[reog] rename soul -> world.HEADmain

It makes a bit more sense.

13 files changed, 658 insertions, 503 deletions

diff --git a/ark/CMakeLists.txt b/ark/CMakeLists.txt
index 35e47a9..4e2c259 100644
--- a/ark/CMakeLists.txt
+++ b/ark/CMakeLists.txt
@@ -127,6 +127,7 @@ pkg_check_modules(WLOPT IMPORTED_TARGET
 
 if(WLOPT_FOUND)
   target_link_libraries(ark PRIVATE PkgConfig::WLOPT)
+  target_compile_definitions(ark PRIVATE ARK_HAVE_CAIRO)
 endif()
 
 target_link_directories(ark PUBLIC
diff --git a/ark/README.md b/ark/README.md
index d773e0d..a8be7e1 100644
--- a/ark/README.md
+++ b/ark/README.md
@@ -1,35 +1,35 @@
 Ark (Runtime)
 =============
 
-Ark is a long-running Wayland compositor runtime with a hot-reloadable soul
+Ark is a long-running Wayland compositor runtime with a hot-reloadable world
 interface.
 
 Responsibilities
 ----------------
 
 - Owns the Wayland display lifecycle and wlroots setup.
-- Loads a soul shared object (`.so`) at runtime and routes input/surface events to it.
-- Supports hot-reloading the soul without restarting the compositor.
+- Loads a world shared object (`.so`) at runtime and routes input/surface events to it.
+- Supports hot-reloading the world without restarting the compositor.
 
-Soul interface
+World interface
 --------------
 
-The runtime defines a C ABI that souls must implement (load/start/teardown,
+The runtime defines a C ABI that worlds must implement (load/start/teardown,
 event handlers, and optional state marshal/unmarshal for hot reload). The ABI is
 defined in:
 
-- `ark/include/soul.h`
+- `ark/include/world.h`
 
-Souls should include:
+Worlds should include:
 
-- `ark/include/soul_interface.h`
+- `ark/include/world_interface.h`
 
 Key files
 ---------
 
-- `ark/src/wl.c`: compositor setup + event loop + soul callbacks.
-- `ark/src/soul.c`: dynamic loading, lifecycle, and hot-reload logic.
-- `ark/include/soul.h`: C ABI the soul must implement.
+- `ark/src/wl.c`: compositor setup + event loop + world callbacks.
+- `ark/src/world.c`: dynamic loading, lifecycle, and hot-reload logic.
+- `ark/include/world.h`: C ABI the world must implement.
 
 Building
 --------
@@ -44,7 +44,7 @@ cmake --build ../build --target ark
 Running
 -------
 
