New Procedural Macros Crate v0.1

src/any.rs

@@ -681,6 +681,13 @@ impl Dynamic {
         }
     }
 
+    /// Copy and return a `Dynamic` if it contains a type that can be trivially copied.
+    /// Returns `None` if the cast fails.
+    #[inline(always)]
+    pub fn downcast_clone<T: Variant + Clone>(&self) -> Option<T> {
+        self.downcast_ref::<T>().map(|t| t.clone())
+    }
+
     /// Cast the `Dynamic` as the system integer type `INT` and return it.
     /// Returns the name of the actual type if the cast fails.
     pub fn as_int(&self) -> Result<INT, &'static str> {

src/fn_register.rs

@@ -43,7 +43,7 @@ pub trait RegisterPlugin<PL: crate::plugin::Plugin> {
     ///     fn is_method_call(&self) -> bool { false }
     ///     fn is_varadic(&self) -> bool { false }
     ///
-    ///     fn call(&self, args: &[&mut Dynamic], pos: Position) -> Result<Dynamic, Box<EvalAltResult>> {
+    ///     fn call(&self, args: &mut[&mut Dynamic], pos: Position) -> Result<Dynamic, Box<EvalAltResult>> {
     ///         let x1: &FLOAT = args[0].downcast_ref::<FLOAT>().unwrap();
     ///         let y1: &FLOAT = args[1].downcast_ref::<FLOAT>().unwrap();
     ///         let x2: &FLOAT = args[2].downcast_ref::<FLOAT>().unwrap();
@@ -55,6 +55,13 @@ pub trait RegisterPlugin<PL: crate::plugin::Plugin> {
     ///     fn clone_boxed(&self) -> Box<dyn PluginFunction> {
     ///         Box::new(DistanceFunction())
     ///     }
+    ///
+    ///     fn input_types(&self) -> Box<[std::any::TypeId]> {
+    ///         vec![std::any::TypeId::of::<FLOAT>(),
+    ///              std::any::TypeId::of::<FLOAT>(),
+    ///              std::any::TypeId::of::<FLOAT>(),
+    ///              std::any::TypeId::of::<FLOAT>()].into_boxed_slice()
+    ///     }
     /// }
     ///
     /// // A simple custom plugin. This should not usually be done with hand-written code.

src/lib.rs

@@ -98,6 +98,8 @@ pub use syntax::{EvalContext, Expression};
 pub use token::Position;
 pub use utils::calc_fn_spec as calc_fn_hash;
 
+pub use rhai_codegen::*;
+
 #[cfg(not(feature = "no_function"))]
 pub use parser::FnAccess;
 

src/plugin.rs

@@ -1,6 +1,6 @@
 //! Module defining plugins in Rhai. Is exported for use by plugin authors.
 
-use crate::stdlib::boxed::Box;
+use crate::stdlib::{any::TypeId, boxed::Box};
 
 pub use crate::any::{Dynamic, Variant};
 pub use crate::fn_native::{CallableFunction, FnCallArgs, IteratorFn};
@@ -38,7 +38,9 @@ pub trait PluginFunction {
     fn is_method_call(&self) -> bool;
     fn is_varadic(&self) -> bool;
 
-    fn call(&self, args: &[&mut Dynamic], pos: Position) -> Result<Dynamic, Box<EvalAltResult>>;
+    fn call(&self, args: &mut[&mut Dynamic], pos: Position) -> Result<Dynamic, Box<EvalAltResult>>;
 
     fn clone_boxed(&self) -> Box<dyn PluginFunction>;
+
+    fn input_types(&self) -> Box<[TypeId]>;
 }