Better response + argument len managed at lib level

src/events.rs

@@ -132,12 +132,14 @@ impl Irc {
             .run_system(prefix, elements.collect(), &sys_name)
             .await;
 
-        if response.0.is_none() {
-            return;
-        }
-
-        for line in response.0.unwrap() {
-            context.privmsg(channel, &line)
+        match response {
+            crate::system::Response::Lines(lines) => {
+                for line in lines {
+                    context.privmsg(channel, &line)
+                }
+            }
+            crate::system::Response::Empty => return,
+            crate::system::Response::InvalidArgument => return,
         }
     }
 }

src/lib.rs

@@ -321,10 +321,11 @@ impl Context {
                         &[],
                         &mut *fact.write().await,
                     );
-                    if resp.0.is_none() {
-                        continue;
+                    match resp {
+                        Response::Lines(lines) => task_tx.send(lines).await.unwrap(),
+                        Response::Empty => continue,
+                        Response::InvalidArgument => continue,
                     }
-                    task_tx.send(resp.0.unwrap()).await.unwrap()
                 }
             });
         }

src/system.rs

@@ -38,7 +38,12 @@ macro_rules! impl_system {
                 }
 
                 $(
+                    if !$params::valid(prefix, arguments, &factory) {
+                        return Response::InvalidArgument;
+                    }
+
                     let $params = $params::retrieve(prefix, arguments, &factory);
+
                 )*
 
                 call_inner(&mut self.f, $($params),*)
@@ -109,11 +114,22 @@ pub(crate) type StoredSystem = Box<dyn for<'a> System + Send + Sync>;
 
 pub(crate) trait SystemParam {
     type Item<'new>;
-    fn retrieve<'r>(prefix: &'r IrcPrefix, arguments: &'r[&'r str], factory: &'r Factory) -> Self::Item<'r>;
+    fn retrieve<'r>(
+        prefix: &'r IrcPrefix,
+        arguments: &'r [&'r str],
+        factory: &'r Factory,
+    ) -> Self::Item<'r>;
+    fn valid(prefix: &IrcPrefix, arguments: &[&str], factory: &Factory) -> bool {
+        true
+    }
 }
 
 #[derive(Clone)]
-pub struct Response(pub Option<Vec<String>>);
+pub enum Response {
+    Lines(Vec<String>),
+    Empty,
+    InvalidArgument,
+}
 
 pub trait IntoResponse {
     fn response(self) -> Response;
@@ -121,25 +137,25 @@ pub trait IntoResponse {
 
 impl IntoResponse for () {
     fn response(self) -> Response {
-        Response(None)
+        Response::Empty
     }
 }
 
 impl IntoResponse for String {
     fn response(self) -> Response {
-        Response(Some(vec![self]))
+        Response::Lines(vec![self])
     }
 }
 
 impl IntoResponse for &str {
     fn response(self) -> Response {
-        Response(Some(vec![self.to_owned()]))
+        Response::Lines(vec![self.to_owned()])
     }
 }
 
 impl IntoResponse for Msg {
     fn response(self) -> Response {
-        Response(Some(vec![self.to_string()]))
+        Response::Lines(vec![self.to_string()])
     }
 }
 
@@ -163,16 +179,14 @@ where
     fn response(self) -> Response {
         match self {
             Some(s) => s.response(),
-            None => Response(None),
+            None => Response::Empty,
         }
     }
 }
 
 impl<T: std::fmt::Display> IntoResponse for Vec<T> {
     fn response(self) -> Response {
-        Response(Some(
-            self.iter().map(|elem| elem.to_string()).collect::<Vec<_>>(),
-        ))
+        Response::Lines(self.iter().map(|elem| elem.to_string()).collect::<Vec<_>>())
     }
 }
 
@@ -180,7 +194,7 @@ macro_rules! impl_into_response_for_primitives {
     ($param:ident) => {
         impl IntoResponse for $param {
             fn response(self) -> Response {
-                Response(Some(vec![self.to_string()]))
+                Response::Lines(vec![self.to_string()])
             }
         }
     };

src/system_params.rs

@@ -108,9 +108,9 @@ impl<'a> SystemParam for IrcPrefix<'a> {
     }
 }
 
-pub struct Arguments<'a>(&'a [&'a str]);
+pub struct Arguments<'a, const N: usize>(&'a [&'a str]);
 
-impl<'a> Deref for Arguments<'a> {
+impl<'a, const N: usize> Deref for Arguments<'a, N> {
     type Target = &'a [&'a str];
 
     fn deref(&self) -> &Self::Target {
@@ -118,14 +118,20 @@ impl<'a> Deref for Arguments<'a> {
     }
 }
 
-impl<'a> SystemParam for Arguments<'a> {
-    type Item<'new> = Arguments<'new>;
+impl<'a, const N: usize> SystemParam for Arguments<'a, N> {
+    type Item<'new> = Arguments<'new, N>;
 
     fn retrieve<'r>(
         _prefix: &'r IrcPrefix,
         arguments: &'r [&'r str],
         _factory: &'r Factory,
     ) -> Self::Item<'r> {
-        Arguments(arguments)
+        Arguments(&arguments[..N])
+    }
+
+    fn valid(_prefix: &IrcPrefix,
+    arguments: &[&str],
+    _factory: &Factory,) -> bool {
+        arguments.len() == N
     }
 }