-Use the top-level `run` target (builds the bundled soul and launches Ark):
+Use the top-level `run` target (builds the bundled world and launches Ark):
 
 ```sh
 cmake --build ../build --target run
diff --git a/ark/include/soul.h b/ark/include/soul.h
deleted file mode 100644
index fa3415b..0000000
--- a/ark/include/soul.h
+++ /dev/null
@@ -1,111 +0,0 @@
-#ifndef _SOUL_H_
-#define _SOUL_H_
-
-#include <dlfcn.h>
-#include <linux/limits.h>
-#include <pthread.h>
-#include <stdint.h>
-#include <wlr/types/wlr_input_device.h>
-#include <wlr/types/wlr_keyboard.h>
-#include <wlr/types/wlr_pointer.h>
-
-#include "soul_types.h"
-#include "soul_exports.h"
-
-#define MAX_QUEUED_ACTIONS 8
-
-typedef void *dlhandle_t;
-
-/* Opaque state for a soul. Not to be touched by the harness (not that it
- * really can be.) */
-
-struct SOUL;
-/* This structure represents an action requested by the soul for the harness.
- */
-typedef struct {
-  int (*action)(struct SOUL *requester, void *arg);
-  void (*arg_dtor)(void *arg);
-  union {
-    void *ptr_arg;
-    int int_arg;
-    char *str_arg;
-  };
-} requested_action_t;
-
-/*
- * Structure for the soul.
- */
-typedef struct SOUL {
-  /* The argc this soul is loaded with. Typically the argc from main(). */
-  int argc;
-
-  /* The argv this soul is loaded with. Typically the argv from main(). */
-  char **argv;
-
-  /* Filename the soul is loaded from. */
-  char filename[PATH_MAX];
-
-  /* Opaque state of this soul. The state is usually some kind of pointer to
-   * the soul state, but all the harness knows is the opaque state is a
-   * pointer-sized piece of data.
-   *
-   * This opaque state is used in a linear pattern where the handlers take the
-   * opaque state, maybe operate on it, and return a new opaque state, which is
-   * then passed to the next handler, etc. It is on the soul to properly
-   * manager the memory for this state and to destroy it upon teardown.
-   *
-   * It's guaranteed that this state is used linearly, meaning the harness gives
-   * up all ownership to it once passed into a handler. */
-  opqst_t state;
-
-  /* This soul's lock. This avoids potential issues with multiple threads
-   * trying to change the opaque state at once which can lead to undesireable
-   * outcomes. */
-  pthread_mutex_t lock;
-
-  /** Set to not-zero if this soul is initialized, otherwise set to zero. */
-  int initialized;
-
-  /* The handle to the shared library. */
-  dlhandle_t library_handle;
-
-  /* Pointer to the soul name. This is in the shared library and a
-   * null-terminated string. If the library does not have a soul name, this
-   * will be NULL. */
-  const char *soul_name;
-
-  /* Soul function table populated by the runtime loader. */
-#define SOUL_FN_PTR(ret, name, args) ret (*name) args;
-  ARKSOUL_EXPORTS(SOUL_FN_PTR)
-#undef SOUL_FN_PTR
-
-  /* List of requested actions by the soul. Right now there is a maximum of 8
-   * allowed at one time. That should be plenty. The actions should be flushed
-   * after each call to a handler anyway. */
-  size_t n_requested_actions;
-  requested_action_t requested_actions[MAX_QUEUED_ACTIONS];
-} soul_t;
-
-/* Reloads the soul. This tears down the existing soul, marshals the state
- * for it and reloads it.
- *
- * This function will call dlclose on the soul's library handle.
- */
-int soul_hot_reload(int argc, char **argv, const char *filepath, soul_t *soul);
-
-/*
- * Like hot-reload, but uses the same parameters the soul was originally
- * loaded with.
- */
-int soul_hot_reload_same_state(soul_t *soul);
-
-/* Starts a soul in a cold state. Called after load_soul_from_file. */
-void soul_cold_start(soul_t *soul);
-
-/* Reads a soul from a filename. */
-int load_soul_from_file(int argc, char **argv, const char *filename,
-                        soul_t *soul);
-
-void soul_run_requested_actions(soul_t *soul);
-
-#endif /* _SOUL_H_ */
diff --git a/ark/include/soul_interface.h b/ark/include/soul_interface.h
deleted file mode 100644
index 6e45573..0000000
--- a/ark/include/soul_interface.h
+++ /dev/null
@@ -1,23 +0,0 @@
-#ifndef _SOUL_INTF
-#define _SOUL_INTF
-
-#include <stdint.h>
-
-#include "soul_types.h"
-#include "soul_exports.h"
-
-#include <wlr/types/wlr_input_device.h>
-#include <wlr/types/wlr_keyboard.h>
-#include <wlr/types/wlr_pointer.h>
-
-/*
- * Soul ABI: souls must export these symbols.
