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package com.ashardalon.pratt.commands.impls;
import bjc.data.Tree;
import com.ashardalon.pratt.ParserContext;
import com.ashardalon.pratt.blocks.ParseBlock;
import com.ashardalon.pratt.commands.AbstractInitialCommand;
import com.ashardalon.pratt.commands.CommandResult;
import com.ashardalon.pratt.commands.CommandResult.Status;
import com.ashardalon.pratt.tokens.Token;
import bjc.data.SimpleTree;
import bjc.utils.parserutils.ParserException;
/**
* A prefix ternary operator, like an if/then/else group.
*
* @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 PreTernaryCommand<K, V, C> extends AbstractInitialCommand<K, V, C> {
private final Token<K, V> trm;
private final ParseBlock<K, V, C> condBlock;
private final ParseBlock<K, V, C> opblock1;
private final ParseBlock<K, V, C> opblock2;
/**
* Create a new ternary statement.
*
* @param cond
* The block for handling the condition.
*
* @param op1
* The block for handling the first operator.
*
* @param op2
* The block for handling the second operator.
*
* @param term
* The token to use as the node for the AST.
*/
public PreTernaryCommand(final ParseBlock<K, V, C> cond, final ParseBlock<K, V, C> op1,
final ParseBlock<K, V, C> op2, final Token<K, V> term) {
super();
if(cond == null)
throw new NullPointerException("Cond block must not be null");
else if(op1 == null)
throw new NullPointerException("Op block #1 must not be null");
else if(op2 == null) throw new NullPointerException("Op block #2 must not be null");
condBlock = cond;
opblock1 = op1;
opblock2 = op2;
trm = term;
}
@Override
protected CommandResult<K, V> intNullDenotation(final Token<K, V> operator, final ParserContext<K, V, C> ctx)
throws ParserException {
final CommandResult<K,V> condRes = condBlock.parse(ctx);
if (condRes.status != Status.SUCCESS) return condRes;
Tree<Token<K, V>> cond = condRes.success();
final CommandResult<K,V> op1Res = opblock1.parse(ctx);
if (op1Res.status != Status.SUCCESS) return op1Res;
Tree<Token<K, V>> op1 = op1Res.success();
final CommandResult<K,V> op2Res = opblock2.parse(ctx);
if (op2Res.status != Status.SUCCESS) return op2Res;
Tree<Token<K, V>> op2 = op2Res.success();
return CommandResult.success(new SimpleTree<>(trm, cond, op1, op2));
}
}
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