Implement Pratt parser.

1 files changed, 44 insertions, 0 deletions

diff --git a/BJC-Utils2/src/main/java/bjc/utils/parserutils/pratt/StringTokenStream.java b/BJC-Utils2/src/main/java/bjc/utils/parserutils/pratt/StringTokenStream.java
new file mode 100644
index 0000000..8caeef9
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/parserutils/pratt/StringTokenStream.java
@@ -0,0 +1,44 @@
+package bjc.utils.parserutils.pratt;
+
+import java.util.Iterator;
+
+/**
+ * Simple implementation of token stream for strings.
+ * 
+ * The terminal token here is represented by a token with type '(end)' and null
+ * value.
+ * 
+ * @author EVE
+ *
+ */
+public class StringTokenStream implements TokenStream<String, String> {
+	private Iterator<Token<String, String>> iter;
+
+	private Token<String, String> curr;
+
+	/**
+	 * Create a new token stream from a iterator.
+	 * 
+	 * @param itr
+	 *                The iterator to use.
+	 * 
+	 */
+	public StringTokenStream(Iterator<Token<String, String>> itr) {
+		iter = itr;
+
+	}
+
+	@Override
+	public Token<String, String> current() {
+		return curr;
+	}
+
+	@Override
+	public void next() {
+		if(iter.hasNext()) {
+			curr = iter.next();
+		} else {
+			curr = new StringToken("(end)", null);
+		}
+	}
+}