- *
- * This header is intended to be included by soul implementations.
- */
-
-#define DECLARE_SOUL_EXPORT(ret, name, args) ret name args;
-ARKSOUL_EXPORTS(DECLARE_SOUL_EXPORT)
-#undef DECLARE_SOUL_EXPORT
-
-#endif /* _SOUL_INTF */
diff --git a/ark/include/wl.h b/ark/include/wl.h
index e5cf4f3..725025c 100644
--- a/ark/include/wl.h
+++ b/ark/include/wl.h
@@ -21,105 +21,109 @@
 #include <wlr/types/wlr_seat.h>
 #include <wlr/types/wlr_subcompositor.h>
 #include <wlr/types/wlr_xcursor_manager.h>
-#include <wlr/types/wlr_xdg_shell.h>
 #include <wlr/types/wlr_xdg_decoration_v1.h>
+#include <wlr/types/wlr_xdg_shell.h>
 #include <wlr/util/log.h>
 #include <xkbcommon/xkbcommon.h>
 
-#include <soul.h>
+#include <world.h>
 
 /* For brevity's sake, struct members are annotated where they are used. */
 enum montis_cursor_mode {
-	TINYWL_CURSOR_PASSTHROUGH,
-	TINYWL_CURSOR_MOVE,
-	TINYWL_CURSOR_RESIZE,
+  TINYWL_CURSOR_PASSTHROUGH,
+  TINYWL_CURSOR_MOVE,
+  TINYWL_CURSOR_RESIZE,
 };
 
 struct montis_server {
-	struct wl_display *wl_display;
-	struct wlr_backend *backend;
-	struct wlr_renderer *renderer;
-	struct wlr_allocator *allocator;
-	struct wlr_scene *scene;
-	struct wlr_scene_output_layout *scene_layout;
-
-	struct wlr_xdg_shell *xdg_shell;
-	struct wl_listener new_xdg_toplevel;
-	struct wl_listener new_xdg_popup;
-	struct wl_list toplevels;
-
-	struct wlr_xdg_decoration_manager_v1 *xdg_decoration_manager;
-	struct wl_listener new_xdg_decoration;
-
-	struct wlr_cursor *cursor;
-	struct wlr_xcursor_manager *cursor_mgr;
-	struct wl_listener cursor_motion;
-	struct wl_listener cursor_motion_absolute;
-	struct wl_listener cursor_button;
-	struct wl_listener cursor_axis;
-	struct wl_listener cursor_frame;
-
-	struct wlr_seat *seat;
-	struct wl_listener new_input;
-	struct wl_listener request_cursor;
-	struct wl_listener request_set_selection;
-	struct wl_list keyboards;
-	enum montis_cursor_mode cursor_mode;
-	struct montis_toplevel *grabbed_toplevel;
-	double grab_x, grab_y;
-	struct wlr_box grab_geobox;
-	uint32_t resize_edges;
-
-	struct wlr_output_layout *output_layout;
-	struct wl_list outputs;
-	struct wl_listener new_output;
+  struct wl_display *wl_display;
+  struct wlr_backend *backend;
+  struct wlr_renderer *renderer;
+  struct wlr_allocator *allocator;
+  struct wlr_scene *scene;
+  struct wlr_scene_output_layout *scene_layout;
+
+  struct wlr_xdg_shell *xdg_shell;
+  struct wl_listener new_xdg_toplevel;
+  struct wl_listener new_xdg_popup;
+  struct wl_list toplevels;
+
+  struct wlr_xdg_decoration_manager_v1 *xdg_decoration_manager;
+  struct wl_listener new_xdg_decoration;
+
+  struct wlr_cursor *cursor;
+  struct wlr_xcursor_manager *cursor_mgr;
+  struct wl_listener cursor_motion;
+  struct wl_listener cursor_motion_absolute;
+  struct wl_listener cursor_button;
+  struct wl_listener cursor_axis;
+  struct wl_listener cursor_frame;
+
+  struct wlr_seat *seat;
+  struct wl_listener new_input;
+  struct wl_listener request_cursor;
+  struct wl_listener request_set_selection;
+  struct wl_list keyboards;
+  enum montis_cursor_mode cursor_mode;
+  struct montis_toplevel *grabbed_toplevel;
+  double grab_x, grab_y;
+  struct wlr_box grab_geobox;
+  uint32_t resize_edges;
+
+  struct wlr_output_layout *output_layout;
+  struct wl_list outputs;
+  struct wl_listener new_output;
+
+  struct wlr_buffer *background_buffer;
+  char *background_path;
 
   struct wlr_session *session;
-  soul_t soul;
+  world_t world;
 };
 
 struct montis_output {
-	struct wl_list link;
-	struct montis_server *server;
-	struct wlr_output *wlr_output;
-	struct wl_listener frame;
-	struct wl_listener request_state;
-	struct wl_listener destroy;
+  struct wl_list link;
+  struct montis_server *server;
+  struct wlr_output *wlr_output;
+  struct wl_listener frame;
+  struct wl_listener request_state;
+  struct wl_listener destroy;
+  struct wlr_scene_buffer *background;
 };
 
 struct montis_toplevel {
-	struct wl_list link;
-	struct montis_server *server;
-	struct wlr_xdg_toplevel *xdg_toplevel;
-	struct wlr_scene_tree *scene_tree;
-	struct wl_listener map;
-	struct wl_listener unmap;
-	struct wl_listener destroy;
-	struct wl_listener commit;
-	struct wl_listener request_move;
-	struct wl_listener request_resize;
-	struct wl_listener request_maximize;
-	struct wl_listener request_fullscreen;
