Package reorganization

4 files changed, 134 insertions, 5 deletions

diff --git a/JPratt/src/main/java/bjc/pratt/tokens/StringToken.java b/JPratt/src/main/java/bjc/pratt/tokens/StringToken.java
index 6d3c1a5..ff47667 100644
--- a/JPratt/src/main/java/bjc/pratt/tokens/StringToken.java
+++ b/JPratt/src/main/java/bjc/pratt/tokens/StringToken.java
@@ -1,7 +1,5 @@
 package bjc.pratt.tokens;
 
-import bjc.pratt.Token;
-
 /**
  * Simple token implementation for strings.
  *
diff --git a/JPratt/src/main/java/bjc/pratt/tokens/StringTokenStream.java b/JPratt/src/main/java/bjc/pratt/tokens/StringTokenStream.java
index b33dae8..07e1827 100644
--- a/JPratt/src/main/java/bjc/pratt/tokens/StringTokenStream.java
+++ b/JPratt/src/main/java/bjc/pratt/tokens/StringTokenStream.java
@@ -4,9 +4,6 @@ import static bjc.pratt.tokens.StringToken.litToken;
 
 import java.util.Iterator;
 
-import bjc.pratt.Token;
-import bjc.pratt.TokenStream;
-
 /**
  * Simple implementation of token stream for strings.
  *
diff --git a/JPratt/src/main/java/bjc/pratt/tokens/Token.java b/JPratt/src/main/java/bjc/pratt/tokens/Token.java
new file mode 100644
index 0000000..b07d2e1
--- /dev/null
+++ b/JPratt/src/main/java/bjc/pratt/tokens/Token.java
@@ -0,0 +1,30 @@
+package bjc.pratt.tokens;
+
+/**
+ * Represents a simple parsing token.
+ *
+ * @author EVE
+ *
+ * @param <K>
+ *                The key type of this token. Represents the type of the token.
+ *
+ * @param <V>
+ *                The value type of this token. Represents any additional data
+ *                for the token.
+ *
+ */
+public interface Token<K, V> {
+	/**
+	 * Get the key for this token.
+	 *
+	 * @return The key for this token
+	 */
+	K getKey();
+
+	/**
+	 * Get the value for this token.
+	 *
+	 * @return The value for this token.
+	 */
+	V getValue();
+}
diff --git a/JPratt/src/main/java/bjc/pratt/tokens/TokenStream.java b/JPratt/src/main/java/bjc/pratt/tokens/TokenStream.java
new file mode 100644
index 0000000..a5febcc
--- /dev/null
+++ b/JPratt/src/main/java/bjc/pratt/tokens/TokenStream.java
@@ -0,0 +1,104 @@
+package bjc.pratt.tokens;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Set;
+
+import bjc.utils.funcutils.StringUtils;
+import bjc.utils.parserutils.ParserException;
+
+/**
+ * A stream of tokens.
+ *
+ * @author EVE
+ *
+ * @param <K>
+ *                The key type of the token.
+ *
+ * @param <V>
+ *                The value type of the token.
+ */
+public abstract class TokenStream<K, V> implements Iterator<Token<K, V>> {
+	/**
+	 * The exception thrown when an expectation fails.
+	 *
+	 * @author EVE
+	 *
+	 */
+	public static class ExpectationException extends ParserException {
+		private static final long serialVersionUID = 4299299480127680805L;
+
+		/**
+		 * Create a new exception with the specified message.
+		 *
+		 * @param msg
+		 *                The message of the exception.
+		 */
+		public ExpectationException(final String msg) {
+			super(msg);
+		}
+	}
+
+	/**
+	 * Get the current token.
+	 *
+	 * @return The current token.
+	 */
+	public abstract Token<K, V> current();
+
+	@Override
+	public abstract Token<K, V> next();
+
+	@Override
+	public abstract boolean hasNext();
+
+	/**
+	 * Utility method for checking that the next token is one of a specific
+	 * set of types, and then consuming it.
+	 *
+	 * @param expectedKeys
+	 *                The expected values
+	 *
+	 * @throws ExpectationException
+	 *                 If the token is not one of the expected types.
+	 */
+	public void expect(final Set<K> expectedKeys) throws ExpectationException {
+		final K curKey = current().getKey();
+
+		if (!expectedKeys.contains(curKey)) {
+			final String expectedList = StringUtils.toEnglishList(expectedKeys.toArray(), false);
+
+			throw new ExpectationException("One of '" + expectedList + "' was expected, not " + curKey);
+		}
+
+		next();
+	}
+
+	/**
+	 * Utility method for checking that the next token is one of a specific
+	 * set of types, and then consuming it.
+	 *
+	 * @param expectedKeys
+	 *                The expected values
+	 *
+	 * @throws ExpectationException
+	 *                 If the token is not one of the expected types.
+	 */
+	@SafeVarargs
+	public final void expect(final K... expectedKeys) throws ExpectationException {
+		expect(new HashSet<>(Arrays.asList(expectedKeys)));
+	}
+
+	/**
+	 * Check whether the head token is a certain type.
+	 *
+	 * @param val
+	 *                The type to check for.
+	 *
+	 * @return Whether or not the head token is of that type.
+	 */
+	public boolean headIs(final K val) {
+		return current().getKey().equals(val);
+	}
+}