Improve docs.

src/api/build_type.rs

@@ -128,11 +128,11 @@ impl<'a, T: Variant + Clone> TypeBuilder<'a, T> {
 
     /// Register a custom function.
     #[inline(always)]
-    pub fn with_fn<N, A, F, R, S>(&mut self, name: N, method: F) -> &mut Self
+    pub fn with_fn<A, R, S>(
-    where
+        &mut self,
-        N: AsRef<str> + Into<Identifier>,
+        name: impl AsRef<str> + Into<Identifier>,
-        F: RegisterNativeFunction<A, R, S>,
+        method: impl RegisterNativeFunction<A, R, S>,
-    {
+    ) -> &mut Self {
         self.engine.register_fn(name, method);
         self
     }

src/api/deprecated.rs

@@ -143,11 +143,11 @@ impl Engine {
     /// This method will be removed in the next major version.
     #[deprecated(since = "1.9.1", note = "use `register_fn` instead")]
     #[inline(always)]
-    pub fn register_result_fn<N, A, F, R, S>(&mut self, name: N, func: F) -> &mut Self
+    pub fn register_result_fn<A, R, S>(
-    where
+        &mut self,
-        N: AsRef<str> + Into<Identifier>,
+        name: impl AsRef<str> + Into<Identifier>,
-        F: RegisterNativeFunction<A, R, RhaiResultOf<S>>,
+        func: impl RegisterNativeFunction<A, R, RhaiResultOf<S>>,
-    {
+    ) -> &mut Self {
         self.register_fn(name, func)
     }
     /// Register a getter function for a member of a registered type with the [`Engine`].

src/api/register.rs

@@ -53,11 +53,11 @@ impl Engine {
     /// # }
     /// ```
     #[inline]
-    pub fn register_fn<N, A, F, R, S>(&mut self, name: N, func: F) -> &mut Self
+    pub fn register_fn<A, R, S, F: RegisterNativeFunction<A, R, S>>(
-    where
+        &mut self,
-        N: AsRef<str> + Into<Identifier>,
+        name: impl AsRef<str> + Into<Identifier>,
-        F: RegisterNativeFunction<A, R, S>,
+        func: F,
-    {
+    ) -> &mut Self {
         let param_types = F::param_types();
 
         #[cfg(feature = "metadata")]
@@ -109,16 +109,12 @@ impl Engine {
     ///
     /// To access the first mutable parameter, use `args.get_mut(0).unwrap()`
     #[inline(always)]
-    pub fn register_raw_fn<N, T>(
+    pub fn register_raw_fn<T: Variant + Clone>(
         &mut self,
-        name: N,
+        name: impl AsRef<str> + Into<Identifier>,
         arg_types: impl AsRef<[TypeId]>,
         func: impl Fn(NativeCallContext, &mut FnCallArgs) -> RhaiResultOf<T> + SendSync + 'static,
-    ) -> &mut Self
+    ) -> &mut Self {
-    where
-        N: AsRef<str> + Into<Identifier>,
-        T: Variant + Clone,
-    {
         self.global_namespace_mut().set_raw_fn(
             name,
             FnNamespace::Global,

src/func/register.rs

@@ -11,20 +11,23 @@ use crate::{reify, Dynamic, NativeCallContext, RhaiResultOf};
 use std::prelude::v1::*;
 use std::{any::TypeId, mem};
 
-// These types are used to build a unique _marker_ tuple type for each combination
+/// These types are used to build a unique _marker_ tuple type for each combination
-// of function parameter types in order to make each trait implementation unique.
+/// of function parameter types in order to make each trait implementation unique.
-// That is because stable Rust currently does not allow distinguishing implementations
+///
-// based purely on parameter types of traits (`Fn`, `FnOnce` and `FnMut`).
+/// That is because stable Rust currently does not allow distinguishing implementations
-//
+/// based purely on parameter types of traits (`Fn`, `FnOnce` and `FnMut`).
-// For example:
+///
-//
+/// # Examples
-// `NativeFunction<(Mut<A>, B, Ref<C>), R>`
+///
-//
+/// `RegisterNativeFunction<(Mut<A>, B, Ref<C>), R, ()>` = `Fn(&mut A, B, &C) -> R`
-// will have the function prototype constraint to:
+///
-//
+/// `RegisterNativeFunction<(Mut<A>, B, Ref<C>), R, NativeCallContext>` = `Fn(NativeCallContext, &mut A, B, &C) -> R`
-// `FN: (&mut A, B, &C) -> R`
+///
-//
+/// `RegisterNativeFunction<(Mut<A>, B, Ref<C>), R, RhaiResultOf<()>>` = `Fn(&mut A, B, &C) -> Result<R, Box<EvalAltResult>>`
-// These types are not actually used anywhere.
+///
+/// `RegisterNativeFunction<(Mut<A>, B, Ref<C>), R, RhaiResultOf<NativeCallContext>>` = `Fn(NativeCallContext, &mut A, B, &C) -> Result<R, Box<EvalAltResult>>`
+///
+/// These types are not actually used anywhere.
 pub struct Mut<T>(T);
 //pub struct Ref<T>(T);
 