+  struct wl_list link;
+  struct montis_server *server;
+  struct wlr_xdg_toplevel *xdg_toplevel;
+  struct wlr_scene_tree *scene_tree;
+  struct wl_listener map;
+  struct wl_listener unmap;
+  struct wl_listener destroy;
+  struct wl_listener commit;
+  struct wl_listener request_move;
+  struct wl_listener request_resize;
+  struct wl_listener request_maximize;
+  struct wl_listener request_fullscreen;
 };
 
 struct montis_keyboard {
-	struct wl_list link;
-	struct montis_server *server;
-	struct wlr_keyboard *wlr_keyboard;
+  struct wl_list link;
+  struct montis_server *server;
+  struct wlr_keyboard *wlr_keyboard;
 
-	struct wl_listener modifiers;
-	struct wl_listener key;
-	struct wl_listener destroy;
+  struct wl_listener modifiers;
+  struct wl_listener key;
+  struct wl_listener destroy;
 };
 
 struct montis_popup {
-	struct wlr_xdg_popup *xdg_popup;
-	struct wl_listener commit;
-	struct wl_listener destroy;
+  struct wlr_xdg_popup *xdg_popup;
+  struct wl_listener commit;
+  struct wl_listener destroy;
 };
 
 struct montis_xdg_decoration {
-	struct wlr_xdg_toplevel_decoration_v1 *decoration;
-	struct wl_listener request_mode;
-	struct wl_listener destroy;
+  struct wlr_xdg_toplevel_decoration_v1 *decoration;
+  struct wl_listener request_mode;
+  struct wl_listener destroy;
 };
diff --git a/ark/include/world.h b/ark/include/world.h
new file mode 100644
index 0000000..307608e
--- /dev/null
+++ b/ark/include/world.h
@@ -0,0 +1,112 @@
+#ifndef _WORLD_H_
+#define _WORLD_H_
+
+#include <dlfcn.h>
+#include <linux/limits.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <wlr/types/wlr_input_device.h>
+#include <wlr/types/wlr_keyboard.h>
+#include <wlr/types/wlr_pointer.h>
+
+#include "world_exports.h"
+#include "world_types.h"
+
+#define MAX_QUEUED_ACTIONS 8
+
+typedef void *dlhandle_t;
+
+/* Opaque state for a world. Not to be touched by the harness (not that it
+ * really can be.) */
+
+struct WORLD;
+/* This structure represents an action requested by the world for the harness.
+ */
+typedef struct {
+  int (*action)(struct WORLD *requester, void *arg);
+  void (*arg_dtor)(void *arg);
+  union {
+    void *ptr_arg;
+    int int_arg;
+    char *str_arg;
+  };
+} requested_action_t;
+
+/*
+ * Structure for the world.
+ */
+typedef struct WORLD {
+  /* The argc this world is loaded with. Typically the argc from main(). */
+  int argc;
+
+  /* The argv this world is loaded with. Typically the argv from main(). */
+  char **argv;
+
+  /* Filename the world is loaded from. */
+  char filename[PATH_MAX];
+
+  /* Opaque state of this world. The state is usually some kind of pointer to
+   * the world state, but all the harness knows is the opaque state is a
+   * pointer-sized piece of data.
+   *
+   * This opaque state is used in a linear pattern where the handlers take the
+   * opaque state, maybe operate on it, and return a new opaque state, which is
+   * then passed to the next handler, etc. It is on the world to properly
+   * manager the memory for this state and to destroy it upon teardown.
+   *
+   * It's guaranteed that this state is used linearly, meaning the harness gives
+   * up all ownership to it once passed into a handler. */
+  opqst_t state;
+
+  /* This world's lock. This avoids potential issues with multiple threads
+   * trying to change the opaque state at once which can lead to undesireable
+   * outcomes. */
+  pthread_mutex_t lock;
+
+  /** Set to not-zero if this world is initialized, otherwise set to zero. */
+  int initialized;
+
+  /* The handle to the shared library. */
+  dlhandle_t library_handle;
+
+  /* Pointer to the world name. This is in the shared library and a
+   * null-terminated string. If the library does not have a world name, this
+   * will be NULL. */
+  const char *world_name;
+
+  /* World function table populated by the runtime loader. */
+#define WORLD_FN_PTR(ret, name, args) ret(*name) args;
+  ARKWORLD_EXPORTS(WORLD_FN_PTR)
+#undef WORLD_FN_PTR
+
+  /* List of requested actions by the world. Right now there is a maximum of 8
+   * allowed at one time. That should be plenty. The actions should be flushed
+   * after each call to a handler anyway. */
+  size_t n_requested_actions;
+  requested_action_t requested_actions[MAX_QUEUED_ACTIONS];
+} world_t;
+
+/* Reloads the world. This tears down the existing world, marshals the state
