Add better funcion call syntax

src/call.rs

@@ -0,0 +1,36 @@
+//! Helper module which defines `FnArgs`
+//! to make function calling easier.
+
+use any::Any;
+
+pub trait FunArgs<'a> {
+    fn into_vec(self) -> Vec<&'a mut Any>;
+}
+
+macro_rules! impl_args {
+    ($($p:ident),*) => {
+        impl<'a, $($p),*> FunArgs<'a> for ($(&'a mut $p,)*)
+        where
+            $($p: Any + Clone),*
+        {
+            fn into_vec(self) -> Vec<&'a mut Any> {
+                let ($($p,)*) = self;
+
+                let mut v = Vec::new();
+                $(v.push($p as &mut Any);)*
+
+                v
+            }
+        }
+
+        impl_args!(@pop $($p),*);
+    };
+    (@pop) => {
+    };
+    (@pop $head:ident $(, $tail:ident)*) => {
+        impl_args!($($tail),*);
+    };
+}
+
+#[cfg_attr(rustfmt, rustfmt_skip)]
+impl_args!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S);