diff --git a/input/src/input_dsl.rs b/input/src/input_dsl.rs
index 1e67b37..3a79fd4 100644
--- a/input/src/input_dsl.rs
+++ b/input/src/input_dsl.rs
@@ -1,4 +1,5 @@
 use crate::*;
+use std::marker::PhantomData;
 
 /// A [Command] that can be constructed from a [Token].
 pub trait DslCommand<'a, C>: TryFromDsl<'a, C> + Command<C> {}
@@ -71,59 +72,84 @@ impl<'a, S, C: DslCommand<'a, S>, I: DslInput> KeyMap<'a, S, C, I> for TokenIter
 
 /// A collection of pre-configured mappings of input events to commands,
 /// which may be made available subject to given conditions.
-pub struct InputMap<'a, S, C: DslCommand<'a, S>, I: DslInput> {
+pub struct InputMap<'a, S, C: DslCommand<'a, S>, I: DslInput, M: KeyMap<'a, S, C, I> + Send + Sync> {
+    __: &'a PhantomData<(S, C, I)>,
     layers: Vec<(
-        Box<dyn Fn(&S)->bool + Send + Sync + 'a>,
-        Box<dyn KeyMap<'a, S, C, I> + Send + Sync + 'a>
+        fn(&S)->bool,
+        M
     )>,
 }
 
-impl<'a, S, C: DslCommand<'a, S>, I: DslInput> Default for InputMap<'a, S, C, I> {
+impl<'a, S, C, I, M> Default for InputMap<'a, S, C, I, M>
+where
+    C: DslCommand<'a, S>,
+    I: DslInput,
+    M: KeyMap<'a, S, C, I> + Send + Sync
+{
     fn default () -> Self {
         Self {
+            __: &PhantomData,
             layers: vec![]
         }
     }
 }
 
-impl<'a, S, C: DslCommand<'a, S>, I: DslInput> InputMap<'a, S, C, I> {
-    pub fn new (keymap: impl KeyMap<'a, S, C, I> + Send + Sync + 'a) -> Self {
+impl<'a, S, C, I, M> InputMap<'a, S, C, I, M>
+where
+    C: DslCommand<'a, S>,
+    I: DslInput,
+    M: KeyMap<'a, S, C, I> + Send + Sync
+{
+    pub fn new (keymap: M) -> Self {
         Self::default().layer(keymap)
     }
-    pub fn layer (
-        mut self, keymap: impl KeyMap<'a, S, C, I> + Send + Sync + 'a
-    ) -> Self {
+    pub fn layer (mut self, keymap: M) -> Self {
         self.add_layer(keymap);
         self
     }
-    pub fn add_layer (
-        &mut self, keymap: impl KeyMap<'a, S, C, I> + Send + Sync + 'a
-    ) -> &mut Self {
+    pub fn add_layer (&mut self, keymap: M) -> &mut Self {
         self.add_layer_if(|_|true, keymap);
         self
     }
-    pub fn layer_if (
-        mut self,
-        condition: impl Fn(&S)->bool + Send + Sync + 'a,
-        keymap:    impl KeyMap<'a, S, C, I> + Send + Sync + 'a
-    ) -> Self {
+    pub fn layer_if (mut self, condition: fn(&S)->bool, keymap: M) -> Self {
         self.add_layer_if(condition, keymap);
         self
     }
-    pub fn add_layer_if (
-        &mut self,
-        condition: impl Fn(&S)->bool + Send + Sync + 'a,
-        keymap:    impl KeyMap<'a, S, C, I> + Send + Sync + 'a
-    ) -> &mut Self {
-        self.layers.push((Box::new(condition), Box::new(keymap)));
+    pub fn add_layer_if (&mut self, condition: fn(&S)->bool, keymap: M) -> &mut Self {
+        self.layers.push((condition, keymap));
         self
     }
 }
 
+impl<'a, S, C, I, M> std::fmt::Debug for InputMap<'a, S, C, I, M>
+where
+    C: DslCommand<'a, S>,
+    I: DslInput,
+    M: KeyMap<'a, S, C, I> + Send + Sync
+{
+    fn fmt (&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+        write!(f, "[InputMap: {} layer(s)]", self.layers.len());
+        Ok(())
+    }
+}
+
 /// An [InputMap] can be a [KeyMap].
-impl<'a, S, C: DslCommand<'a, S>, I: DslInput> KeyMap<'a, S, C, I> for InputMap<'a, S, C, I> {
+impl<'a, S, C, I, M> KeyMap<'a, S, C, I> for InputMap<'a, S, C, I, M>
+where
+    C: DslCommand<'a, S>,
+    I: DslInput,
+    M: KeyMap<'a, S, C, I> + Send + Sync
+{
     fn command (&'a self, state: &'a S, input: &'a I) -> Option<C> {
-        todo!()
+        for (condition, keymap) in self.layers.iter() {
+            if !condition(state) {
+                continue
+            }
+            if let Some(command) = keymap.command(state, input) {
+                return Some(command)
+            }
+        }
+        None
     }
 }