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package bjc.pratt.blocks;
import java.util.function.Function;
import bjc.pratt.ParseBlock;
import bjc.pratt.ParserContext;
import bjc.pratt.PrattParser;
import bjc.pratt.Token;
import bjc.pratt.TokenStream;
import bjc.utils.data.ITree;
import bjc.utils.funcutils.Isomorphism;
import bjc.utils.parserutils.ParserException;
/**
* A {@link ParseBlock} that parses an expression from a 'inner' grammar.
*
* @author bjculkin
*
* @param <K>
* The key type of the outer tokens.
*
* @param <V>
* The value type of the outer tokens.
*
* @param <C>
* The state type of the outer parser.
*
* @param <K2>
* The key type of the inner tokens.
*
* @param <V2>
* The value type of the inner tokens.
*
* @param <C2>
* The state type of the outer parser.
*/
public class GrammarParseBlock<K, V, C, K2, V2, C2> implements ParseBlock<K, V, C> {
private PrattParser<K2, V2, C2> inner;
private int precedence;
private boolean isStatement;
private Function<TokenStream<K, V>, TokenStream<K2, V2>> tokenTransform;
private Isomorphism<C, C2> stateTransform;
private Function<ITree<Token<K2, V2>>, ITree<Token<K, V>>> expressionTransform;
/**
* Create a new grammar parser block.
*
* @param inner
* @param precedence
* @param isStatement
* @param tokenTransform
* @param stateTransform
* @param expressionTransform
*/
public GrammarParseBlock(PrattParser<K2, V2, C2> inner, int precedence, boolean isStatement,
Function<TokenStream<K, V>, TokenStream<K2, V2>> tokenTransform,
Isomorphism<C, C2> stateTransform,
Function<ITree<Token<K2, V2>>, ITree<Token<K, V>>> expressionTransform) {
this.inner = inner;
this.precedence = precedence;
this.isStatement = isStatement;
this.tokenTransform = tokenTransform;
this.stateTransform = stateTransform;
this.expressionTransform = expressionTransform;
}
@Override
public ITree<Token<K, V>> parse(ParserContext<K, V, C> ctx) throws ParserException {
C2 newState = stateTransform.to(ctx.state);
TokenStream<K2, V2> newTokens = tokenTransform.apply(ctx.tokens);
ITree<Token<K2, V2>> expression = inner.parseExpression(precedence, newTokens, newState, isStatement);
ctx.state = stateTransform.from(newState);
return expressionTransform.apply(expression);
}
}
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