Implemented /repl tool that will replace a right clicked block with a block of your choice.

src/com/sk89q/worldedit/WorldEditController.java

@@ -139,6 +139,7 @@ public class WorldEditController {
         commands.put("/none", "Switch to no tool");
         commands.put("/info", "Switch to the info tool");
         commands.put("/tree", "Switch to the tree tool");
+        commands.put("/repl", "[ID] - Switch to the block replacer tool");
         commands.put("//expand", "[Num] <Dir> - Expands the selection");
         commands.put("//contract", "[Num] <Dir> - Contracts the selection");
         commands.put("//shift", "[Num] <Dir> - Shift the selection");
@@ -692,7 +693,15 @@ public class WorldEditController {
             player.print("Info tool equipped. Right click with a pickaxe.");
             return true;
 
-        // Info tool
+        // Replace block tool
+        } else if (split[0].equalsIgnoreCase("/repl")) {
+            checkArgs(split, 1, 1, split[0]);
+            BaseBlock targetBlock = getBlock(player, split[1]);
+            session.setTool(new BlockReplacer(targetBlock));
+            player.print("Block replacer tool equipped. Right click with a pickaxe.");
+            return true;
+
+        // No tool
         } else if (split[0].equalsIgnoreCase("/none")) {
             checkArgs(split, 0, 0, split[0]);
             session.setTool(null);

src/com/sk89q/worldedit/superpickaxe/BlockReplacer.java

@@ -0,0 +1,54 @@
+// $Id$
+/*
+ * WorldEdit
+ * Copyright (C) 2010 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.superpickaxe;
+
+import com.sk89q.worldedit.*;
+import com.sk89q.worldedit.blocks.BaseBlock;
+
+/**
+ * A smode that replaces one block.
+ * 
+ * @author sk89q
+ */
+public class BlockReplacer implements SuperPickaxeMode {
+    private BaseBlock targetBlock;
+    
+    public BlockReplacer(BaseBlock targetBlock) {
+        this.targetBlock = targetBlock;
+    }
+    
+    @Override
+    public boolean act(ServerInterface server, LocalConfiguration config,
+            LocalPlayer player, LocalSession session, LocalWorld world,
+            Vector clicked) {
+        
+        EditSession editSession = new EditSession(server, world, -1);
+        
+        try {
+            editSession.setBlock(clicked, targetBlock);
+        } catch (MaxChangedBlocksException e) {
+        } finally {
+            session.remember(editSession);
+        }
+        
+        return true;
+    }
+
+}