Add support for anonymous functions in Rust.

src/fn_call.rs

@@ -0,0 +1,47 @@
+//! Helper module which defines `FnArgs` to make function calling easier.
+
+#![allow(non_snake_case)]
+
+use crate::any::{Any, Dynamic};
+
+use crate::stdlib::{string::String, vec, vec::Vec};
+
+/// Trait that represent arguments to a function call.
+/// Any data type that can be converted into a `Vec` of `Dynamic` values can be used
+/// as arguments to a function call.
+pub trait FuncArgs {
+    /// Convert to a `Vec` of `Dynamic` arguments.
+    fn into_vec(self) -> Vec<Dynamic>;
+}
+
+// Macro to implement `FuncArgs` for tuples of standard types (each can be
+/// converted into `Dynamic`).
+macro_rules! impl_args {
+    ($($p:ident),*) => {
+        impl<$($p: Any + Clone),*> FuncArgs for ($($p,)*)
+        {
+            fn into_vec(self) -> Vec<Dynamic> {
+                let ($($p,)*) = self;
+
+                #[allow(unused_variables, unused_mut)]
+                let mut v = Vec::new();
+                $(v.push($p.into_dynamic());)*
+
+                v
+            }
+        }
+
+        impl_args!(@pop $($p),*);
+    };
+    (@pop) => {
+    };
+    (@pop $head:ident) => {
+        impl_args!();
+    };
+    (@pop $head:ident $(, $tail:ident)+) => {
+        impl_args!($($tail),*);
+    };
+}
+
+#[rustfmt::skip]
+impl_args!(A, B, C, D, E, F, G, H, J, K, L, M, N, P, Q, R, S, T, U, V);