1 files changed, 101 insertions, 0 deletions
diff --git a/JPratt/src/main/java/com/ashardalon/pratt/blocks/RepeatingParseBlock.java b/JPratt/src/main/java/com/ashardalon/pratt/blocks/RepeatingParseBlock.java
new file mode 100644
index 0000000..25827b4
--- /dev/null
+++ b/JPratt/src/main/java/com/ashardalon/pratt/blocks/RepeatingParseBlock.java
@@ -0,0 +1,101 @@
+package com.ashardalon.pratt.blocks;
+
+import java.util.function.UnaryOperator;
+
+import com.ashardalon.pratt.ParserContext;
+import com.ashardalon.pratt.commands.CommandResult;
+import com.ashardalon.pratt.commands.CommandResult.Status;
+import com.ashardalon.pratt.tokens.Token;
+
+import bjc.data.Tree;
+import bjc.data.SimpleTree;
+import bjc.utils.parserutils.ParserException;
+
+/**
+ * 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 final ParseBlock<K, V, C> innerBlock;
+
+	private final K delim;
+	private final K term;
+
+	private final UnaryOperator<C> onDelim;
+
+	private final 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(final ParseBlock<K, V, C> inner, final K delimiter, final K terminator,
+			final Token<K, V> marker, final 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 CommandResult<K, V> parse(final ParserContext<K, V, C> ctx) throws ParserException {
+		final Tree<Token<K, V>> ret = new SimpleTree<>(mark);
+
+		Token<K, V> tok = ctx.tokens.current();
+
+		while(!tok.getKey().equals(term)) {
+			final CommandResult<K,V> resKid = innerBlock.parse(ctx);
+			if (resKid.status != Status.SUCCESS) return resKid;
+			Tree<Token<K, V>> kid = resKid.success();
+			ret.addChild(kid);
+
+			tok = ctx.tokens.current();
+
+			ctx.tokens.expect(delim, term);
+
+			if(onDelim != null) {
+				ctx.state = onDelim.apply(ctx.state);
+			}
+		}
+
+		return CommandResult.success(ret);
+	}
+
+}