More work on parse blocks

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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