Restructure code base.

src/func/func.rs

@@ -0,0 +1,118 @@
+//! Module which defines the function registration mechanism.
+
+#![cfg(not(feature = "no_function"))]
+#![allow(non_snake_case)]
+
+use crate::types::dynamic::Variant;
+use crate::{Engine, EvalAltResult, ParseError, Scope, SmartString, AST};
+#[cfg(feature = "no_std")]
+use std::prelude::v1::*;
+
+/// Trait to create a Rust closure from a script.
+///
+/// Not available under `no_function`.
+pub trait Func<ARGS, RET> {
+    type Output;
+
+    /// Create a Rust closure from an [`AST`].
+    ///
+    /// The [`Engine`] and [`AST`] are consumed and basically embedded into the closure.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
+    /// use rhai::{Engine, Func};               // use 'Func' for 'create_from_ast'
+    ///
+    /// let engine = Engine::new();             // create a new 'Engine' just for this
+    ///
+    /// let ast = engine.compile("fn calc(x, y) { x + len(y) < 42 }")?;
+    ///
+    /// // Func takes two type parameters:
+    /// //   1) a tuple made up of the types of the script function's parameters
+    /// //   2) the return type of the script function
+    ///
+    /// // 'func' will have type Box<dyn Fn(i64, String) -> Result<bool, Box<EvalAltResult>>> and is callable!
+    /// let func = Func::<(i64, &str), bool>::create_from_ast(
+    /// //                ^^^^^^^^^^^ function parameter types in tuple
+    ///
+    ///                                             engine, // the 'Engine' is consumed into the closure
+    ///                                             ast,    // the 'AST'
+    ///                                             "calc"  // the entry-point function name
+    ///                                         );
+    ///
+    /// func(123, "hello")? == false;           // call the anonymous function
+    /// # Ok(())
+    /// # }
+    fn create_from_ast(self, ast: AST, entry_point: &str) -> Self::Output;
+
+    /// Create a Rust closure from a script.
+    ///
+    /// The [`Engine`] is consumed and basically embedded into the closure.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
+    /// use rhai::{Engine, Func};               // use 'Func' for 'create_from_script'
+    ///
+    /// let engine = Engine::new();             // create a new 'Engine' just for this
+    ///
+    /// let script = "fn calc(x, y) { x + len(y) < 42 }";
+    ///
+    /// // Func takes two type parameters:
+    /// //   1) a tuple made up of the types of the script function's parameters
+    /// //   2) the return type of the script function
+    ///
+    /// // 'func' will have type Box<dyn Fn(i64, String) -> Result<bool, Box<EvalAltResult>>> and is callable!
+    /// let func = Func::<(i64, &str), bool>::create_from_script(
+    /// //                ^^^^^^^^^^^ function parameter types in tuple
+    ///
+    ///                                             engine, // the 'Engine' is consumed into the closure
+    ///                                             script, // the script, notice number of parameters must match
+    ///                                             "calc"  // the entry-point function name
+    ///                                         )?;
+    ///
+    /// func(123, "hello")? == false;           // call the anonymous function
+    /// # Ok(())
+    /// # }
+    /// ```
+    fn create_from_script(
+        self,
+        script: &str,
+        entry_point: &str,
+    ) -> Result<Self::Output, ParseError>;
+}
+
+macro_rules! def_anonymous_fn {
+    () => {
+        def_anonymous_fn!(imp);
+    };
+    (imp $($par:ident),*) => {
+        impl<$($par: Variant + Clone,)* RET: Variant + Clone> Func<($($par,)*), RET> for Engine
+        {
+            #[cfg(feature = "sync")]
+            type Output = Box<dyn Fn($($par),*) -> Result<RET, Box<EvalAltResult>> + Send + Sync>;
+            #[cfg(not(feature = "sync"))]
+            type Output = Box<dyn Fn($($par),*) -> Result<RET, Box<EvalAltResult>>>;
+
+            #[inline]
+            fn create_from_ast(self, ast: AST, entry_point: &str) -> Self::Output {
+                let fn_name: SmartString = entry_point.into();
+                Box::new(move |$($par),*| self.call_fn(&mut Scope::new(), &ast, &fn_name, ($($par,)*)))
+            }
+
+            #[inline]
+            fn create_from_script(self, script: &str, entry_point: &str) -> Result<Self::Output, ParseError> {
+                let ast = self.compile(script)?;
+                Ok(Func::<($($par,)*), RET>::create_from_ast(self, ast, entry_point))
+            }
+        }
+    };
+    ($p0:ident $(, $p:ident)*) => {
+        def_anonymous_fn!(imp $p0 $(, $p)*);
+        def_anonymous_fn!($($p),*);
+    };
+}
+
+def_anonymous_fn!(A, B, C, D, E, F, G, H, J, K, L, M, N, P, Q, R, S, T, U, V);