+ * for it and reloads it.
+ *
+ * This function will call dlclose on the world's library handle.
+ */
+int world_hot_reload(int argc, char **argv, const char *filepath,
+                     world_t *world);
+
+/*
+ * Like hot-reload, but uses the same parameters the world was originally
+ * loaded with.
+ */
+int world_hot_reload_same_state(world_t *world);
+
+/* Starts a world in a cold state. Called after load_world_from_file. */
+void world_cold_start(world_t *world);
+
+/* Reads a world from a filename. */
+int load_world_from_file(int argc, char **argv, const char *filename,
+                         world_t *world);
+
+void world_run_requested_actions(world_t *world);
+
+#endif /* _WORLD_H_ */
diff --git a/ark/include/soul_exports.h b/ark/include/world_exports.h
index 8e22b15..c0ee74e 100644
--- a/ark/include/soul_exports.h
+++ b/ark/include/world_exports.h
@@ -1,42 +1,42 @@
 #pragma once
 
 /*
- * Single source of truth for the soul ABI.
+ * Single source of truth for the world ABI.
  *
  * Consumers must define an X-macro like:
  *   #define X(ret, name, args) ...
  * and then invoke:
- *   ARKSOUL_EXPORTS(X)
+ *   ARKWORLD_EXPORTS(X)
  *
  * Note: this file intentionally does not include headers. Include whatever you
- * need (e.g. <stdint.h>, soul_types.h, wlroots headers) before expanding.
+ * need (e.g. <stdint.h>, world_types.h, wlroots headers) before expanding.
  */
 
-#define ARKSOUL_EXPORTS(X)                                                    \
+#define ARKWORLD_EXPORTS(X)                                                    \
   /*                                                                           \
-   * `arksoul_export_metaload`                                                 \
+   * `arkworld_export_metaload`                                                \
    *                                                                           \
-   * Called at most once per process *per `soul_name`*. This is the place      \
+   * Called at most once per process *per `world_name`*. This is the place     \
    * for truly global initialization that should survive hot reloads (e.g.     \
    * one-time language runtime init, registering global hooks, etc.).          \
    *                                                                           \
    * Notes:                                                                    \
    * - May be a no-op.                                                         \
-   * - Must be safe to call before any other soul entrypoint.                  \
+   * - Must be safe to call before any other world entrypoint.                 \
    */                                                                          \
-  X(void, arksoul_export_metaload, (int argc, char **argv))                    \
+  X(void, arkworld_export_metaload, (int argc, char **argv))                   \
   /*                                                                           \
-   * `arksoul_export_load`                                                     \
+   * `arkworld_export_load`                                                    \
    *                                                                           \
    * Called every time the shared object is loaded (cold start and each hot    \
    * reload). Use this for per-load initialization that must be re-done after  \
    * `dlopen`.                                                                 \
    */                                                                          \
-  X(void, arksoul_export_load, (int argc, char **argv))                        \
+  X(void, arkworld_export_load, (int argc, char **argv))                       \
   /*                                                                           \
-   * `arksoul_export_rebirth`                                                  \
+   * `arkworld_export_rebirth`                                                 \
    *                                                                           \
-   * Called after a hot reload with the previous soul's preserved state.       \
+   * Called after a hot reload with the previous world's preserved state.      \
    * Must return the new live opaque state (`opqst_t`) to be used for future   \
    * handler calls.                                                            \
