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Diffstat (limited to 'JPratt/src/main/java/bjc/pratt/blocks/GrammarParseBlock.java')
| -rw-r--r-- | JPratt/src/main/java/bjc/pratt/blocks/GrammarParseBlock.java | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/JPratt/src/main/java/bjc/pratt/blocks/GrammarParseBlock.java b/JPratt/src/main/java/bjc/pratt/blocks/GrammarParseBlock.java new file mode 100644 index 0000000..459f83d --- /dev/null +++ b/JPratt/src/main/java/bjc/pratt/blocks/GrammarParseBlock.java @@ -0,0 +1,81 @@ +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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