.isVariable(node) && result.getName().equals(node.getName())) return false;
return result != null && state.addEquation(node, result, info);
}
private SNode createMeet(Set<SNode> rightTypes) {
List<SNode> types = new LinkedList<SNode>(rightTypes);
if (types.size() > 1) {
types = SubtypingUtil.eliminateSuperTypes(types);
}
return LatticeUtil.meetNodes(new LinkedHashSet<SNode>(types));
}
}