Add type alias support for plugin modules.

src/types/custom_types.rs

@@ -0,0 +1,43 @@
+//! Collection of custom types.
+
+use crate::Identifier;
+use std::{any::type_name, collections::BTreeMap, fmt};
+
+/// _(internals)_ A custom type.
+/// Exported under the `internals` feature only.
+pub type CustomType = Identifier;
+
+/// _(internals)_ A collection of custom types.
+/// Exported under the `internals` feature only.
+#[derive(Clone, Hash, Default)]
+pub struct CustomTypesCollection(BTreeMap<Identifier, CustomType>);
+
+impl fmt::Debug for CustomTypesCollection {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("CustomTypesCollection ")?;
+        f.debug_map().entries(self.0.iter()).finish()
+    }
+}
+
+impl CustomTypesCollection {
+    /// Create a new [`CustomTypesCollection`].
+    #[inline(always)]
+    pub fn new() -> Self {
+        Self(BTreeMap::new())
+    }
+    /// Register a custom type.
+    #[inline(always)]
+    pub fn add(&mut self, key: impl Into<Identifier>, name: impl Into<Identifier>) {
+        self.0.insert(key.into(), name.into());
+    }
+    /// Register a custom type.
+    #[inline(always)]
+    pub fn add_type<T>(&mut self, name: &str) {
+        self.0.insert(type_name::<T>().into(), name.into());
+    }
+    /// Find a custom type.
+    #[inline(always)]
+    pub fn get(&self, key: &str) -> Option<&str> {
+        self.0.get(key).map(CustomType::as_str)
+    }
+}

src/types/dynamic.rs

@@ -1,4 +1,5 @@
-//! Helper module which defines the [`Any`] trait to to allow dynamic value handling.
+//! Helper module which defines the [`Dynamic`] data type and the
+//! [`Any`] trait to to allow custom type handling.
 
 use crate::func::native::SendSync;
 use crate::{reify, ExclusiveRange, FnPtr, ImmutableString, InclusiveRange, INT};

src/types/mod.rs

@@ -1,5 +1,6 @@
 //! Module defining Rhai data types.
 
+pub mod custom_types;
 pub mod dynamic;
 pub mod error;
 pub mod fn_ptr;
@@ -8,6 +9,7 @@ pub mod interner;
 pub mod parse_error;
 pub mod scope;
 
+pub use custom_types::{CustomType, CustomTypesCollection};
 pub use dynamic::Dynamic;
 #[cfg(not(feature = "no_std"))]
 pub use dynamic::Instant;