breaking: refactor: cooking

src/play.rs

@@ -0,0 +1,41 @@
+use crate::*;
+
+/// Define an enum containing commands, and implement [Command] trait for over given `State`.
+#[macro_export] macro_rules! def_command (
+    ($Command:ident: |$state:ident: $State:ty| {
+        // FIXME: support attrs (docstrings)
+        $($Variant:ident$({$($arg:ident:$Arg:ty),+ $(,)?})?=>$body:expr),* $(,)?
+    })=>{
+        #[derive(Debug)] pub enum $Command {
+            // FIXME: support attrs (docstrings)
+            $($Variant $({ $($arg: $Arg),* })?),*
+        }
+        impl ::tengri::Command<$State> for $Command {
+            fn execute (&self, $state: &mut $State) -> Perhaps<Self> {
+                match self {
+                    $(Self::$Variant $({ $($arg),* })? => $body,)*
+                    _ => unimplemented!("Command<{}>: {self:?}", stringify!($State)),
+                }
+            }
+        }
+    });
+
+/// Implement [Handle] for given `State` and `handler`.
+#[macro_export] macro_rules! handle {
+    (|$self:ident:$State:ty,$input:ident|$handler:expr) => {
+        impl<E: Engine> ::tengri::Handle<E> for $State {
+            fn handle (&mut $self, $input: &E) -> Perhaps<E::Handled> {
+                $handler
+            }
+        }
+    };
+    ($E:ty: |$self:ident:$State:ty,$input:ident|$handler:expr) => {
+        impl ::tengri::Handle<$E> for $State {
+            fn handle (&mut $self, $input: &$E) ->
+                Perhaps<<$E as ::tengri::Input>::Handled>
+            {
+                $handler
+            }
+        }
+    }
+}