Restructure code base.

src/func/plugin.rs

@@ -0,0 +1,30 @@
+//! Module defining macros for developing _plugins_.
+
+use super::call::FnCallArgs;
+pub use super::native::CallableFunction;
+pub use crate::{
+    Dynamic, Engine, EvalAltResult, FnAccess, FnNamespace, ImmutableString, Module,
+    NativeCallContext, Position,
+};
+#[cfg(feature = "no_std")]
+use std::prelude::v1::*;
+pub use std::{any::TypeId, mem};
+pub type RhaiResult = Result<Dynamic, Box<EvalAltResult>>;
+
+#[cfg(not(features = "no_module"))]
+pub use rhai_codegen::*;
+#[cfg(features = "no_module")]
+pub use rhai_codegen::{export_fn, register_exported_fn};
+
+/// Trait implemented by a _plugin function_.
+///
+/// This trait should not be used directly.
+/// Use the `#[export_module]` and `#[export_fn]` procedural attributes instead.
+pub trait PluginFunction {
+    /// Call the plugin function with the arguments provided.
+    fn call(&self, context: NativeCallContext, args: &mut FnCallArgs) -> RhaiResult;
+
+    /// Is this plugin function a method?
+    #[must_use]
+    fn is_method_call(&self) -> bool;
+}