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package bjc.pratt.commands.impls;
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;
/**
* A command that denests a input tree.
*
* Useful for processing the result of passing a complex parse group to a
* 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 DenestingCommand<K, V, C> extends AbstractInitialCommand<K, V, C> {
private final InitialCommand<K, V, C> wrapped;
/**
* Create a new transforming initial command.
*
* @param internal
* The initial command to delegate to.
*/
public DenestingCommand(final InitialCommand<K, V, C> internal) {
wrapped = internal;
}
@Override
protected CommandResult<K, V> intNullDenotation(final Token<K, V> operator, final ParserContext<K, V, C> ctx)
throws ParserException {
CommandResult<K, V> res = wrapped.denote(operator, ctx);
if (res.status != Status.SUCCESS) return res;
return CommandResult.success(res.success().getChild(0));
}
}
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