package org.simantics.scl.compiler.elaboration.java;

import org.simantics.scl.compiler.common.exceptions.InternalCompilerError;
import org.simantics.scl.compiler.constants.FunctionValue;
import org.simantics.scl.compiler.internal.codegen.references.Val;
import org.simantics.scl.compiler.internal.codegen.types.BTypes;
import org.simantics.scl.compiler.internal.codegen.utils.MethodBuilder;
import org.simantics.scl.compiler.types.TVar;
import org.simantics.scl.compiler.types.Type;
import org.simantics.scl.compiler.types.Types;
import org.simantics.scl.compiler.types.exceptions.MatchException;
import org.simantics.scl.compiler.types.kinds.Kinds;

public class ApplyUnit extends FunctionValue {
    
    private static final TVar A = Types.var(Kinds.STAR);
    private static final TVar E = Types.var(Kinds.EFFECT);
    
    public static final ApplyUnit INSTANCE = new ApplyUnit();
    
    private ApplyUnit() {
        super(new TVar[] {A}, E, A, Types.functionE(Types.PUNIT, E, A));
    }

    @Override
    public Type applyExact(MethodBuilder mb, Val[] parameters) {
        parameters[0].push(mb);
        mb.pushTuple0();
        mb.genericApply(1);
        try {
            return BTypes.matchFunction(parameters[0].getType(), 1)[1];
        } catch (MatchException e) {
            throw new InternalCompilerError();
        }   
    }
    
    @Override
    public String toString() {
        return "applyUnit";
    }

}