    *                                                                           \
@@ -45,56 +45,56 @@
    * - `self` is an opaque pointer owned by the runtime; treat it as           \
    * read-only.                                                                \
    */                                                                          \
-  X(opqst_t, arksoul_export_rebirth,                                           \
+  X(opqst_t, arkworld_export_rebirth,                                          \
     (void *self, uint8_t *marshalled_state, uint32_t n))                       \
   /*                                                                           \
-   * `arksoul_export_ensoul`                                                   \
+   * `arkworld_export_enworld`                                                 \
    *                                                                           \
    * Called on first boot when no previous state exists. Must construct and    \
    * return an initial opaque state.                                           \
    */                                                                          \
-  X(opqst_t, arksoul_export_ensoul, (void *self))                              \
+  X(opqst_t, arkworld_export_enworld, (void *self))                            \
   /*                                                                           \
-   * `arksoul_export_preserve`                                                 \
+   * `arkworld_export_preserve`                                                \
    *                                                                           \
-   * Called before unloading the current soul during hot reload. Must          \
+   * Called before unloading the current world during hot reload. Must         \
    * serialize the provided opaque state into a newly allocated byte buffer.   \
    *                                                                           \
    * Ownership:                                                                \
    * - Return a heap-allocated buffer (e.g. `malloc`).                         \
    * - The runtime takes ownership and will `free()` it after                  \
-   * `arksoul_export_rebirth`.                                                 \
+   * `arkworld_export_rebirth`.                                                \
    */                                                                          \
-  X(uint8_t *, arksoul_export_preserve, (opqst_t st, uint32_t *szout))         \
+  X(uint8_t *, arkworld_export_preserve, (opqst_t st, uint32_t * szout))       \
   /*                                                                           \
-   * `arksoul_export_release`                                                  \
+   * `arkworld_export_release`                                                 \
    *                                                                           \
    * Called immediately before the shared object is unloaded. Use this to      \
    * release resources owned by the opaque state (and any per-load resources   \
-   * created in `arksoul_export_load`).                                        \
+   * created in `arkworld_export_load`).                                       \
    */                                                                          \
-  X(void, arksoul_export_release, (opqst_t st))                                \
+  X(void, arkworld_export_release, (opqst_t st))                               \
   /*                                                                           \
-   * `arksoul_export_handle_keybinding`                                        \
+   * `arkworld_export_handle_keybinding`                                       \
    *                                                                           \
    * Called for keyboard events. Returns the updated opaque state. Set         \
    * `*out_handled` to non-zero if the event is consumed.                      \
    */                                                                          \
-  X(opqst_t, arksoul_export_handle_keybinding,                                 \
+  X(opqst_t, arkworld_export_handle_keybinding,                                \
     (struct wlr_keyboard * keyboard, struct wlr_keyboard_key_event * event,    \
