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package bjc.pratt.commands.impls;
import bjc.data.SimpleTree;
import bjc.data.Tree;
import bjc.pratt.ParserContext;
import bjc.pratt.commands.CommandResult;
import bjc.pratt.commands.InitialCommand;
import bjc.pratt.commands.CommandResult.Status;
import bjc.pratt.tokens.Token;
import bjc.utils.parserutils.ParserException;
/**
* Represents a 'panfix' command, one where the operator is repeated prefix, infix and postfix.
* @author bjcul
*
* @param <K> The key type of the token
* @param <V> The value type of the token
* @param <C> The context type of the parser
*/
public final class PanfixCommand<K, V, C> implements InitialCommand<K, V, C> {
private final Token<K, V> marker;
private final K term;
private final int precedence;
/**
* Create a new panfix command.
*
* @param marker The marker token.
* @param term The value to use as the root of the result-tree
* @param precedence The precedence for this command
*/
public PanfixCommand(Token<K, V> marker, K term, int precedence) {
this.marker = marker;
this.term = term;
this.precedence = precedence;
}
@Override
public CommandResult<K, V> denote(Token<K, V> operator, ParserContext<K, V, C> ctx) throws ParserException {
CommandResult<K,V> resLeftSide = ctx.parse.parseExpression(precedence + 1, ctx.tokens, ctx.state, false);
if (resLeftSide.status != Status.SUCCESS) return resLeftSide;
Tree<Token<K, V>> leftSide = resLeftSide.success();
ctx.tokens.expect(term);
ctx.tokens.next();
CommandResult<K, V> resRightSide = ctx.parse.parseExpression(precedence + 1, ctx.tokens, ctx.state, false);
if (resLeftSide.status != Status.SUCCESS) return resRightSide;
Tree<Token<K,V>> rightSide = resRightSide.success();
ctx.tokens.expect(term);
ctx.tokens.next();
return CommandResult.success(new SimpleTree<>(marker, leftSide, rightSide));
}
}
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