# HG changeset patch
# User Zachary Kanfer <zkanfer@gmail.com>
# Date 1673840611 18000
#      Sun Jan 15 22:43:31 2023 -0500
# Node ID 2fa2da5461494a26f90ac1a5d82225c00485cac6
# Parent  a4de88b45d865218bb0fd024cd4e8385a9fe032f
add boulders

diff --git a/sand.el b/sand.el
--- a/sand.el
+++ b/sand.el
@@ -45,6 +45,7 @@
 (defvar sand//representations
   (ht ('sand "o")
       ('rock "@")
+      ('boulder "V")
       ('glass "a")
       ('ledge "_")
       ('angle-left "/")
@@ -92,7 +93,7 @@
         (remove item sand//spawnable-items)))
 
 (defvar sand//blowupable-items
-  (list 'sand 'rock 'glass 'antimatter 'balloon))
+  (list 'sand 'rock 'boulder 'glass 'antimatter 'balloon))
 
 (defun sand//blowupable (item)
   "Return whether ITEM can be blown up."
@@ -329,6 +330,7 @@
       (sand//insert-toggleable-item-description 'sand "falls down")
       (sand//insert-toggleable-item-description 'rock "falls through sand")
       (sand//insert-toggleable-item-description 'glass "crushed by rock")
+      (sand//insert-toggleable-item-description 'boulder "like rock, but falls twice as fast")
       (sand//insert-toggleable-item-description 'antimatter "annihilates what it touches")
       (sand//insert-toggleable-item-description 'balloon "floats up")
       (sand//insert-toggleable-item-description 'bomb "explodes when it stops moving")
@@ -428,7 +430,7 @@
          t))
    ((seq-contains-p sand//consuming-items to-thing) t)
    ((seq-contains-p sand//consuming-items from-thing) t)
-   ((eq from-thing 'rock)
+   ((seq-contains-p '(rock boulder) from-thing)
     (seq-contains-p '(sand glass) to-thing))))
 
 (defun sand//direction-to-drop (row column)
@@ -604,7 +606,16 @@
                   (delta-column (elt step 1))
                   (to-row (+ row delta-row))
                   (to-column (+ column delta-column)))
-             (sand//move-sand row column to-row to-column)))))))
+             (sand//move-sand row column to-row to-column)
+
+             (when (equal this-cell 'boulder)
+               ;;just do it again!
+               (let* ((step (sand//direction-to-drop to-row to-column))
+                      (delta-row (elt step 0))
+                      (delta-column (elt step 1))
+                      (second-to-row (+ to-row delta-row))
+                      (second-to-column (+ to-column delta-column)))
+                 (sand//move-sand to-row to-column second-to-row second-to-column)))))))))
 
 (defun sand/blank-board ()
   "Make the entire board blank."
diff --git a/sand.tests.el b/sand.tests.el
--- a/sand.tests.el
+++ b/sand.tests.el
@@ -39,6 +39,11 @@
   (should (sand//can-drop-to 'antimatter 'smoke))
   (should (sand//can-drop-to 'antimatter 'smoke1)))
 
+(ert-deftest can-drop-to/boulder ()
+  (should (sand//can-drop-to 'boulder nil))
+  (should-not (sand//can-drop-to 'boulder 'ledge))
+  (should (sand//can-drop-to 'boulder 'glass)))
+
 (ert-deftest direction-to-drop/balloon ()
   (sand//with-new-board
    (setf (sand//at 0 3) 'balloon)
@@ -91,6 +96,12 @@
    (should (equal [1 0]
                   (sand//direction-to-drop 2 3)))))
 
+(ert-deftest direction-to-drop/boulder ()
+  (sand//with-new-board
+   (setf (sand//at 4 4) 'boulder)
+   (should (equal [1 0]
+                  (sand//direction-to-drop 4 4)))))
+
 (ert-deftest tick-cell/bare-balloon ()
   (sand//with-new-board
    (setf (sand//at 5 5) 'balloon)
@@ -252,6 +263,15 @@
            (setf non-nil (1+ non-nil)))))
      (should (equal non-nil 3)))))
 
+(ert-deftest tick-cell/boulder ()
+  (sand//with-new-board
+   (setf (sand//at 4 4) 'boulder)
+   (sand//tick-cell 4 4)
+   (should-not (sand//at 4 4))
+   (should-not (sand//at 5 4))
+   (should (equal (sand//at 6 4)
+                  'boulder))))
+
 (ert-deftest move-sand/into-smoke ()
   (sand//with-new-board
    (setf (sand//at 4 5) 'antimatter)
diff --git a/todo.org b/todo.org
--- a/todo.org
+++ b/todo.org
@@ -106,3 +106,6 @@
 CLOSED: [2023-01-09 Mon 23:48]
 * DONE make sand//with-new-board catch errors, reset board
 CLOSED: [2023-01-15 Sun 22:02]
+* DONE heavy thing that moves twice per timestep
+CLOSED: [2023-01-15 Sun 22:42]
+* TODO make boulder/rock have better representations