      uint32_t modifiers, uint32_t keysym, uint32_t codepoint,                  \
      int *out_handled, opqst_t state))                                         \
   /*                                                                           \
-   * `arksoul_export_handle_button`                                            \
+   * `arkworld_export_handle_button`                                           \
    *                                                                           \
    * Called for pointer button events (mouse/trackpad clicks). Returns the     \
    * updated opaque state.                                                     \
    */                                                                          \
-  X(opqst_t, arksoul_export_handle_button,                                     \
+  X(opqst_t, arkworld_export_handle_button,                                    \
     (struct wlr_pointer_button_event * event, uint32_t modifiers,              \
      opqst_t state))                                                           \
   /*                                                                           \
-   * `arksoul_export_handle_motion`                                            \
+   * `arkworld_export_handle_motion`                                           \
    *                                                                           \
    * Called for pointer motion. Returns the updated opaque state.              \
    *                                                                           \
@@ -103,15 +103,15 @@
    *   (type depends on `is_absolute`).                                        \
    * - `lx`/`ly` are layout coordinates in compositor space.                   \
    */                                                                          \
-  X(opqst_t, arksoul_export_handle_motion,                                     \
+  X(opqst_t, arkworld_export_handle_motion,                                    \
     (void *event, uint32_t modifiers, uint32_t is_absolute, double lx,         \
      double ly, opqst_t state))                                                \
   /*                                                                           \
-   * `arksoul_export_handle_surface`                                           \
+   * `arkworld_export_handle_surface`                                          \
    *                                                                           \
    * Called when a surface is mapped/unmapped/destroyed. `surface` is an       \
    * opaque pointer to the runtime surface representation. Returns the updated \
    * opaque state.                                                             \
    */                                                                          \
-  X(opqst_t, arksoul_export_handle_surface,                                    \
+  X(opqst_t, arkworld_export_handle_surface,                                   \
     (void *surface, surface_event_t event, opqst_t state))
diff --git a/ark/include/world_interface.h b/ark/include/world_interface.h
new file mode 100644
index 0000000..9e703fa
--- /dev/null
+++ b/ark/include/world_interface.h
@@ -0,0 +1,23 @@
+#ifndef _WORLD_INTF
+#define _WORLD_INTF
+
+#include <stdint.h>
+
+#include "world_exports.h"
+#include "world_types.h"
+
+#include <wlr/types/wlr_input_device.h>
+#include <wlr/types/wlr_keyboard.h>
+#include <wlr/types/wlr_pointer.h>
+
+/*
+ * World ABI: worlds must export these symbols.
+ *
+ * This header is intended to be included by world implementations.
+ */
+
+#define DECLARE_WORLD_EXPORT(ret, name, args) ret name args;
+ARKWORLD_EXPORTS(DECLARE_WORLD_EXPORT)
+#undef DECLARE_WORLD_EXPORT
+
+#endif /* _WORLD_INTF */
diff --git a/ark/include/soul_types.h b/ark/include/world_types.h
index df1eab5..df1eab5 100644
--- a/ark/include/soul_types.h
+++ b/ark/include/world_types.h
diff --git a/ark/src/soul.c b/ark/src/soul.c
deleted file mode 100644
index 4268cd5..0000000
--- a/ark/src/soul.c
+++ /dev/null
@@ -1,198 +0,0 @@
-#include "soul.h"
-
-#include <ctype.h>
-#include <dlfcn.h>
-#include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-/* Utility function for showing the marshalled states as hex code */
-static void shx(uint8_t *state, uint32_t sz)
-{
-  uint32_t i = 0;
