Move Pratt Parser to new project

1 files changed, 96 insertions, 0 deletions

diff --git a/JPratt/src/main/java/bjc/utils/parserutils/pratt/blocks/RepeatingParseBlock.java b/JPratt/src/main/java/bjc/utils/parserutils/pratt/blocks/RepeatingParseBlock.java
new file mode 100644
index 0000000..08a4bae
--- /dev/null
+++ b/JPratt/src/main/java/bjc/utils/parserutils/pratt/blocks/RepeatingParseBlock.java
@@ -0,0 +1,96 @@
+package bjc.utils.parserutils.pratt.blocks;
+
+import java.util.function.UnaryOperator;
+
+import bjc.utils.data.ITree;
+import bjc.utils.data.Tree;
+import bjc.utils.parserutils.ParserException;
+import bjc.utils.parserutils.pratt.ParseBlock;
+import bjc.utils.parserutils.pratt.ParserContext;
+import bjc.utils.parserutils.pratt.Token;
+
+/**
+ * A parse block that can parse a sequnce of zero or more occurances of another
+ * block.
+ * 
+ * @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 RepeatingParseBlock<K, V, C> implements ParseBlock<K, V, C> {
+	private ParseBlock<K, V, C> innerBlock;
+
+	private K	delim;
+	private K	term;
+
+	private UnaryOperator<C> onDelim;
+
+	private Token<K, V> mark;
+
+	/**
+	 * Create a new repeating block.
+	 * 
+	 * @param inner
+	 *                The inner block for elements.
+	 * 
+	 * @param delimiter
+	 *                The token that delimits elements in the sequence.
+	 * 
+	 * @param terminator
+	 *                The token that terminates the sequence.
+	 * 
+	 * @param marker
+	 *                The token to use as the node in the AST.
+	 * 
+	 * @param action
+	 *                The action to apply to the state after every
+	 *                delimiter.
+	 */
+	public RepeatingParseBlock(ParseBlock<K, V, C> inner, K delimiter, K terminator, Token<K, V> marker,
+			UnaryOperator<C> action) {
+		super();
+
+		if (inner == null)
+			throw new NullPointerException("Inner block must not be null");
+		else if (delimiter == null)
+			throw new NullPointerException("Delimiter must not be null");
+		else if (terminator == null) throw new NullPointerException("Terminator must not be null");
+
+		innerBlock = inner;
+
+		delim = delimiter;
+		term = terminator;
+
+		mark = marker;
+
+		onDelim = action;
+	}
+
+	@Override
+	public ITree<Token<K, V>> parse(ParserContext<K, V, C> ctx) throws ParserException {
+		ITree<Token<K, V>> ret = new Tree<>(mark);
+
+		Token<K, V> tok = ctx.tokens.current();
+
+		while (!tok.getKey().equals(term)) {
+			ITree<Token<K, V>> kid = innerBlock.parse(ctx);
+			ret.addChild(kid);
+
+			tok = ctx.tokens.current();
+
+			ctx.tokens.expect(delim, term);
+
+			if (onDelim != null) ctx.state = onDelim.apply(ctx.state);
+		}
+
+		return ret;
+	}
+
+}