Added an expression parser.

src/main/java/com/sk89q/worldedit/expression/Identifiable.java

@@ -0,0 +1,46 @@
+// $Id$
+/*
+ * WorldEdit
+ * Copyright (C) 2010, 2011 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package com.sk89q.worldedit.expression;
+
+public interface Identifiable {
+    /**
+     * Returns a character that helps identify the token, pseudo-token or invokable in question.
+     *
+     * <pre>
+     * Tokens:
+     * i - IdentifierToken
+     * 0 - NumberToken
+     * o - OperatorToken
+     * \0 - NullToken
+     * CharacterTokens are returned literally
+     *
+     * PseudoTokens:
+     * p - PrefixOperator
+     *
+     * Invokables:
+     * c - Constant
+     * f - Function
+     * v - Variable
+     * </pre>
+     */
+    public abstract char id();
+
+    public int getPosition();
+}