-  while (i < sz) {
-    for (int j = 0; j < 16; ++j) {
-      if (i < sz) {
-        printf("%02x ", (unsigned int)state[i]);
-      }
-      else {
-        printf("   ");
-      }
-      ++i;
-    }
-
-    i -= 16;
-
-    printf("   ");
-
-    for (int j = 0; j < 16; ++j) {
-      if (i < sz) {
-        if (isprint(state[i]) && !isspace(state[i])) {
-          printf("%c", state[i]);
-        }
-        else {
-          printf(".");
-        }
-      }
-      else {
-        printf(" ");
-      }
-      ++i;
-    }
-    printf("\n");
-  }
-}
-
-int load_soul_from_dl_(dlhandle_t dl, soul_t *soul);
-
-static void lock(soul_t *soul) { pthread_mutex_lock(&soul->lock); };
-
-static void unlock(soul_t *soul) { pthread_mutex_unlock(&soul->lock); };
-
-static int load_soul_from_file_(int argc, char **argv, const char *filename,
-                                soul_t *soul)
-{
-  dlhandle_t lib = dlopen(filename, RTLD_NOW | RTLD_GLOBAL);
-  int ec = 0;
-
-  if (!lib) {
-    fprintf(stderr, "Failed to open library: %s: %s\n", filename, dlerror());
-    ec = 1;
-    goto end;
-  }
-
-  printf("Loading file.\n");
-  ec = load_soul_from_dl_(lib, soul);
-
-  if (ec) {
-    goto end;
-  }
-
-  strncpy(soul->filename, filename, sizeof(soul->filename));
-  soul->argc = argc;
-  soul->argv = argv;
-
-  soul->arksoul_export_load(soul->argc, soul->argv);
-end:
-  return ec;
-}
-
-static void maybe_run_metaload(int argc, char **argv, soul_t *soul)
-{
-  static char *loaded_souls[12];
-  int i;
-  for (i = 0; i < 12 && loaded_souls[i]; ++i) {
-    if (strcmp(loaded_souls[i], soul->soul_name) == 0) {
-      return; // Soul is already loaded
-    }
-  }
-  loaded_souls[i] = strdup(soul->soul_name);
-
-  printf("First time loading %s, running metaload.\n", soul->soul_name);
-  if (soul->arksoul_export_metaload) {
-    soul->arksoul_export_metaload(argc, argv);
-  }
-}
-
-int load_soul_from_file(int argc, char **argv, const char *filename,
-                        soul_t *soul)
-{
-  memset(soul, 0, sizeof(*soul));
-
-  pthread_mutexattr_t attr;
-  if (pthread_mutexattr_init(&attr)) {
-    perror("pthread_mutexattr_init");
-    return 1;
-  }
-
-  if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)) {
-    perror("pthread_mutexattr_settype");
-    return 1;
-  }
-
-  if (pthread_mutex_init(&soul->lock, &attr)) {
-    pthread_mutexattr_destroy(&attr);
-    perror("pthread_mutexattr_init");
-    return 1;
-  }
-  pthread_mutexattr_destroy(&attr);
-  int rc = load_soul_from_file_(argc, argv, filename, soul);
-
-  if (rc == 0) {
-    maybe_run_metaload(argc, argv, soul);
-  }
-
-  return rc;
-}
-
-int soul_hot_reload_same_state(soul_t *soul)
-{
-  char filename_cpy[PATH_MAX];
-  strncpy(filename_cpy, soul->filename, sizeof(filename_cpy));
-  return soul_hot_reload(soul->argc, soul->argv, filename_cpy, soul);
-}
-
-int soul_hot_reload(int argc, char **argv, const char *filepath, soul_t *soul)
-{
-  int ec = 0;
-  uint32_t sz = 0;
-  uint8_t *marshalled_state = NULL;
-
-  printf("Hot Reloading %s\n", soul->soul_name);
-  lock(soul);
-
-  printf("Marshalling state ...\n");
-  marshalled_state = soul->arksoul_export_preserve(soul->state, &sz);
-
-  printf("Calling teardown ...\n");
-  soul->arksoul_export_release(soul->state);
-
-  printf("State Marshalled:\n");
-  shx(marshalled_state, sz);
-
-  printf("Unloading old library handle.\n");
-  if (dlclose(soul->library_handle)) {
-    printf("Could not close library handle: %s\n", dlerror());
-  }
-
-  if ((ec = load_soul_from_file_(argc, argv, filepath, soul))) {
-    goto fail;
-  }
-
-  printf("Hot starting soul ...\n");
-  soul->state = soul->arksoul_export_rebirth(soul, marshalled_state, sz);
-
-fail:
-  free(marshalled_state);
-  unlock(soul);
-  return ec;
-}
-
-void soul_run_requested_actions(soul_t *soul)
-{
-  lock(soul);
-  requested_action_t requested_actions[MAX_QUEUED_ACTIONS];
-  size_t n_requested_actions = soul->n_requested_actions;
-  memcpy(&requested_actions, soul->requested_actions,
-         sizeof(requested_actions));
-  soul->n_requested_actions = 0;
-  unlock(soul);
-
-  size_t i;
-  for (i = 0; i < n_requested_actions; ++i) {
-    requested_actions[i].action(soul, requested_actions[i].str_arg);
-    if (requested_actions[i].arg_dtor) {
-      requested_actions[i].arg_dtor(requested_actions[i].ptr_arg);
-    }
-  }
-}
-
-void soul_cold_