hydra.lib.lists.Reverse Maven / Gradle / Ivy

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package hydra.lib.lists;

import hydra.Flows;
import hydra.compute.Flow;
import hydra.core.Name;
import hydra.core.Term;
import hydra.core.Type;
import hydra.dsl.Expect;
import hydra.dsl.Terms;
import hydra.graph.Graph;
import hydra.tools.PrimitiveFunction;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.function.Function;

import static hydra.dsl.Types.function;
import static hydra.dsl.Types.lambda;
import static hydra.dsl.Types.list;

public class Reverse extends PrimitiveFunction {
    public static final Name NAME = new Name("hydra/lib/lists.reverse");

    public Name name() {
        return NAME;
    }

    @Override
    public Type type() {
        return lambda("a", function(list("a"), list("a")));
    }

    @Override
    protected Function>, Flow, Term>> implementation() {
        return args -> Flows.map(
                Expect.list(Flows::pure, args.get(0)), l -> Terms.list(Reverse.apply(l)));
    }

    /**
     * Apply the function to the single argument.
     */
    public static  List apply(List list) {
        List newList = new ArrayList<>();
        newList.addAll(list);
        Collections.reverse(list);
        return newList;
    }
}