Move Pratt Parser to new project

1 files changed, 73 insertions, 0 deletions

diff --git a/JPratt/src/main/java/bjc/utils/parserutils/pratt/commands/ChainCommand.java b/JPratt/src/main/java/bjc/utils/parserutils/pratt/commands/ChainCommand.java
new file mode 100644
index 0000000..1324586
--- /dev/null
+++ b/JPratt/src/main/java/bjc/utils/parserutils/pratt/commands/ChainCommand.java
@@ -0,0 +1,73 @@
+package bjc.utils.parserutils.pratt.commands;
+
+import bjc.utils.data.ITree;
+import bjc.utils.data.Tree;
+import bjc.utils.parserutils.ParserException;
+import bjc.utils.parserutils.pratt.ParserContext;
+import bjc.utils.parserutils.pratt.Token;
+
+import java.util.Set;
+
+/**
+ * Create a new chained operator.
+ * 
+ * @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 ChainCommand<K, V, C> extends BinaryPostCommand<K, V, C> {
+	private Set<K> chainWith;
+
+	private Token<K, V> chain;
+
+	/**
+	 * Create a new chained operator.
+	 * 
+	 * @param precedence
+	 *                The precedence of this operator.
+	 * 
+	 * @param chainSet
+	 *                The operators to chain with.
+	 * 
+	 * @param chainMarker
+	 *                The token to use as the node in the AST.
+	 */
+	public ChainCommand(int precedence, Set<K> chainSet, Token<K, V> chainMarker) {
+		super(precedence);
+
+		chainWith = chainSet;
+		chain = chainMarker;
+	}
+
+	@Override
+	public ITree<Token<K, V>> denote(ITree<Token<K, V>> operand, Token<K, V> operator, ParserContext<K, V, C> ctx)
+			throws ParserException {
+		ITree<Token<K, V>> tree = ctx.parse.parseExpression(1 + leftBinding(), ctx.tokens, ctx.state, false);
+
+		ITree<Token<K, V>> res = new Tree<>(operator, operand, tree);
+
+		if (chainWith.contains(ctx.tokens.current().getKey())) {
+			Token<K, V> tok = ctx.tokens.current();
+			ctx.tokens.next();
+
+			ITree<Token<K, V>> other = denote(tree, tok,
+					new ParserContext<>(ctx.tokens, ctx.parse, ctx.state));
+
+			return new Tree<>(chain, res, other);
+		} else {
+			return res;
+		}
+	}
+
+	@Override
+	public int nextBinding() {
+		return leftBinding() - 1;
+	}
+}
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