Split state handing into multiple modules.

Author: HexDecimal

g.py

@@ -0,0 +1,16 @@
+"""This module stores globally mutable variables used by this program."""
+from __future__ import annotations
+
+import tcod.console
+import tcod.context
+
+import game.state
+
+console: tcod.console.Console
+"""The main console."""
+
+context: tcod.context.Context
+"""The window managed by tcod."""
+
+states: list[game.state.State] = []
+"""A stack of states with the last item being the active state."""

game/state.py

@@ -0,0 +1,17 @@
+"""Base classes for states."""
+from __future__ import annotations
+
+from typing import Protocol
+
+import tcod.console
+import tcod.event
+
+
+class State(Protocol):
+    """An abstract game state."""
+
+    def on_event(self, event: tcod.event.Event) -> None:
+        """Called on events."""
+
+    def on_draw(self, console: tcod.console.Console) -> None:
+        """Called when the state is being drawn."""

game/state_tools.py

@@ -0,0 +1,23 @@
+"""State handling functions."""
+import tcod.console
+
+import g
+
+
+def main_draw() -> None:
+    """Render and present the active state."""
+    if not g.states:
+        return
+    g.console.clear()
+    g.states[-1].on_draw(g.console)
+    g.context.present(g.console)
+
+
+def main_loop() -> None:
+    """Run the active state forever."""
+    while g.states:
+        main_draw()
+        for event in tcod.event.wait():
+            print(event)
+            if g.states:
+                g.states[-1].on_event(event)

game/states.py

@@ -0,0 +1,35 @@
+"""A collection of game states."""
+from __future__ import annotations
+
+import attrs
+import tcod.console
+import tcod.event
+from tcod.event import KeySym
+
+
+@attrs.define(eq=False)
+class ExampleState:
+    """Example state with a hard-coded player position."""
+
+    player_x: int
+    """Player X position, left-most position is zero."""
+    player_y: int
+    """Player Y position, top-most position is zero."""
+
+    def on_event(self, event: tcod.event.Event) -> None:
+        """Move the player on events and handle exiting. Movement is hard-coded."""
+        match event:
+            case tcod.event.Quit():
+                raise SystemExit()
+            case tcod.event.KeyDown(sym=KeySym.LEFT):
+                self.player_x -= 1
+            case tcod.event.KeyDown(sym=KeySym.RIGHT):
+                self.player_x += 1
+            case tcod.event.KeyDown(sym=KeySym.UP):
+                self.player_y -= 1
+            case tcod.event.KeyDown(sym=KeySym.DOWN):
+                self.player_y += 1
+
+    def on_draw(self, console: tcod.console.Console) -> None:
+        """Draw the player with print. Bounds do not need to be checked with this function."""
+        console.print(self.player_x, self.player_y, "@")

main.py

@@ -2,39 +2,14 @@
 """Main entry-point module. This script is used to start the program."""
 from __future__ import annotations
 
-import attrs
 import tcod.console
 import tcod.context
 import tcod.event
 import tcod.tileset
 
-
-@attrs.define(eq=False)
-class ExampleState:
-    """Example state with a hard-coded player position."""
-
-    player_x: int
-    """Player X position, left-most position is zero."""
-    player_y: int
-    """Player Y position, top-most position is zero."""
-
-    def on_event(self, event: tcod.event.Event) -> None:
-        """Move the player on events and handle exiting. Movement is hard-coded."""
-        match event:
-            case tcod.event.Quit():
-                raise SystemExit()
-            case tcod.event.KeyDown(sym=tcod.event.KeySym.LEFT):
-                self.player_x -= 1
-            case tcod.event.KeyDown(sym=tcod.event.KeySym.RIGHT):
-                self.player_x += 1
-            case tcod.event.KeyDown(sym=tcod.event.KeySym.UP):
-                self.player_y -= 1
-            case tcod.event.KeyDown(sym=tcod.event.KeySym.DOWN):
-                self.player_y += 1
-
-    def on_draw(self, console: tcod.console.Console) -> None:
-        """Draw the player with print. Bounds do not need to be checked with this function."""
-        console.print(self.player_x, self.player_y, "@")
+import g
+import game.state_tools
+import game.states
 
 
 def main() -> None:
@@ -43,15 +18,10 @@ def main() -> None:
         "data/Alloy_curses_12x12.png", columns=16, rows=16, charmap=tcod.tileset.CHARMAP_CP437
     )
     tcod.tileset.procedural_block_elements(tileset=tileset)
-    console = tcod.console.Console(80, 50)
-    state = ExampleState(player_x=console.width // 2, player_y=console.height // 2)
-    with tcod.context.new(console=console, tileset=tileset) as context:
-        while True:  # Main loop
-            console.clear()  # Clear the console before any drawing
-            state.on_draw(console)  # Draw the current state
-            context.present(console)  # Render the console to the window and show it
-            for event in tcod.event.wait():  # Event loop, blocks until pending events exist
-                state.on_event(event)  # Dispatch events to the state
+    g.console = tcod.console.Console(80, 50)
+    g.states = [game.states.ExampleState(player_x=g.console.width // 2, player_y=g.console.height // 2)]
+    with tcod.context.new(console=g.console, tileset=tileset) as g.context:
+        game.state_tools.main_loop()
 
 
 if __name__ == "__main__":