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package bjc.pratt.commands.impls;
import java.util.function.UnaryOperator;
import bjc.pratt.ParserContext;
import bjc.pratt.commands.AbstractInitialCommand;
import bjc.pratt.commands.CommandResult;
import bjc.pratt.commands.CommandResult.Status;
import bjc.pratt.commands.InitialCommand;
import bjc.pratt.tokens.Token;
import bjc.data.Tree;
import bjc.utils.parserutils.ParserException;
/**
* An initial command that transforms the result of another command.
*
* @author bjculkin
*
* @param <K>
* The key type of the tokens.
*
* @param <V>
* The value type of the tokens.
*
* @param <C>
* The state type of the parser.
*/
public class TransformingInitialCommand<K, V, C> extends AbstractInitialCommand<K, V, C> {
private final InitialCommand<K, V, C> internl;
private final UnaryOperator<Tree<Token<K, V>>> transfrm;
/**
* Create a new transforming initial command.
*
* @param internal
* The initial command to delegate to.
*
* @param transform
* The transform to apply to the returned tree.
*/
public TransformingInitialCommand(final InitialCommand<K, V, C> internal,
final UnaryOperator<Tree<Token<K, V>>> transform) {
super();
internl = internal;
transfrm = transform;
}
@Override
protected CommandResult<K, V> intNullDenotation(final Token<K, V> operator, final ParserContext<K, V, C> ctx)
throws ParserException {
CommandResult<K,V> result = internl.denote(operator, ctx);
if (result.status != Status.SUCCESS) return result;
return CommandResult.success(transfrm.apply(result.success()));
}
}
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