Added a //deform command, which deforms a region given an expression that operates on the x/y/z variables.

src/main/java/com/sk89q/worldedit/EditSession.java

@@ -2642,4 +2642,33 @@ public class EditSession {
 
         return shape.generate(this, pattern, hollow);
     }
+
+    public int deformRegion(final Region region, final Vector zero, final Vector unit, final String expressionString) throws ExpressionException, MaxChangedBlocksException {
+        final Expression expression = Expression.compile(expressionString, "x", "y", "z");
+        expression.optimize();
+
+        final RValue x = expression.getVariable("x");
+        final RValue y = expression.getVariable("y");
+        final RValue z = expression.getVariable("z");
+
+        int affected = 0;
+
+        for (BlockVector position : region) {
+            final Vector scaled = position.subtract(zero).divide(unit);
+
+            expression.evaluate(scaled.getX(), scaled.getY(), scaled.getZ());
+
+            final Vector sourceScaled = new Vector(x.getValue(), y.getValue(), z.getValue());
+
+            final BlockVector sourcePosition = sourceScaled.multiply(unit).add(zero).toBlockPoint();
+
+            BaseBlock material = new BaseBlock(world.getBlockType(sourcePosition), world.getBlockData(sourcePosition));
+
+            if (setBlock(position, material)) {
+                ++affected;
+            }
+        }
+
+        return affected;
+    }
 }

src/main/java/com/sk89q/worldedit/commands/RegionCommands.java

@@ -29,6 +29,7 @@ import static com.sk89q.minecraft.util.commands.Logging.LogMode.*;
 import com.sk89q.worldedit.*;
 import com.sk89q.worldedit.blocks.BaseBlock;
 import com.sk89q.worldedit.blocks.BlockID;
+import com.sk89q.worldedit.expression.ExpressionException;
 import com.sk89q.worldedit.filtering.GaussianKernel;
 import com.sk89q.worldedit.filtering.HeightMapFilter;
 import com.sk89q.worldedit.masks.Mask;
@@ -325,4 +326,48 @@ public class RegionCommands {
         session.setMask(mask);
         player.print("Region regenerated.");
     }
+
+    @Command(
+            aliases = { "/deform" },
+            usage = "<expression>",
+            desc = "Deforms a selected region with an expression",
+            flags = "ro",
+            min = 1,
+            max = -1
+    )
+    @CommandPermissions("worldedit.region.deform")
+    @Logging(ALL)
+    public static void deform(CommandContext args, WorldEdit we,
+            LocalSession session, LocalPlayer player, EditSession editSession)
+            throws WorldEditException {
+
+        final Region region = session.getSelection(player.getWorld());
+
+        final String expression = args.getJoinedStrings(0);
+
+        final Vector zero;
+        final Vector unit;
+
+        if (args.hasFlag('r')) {
+            zero = new Vector(0,0,0);
+            unit = new Vector(1,1,1);
+        } else if (args.hasFlag('o')) {
+            zero = session.getPlacementPosition(player);
+            unit = new Vector(1,1,1);
+        } else {
+            final Vector min = region.getMinimumPoint();
+            final Vector max = region.getMaximumPoint();
+
+            zero = max.add(min).multiply(0.5);
+            unit = max.subtract(zero);
+        }
+
+        try {
+            final int affected = editSession.deformRegion(region, zero, unit, expression);
+            player.findFreePosition();
+            player.print(affected + " block(s) have been deformed.");
+        } catch (ExpressionException e) {
+            player.printError(e.getMessage());
+        }
+    }
 }