what is up with those tests!

input/src/event_map.rs

@@ -1,3 +1,5 @@
+use crate::*;
+
 pub struct EventMap<'a, S, I: PartialEq, C> {
     pub bindings: &'a [(I, &'a dyn Fn(&S) -> Option<C>)],
     pub fallback: Option<&'a dyn Fn(&S, &I) -> Option<C>>
@@ -40,3 +42,32 @@ impl<'a, S, I: PartialEq, C> EventMap<'a, S, I, C> {
         input_to_command!($(<$lt>)? $Command: |$state: $State, input: $Input|$KEYS.handle($state, input)?);
     };
 }
+#[macro_export] macro_rules! input_to_command {
+    (<$($l:lifetime),+> $Command:ty: |$state:ident:$State:ty, $input:ident:$Input:ty| $handler:expr) => {
+        impl<$($l),+> InputToCommand<$Input, $State> for $Command {
+            fn input_to_command ($state: &$State, $input: &$Input) -> Option<Self> {
+                Some($handler)
+            }
+        }
+    };
+    ($Command:ty: |$state:ident:$State:ty, $input:ident:$Input:ty| $handler:expr) => {
+        impl InputToCommand<$Input, $State> for $Command {
+            fn input_to_command ($state: &$State, $input: &$Input) -> Option<Self> {
+                Some($handler)
+            }
+        }
+    }
+}
+
+pub trait InputToCommand<I, S>: Command<S> + Sized {
+    fn input_to_command (state: &S, input: &I) -> Option<Self>;
+    fn execute_with_state (state: &mut S, input: &I) -> Perhaps<bool> {
+        Ok(if let Some(command) = Self::input_to_command(state, input) {
+            let _undo = command.execute(state)?;
+            Some(true)
+        } else {
+            None
+        })
+    }
+}
+