bug with objects moving

kiln-core/src/board.rs

@@ -396,6 +396,33 @@ impl Board {
             .collect()
     }
 
+    /// Tries to walk the object in x,y in the given direction. Pushes the cell in that direction
+    /// first. This won't move anything if:
+    /// - the cell x,y is empty; no-op
+    /// - x,y is out of bounds, no-op
+    /// - the target cell can't be pushed in that direction, either because it's `Block` or
+    ///   something in its chain is
+    pub fn move_object(&mut self, x: usize, y: usize, dir: Direction) {
+        // Is this even a cell?
+        if self.in_bounds((x as i64, y as i64)) {
+            // Is there anything in this cell?
+            if self.get(x, y).is_some() {
+                let (tx, ty) = dir.from_point(x as i64, y as i64);
+                // Is the _target_ in bounds?
+                if self.in_bounds((tx, ty)) {
+                    // Attempt to push the target out of the way
+                    self.push(tx as usize, ty as usize, dir);
+                    // Is the cell now empty?
+                    if self.get(tx as usize, ty as usize).is_none() {
+                        // Then finally, move the thing:
+                        let thing = self.grid[x + y * self.width].take();
+                        self.grid[tx as usize + ty as usize * self.width] = thing;
+                    }
+                }
+            }
+        }
+    }
+
     /// Moves the single solid occupant of `(x, y)` one step by `(dx, dy)`.
     ///
     /// A solid object is relocated; otherwise the solid terrain archetype (a crate)
@@ -636,7 +663,11 @@ pub(crate) mod tests {
     use crate::utils::{Direction, ObjectId};
     use color::Rgba8;
     use std::collections::HashMap;
-    use crate::tile::{DrawLayer, IntoTile, Optics, ScriptAttributes, Sensor, SensorSpec, Tile, TileSpec};
+    use crate::object_def::ObjectDef;
+    use crate::tile::{
+        DrawLayer, EnterResponse, IntoTile, Optics, ScriptAttributes, Sensor, SensorSpec, Tile,
+        TileSpec,
+    };
 
     /// Builds an all-empty `w×h` board.
     ///
@@ -704,6 +735,60 @@ pub(crate) mod tests {
         id
     }
 
+    /// Stamps a scripted object at `(x, y)` running the world script named `script`,
+    /// answering entry attempts with `enter`, and returns its id.
+    ///
+    /// The on-grid counterpart to [`sensor_at`]: this object occupies its cell and
+    /// takes part in collision, so `enter` decides how it responds to something
+    /// moving into it (`Block` for an ordinary solid, `Push(..)` for a shovable one).
+    pub(crate) fn object_at(
+        board: &mut Board,
+        x: usize,
+        y: usize,
+        script: &str,
+        enter: EnterResponse,
+    ) -> ObjectId {
+        let tile = TileSpec::Object {
+            script: Some(script.to_string()),
+            enter,
+            glyph: ObjectDef::default_glyph(),
+            optics: Optics { opaque: true, glow: 0 },
+            name: None,
+            tags: Vec::new(),
+        }
+        .into_tile(&mut board.next_object_id)
+        .expect("an object spec always resolves");
+        let id = match &tile {
+            Tile::Object(obj) => obj.scripting.id,
+            Tile::Player => unreachable!("an object spec never resolves to the player"),
+        };
+        *board.get_mut(x, y) = Some(tile);
+        id
+    }
+
+    /// Stamps a solid object at `(x, y)` with **no script attached**, returning its id.
+    ///
+    /// For exercising the "an object without a script is inert" path; everything
+    /// else should use [`object_at`].
+    pub(crate) fn plain_object_at(board: &mut Board, x: usize, y: usize) -> ObjectId {
+        let tile = TileSpec::Object {
+            script: None,
+            enter: EnterResponse::Block,
+            glyph: ObjectDef::default_glyph(),
+            optics: Optics { opaque: true, glow: 0 },
+            name: None,
+            tags: Vec::new(),
+        }
+        .into_tile(&mut board.next_object_id)
+        .expect("an object spec always resolves");
+        let id = match &tile {
+            Tile::Object(obj) => obj.scripting.id,
+            Tile::Player => unreachable!("an object spec never resolves to the player"),
+        };
+        *board.get_mut(x, y) = Some(tile);
+        id
+    }
+
     /// Adds an invisible, script-only [`Sensor`] at `(x, y)` running the world script
     /// named `script`, returning its id.
     ///