@@ -60,6 +63,11 @@ pub fn by_value<T: Variant + Clone>(data: &mut Dynamic) -> T {
 }
 
 /// Trait to register custom Rust functions.
+///
+/// # Type Parameters
+///
+/// * `ARGS` - a tuple containing parameter types, with `&mut T` represented by [`Mut<T>`].
+/// * `RET` - return type of the function; if the function returns `Result`, it is the unwrapped inner value type.
 pub trait RegisterNativeFunction<ARGS, RET, RESULT> {
     /// Convert this function into a [`CallableFunction`].
     #[must_use]

src/module/mod.rs

@@ -1245,18 +1245,14 @@ impl Module {
     /// assert!(module.contains_fn(hash));
     /// ```
     #[inline(always)]
-    pub fn set_raw_fn<T, F>(
+    pub fn set_raw_fn<T: Variant + Clone>(
         &mut self,
         name: impl AsRef<str>,
         namespace: FnNamespace,
         access: FnAccess,
         arg_types: impl AsRef<[TypeId]>,
-        func: F,
+        func: impl Fn(NativeCallContext, &mut FnCallArgs) -> RhaiResultOf<T> + SendSync + 'static,
-    ) -> u64
+    ) -> u64 {
-    where
-        T: Variant + Clone,
-        F: Fn(NativeCallContext, &mut FnCallArgs) -> RhaiResultOf<T> + SendSync + 'static,
-    {
         let f =
             move |ctx: NativeCallContext, args: &mut FnCallArgs| func(ctx, args).map(Dynamic::from);
 
@@ -1293,11 +1289,14 @@ impl Module {
     /// assert!(module.contains_fn(hash));
     /// ```
     #[inline(always)]
-    pub fn set_native_fn<ARGS, N, T, F, S>(&mut self, name: N, func: F) -> u64
+    pub fn set_native_fn<A, T, F, S>(
+        &mut self,
+        name: impl AsRef<str> + Into<Identifier>,
+        func: F,
+    ) -> u64
     where
-        N: AsRef<str> + Into<Identifier>,
         T: Variant + Clone,
-        F: RegisterNativeFunction<ARGS, T, RhaiResultOf<S>>,
+        F: RegisterNativeFunction<A, T, RhaiResultOf<S>>,
     {
         self.set_fn(
             name,
@@ -1587,16 +1586,17 @@ impl Module {
     /// ```
     #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
     #[inline(always)]
-    pub fn set_indexer_get_set_fn<A, B, T, S1, S2>(
+    pub fn set_indexer_get_set_fn<
-        &mut self,
-        get_fn: impl RegisterNativeFunction<(Mut<A>, B), T, RhaiResultOf<S1>> + SendSync + 'static,
-        set_fn: impl RegisterNativeFunction<(Mut<A>, B, T), (), RhaiResultOf<S2>> + SendSync + 'static,
-    ) -> (u64, u64)
-    where
         A: Variant + Clone,
         B: Variant + Clone,
         T: Variant + Clone,
-    {
+        S1,
+        S2,
+    >(
+        &mut self,
+        get_fn: impl RegisterNativeFunction<(Mut<A>, B), T, RhaiResultOf<S1>> + SendSync + 'static,
+        set_fn: impl RegisterNativeFunction<(Mut<A>, B, T), (), RhaiResultOf<S2>> + SendSync + 'static,
+    ) -> (u64, u64) {
         (
             self.set_indexer_get_fn(get_fn),
             self.set_indexer_set_fn(set_fn),

src/serde/de.rs

@@ -515,41 +515,31 @@ impl<'a: 'de, 'de, ITER: Iterator<Item = &'a Dynamic>> serde::de::SeqAccess<'de>
 
 /// `MapAccess` implementation for maps.
 #[cfg(not(feature = "no_object"))]
-struct IterateMap<'a, KEYS, VALUES>
+struct IterateMap<'a, K: Iterator<Item = &'a str>, V: Iterator<Item = &'a Dynamic>> {
-where
-    KEYS: Iterator<Item = &'a str>,
-    VALUES: Iterator<Item = &'a Dynamic>,
-{
     // Iterator for a stream of [`Dynamic`][crate::Dynamic] keys.
-    keys: KEYS,
+    keys: K,
     // Iterator for a stream of [`Dynamic`][crate::Dynamic] values.
-    values: VALUES,
+    values: V,
 }
 
 #[cfg(not(feature = "no_object"))]
-impl<'a, KEYS, VALUES> IterateMap<'a, KEYS, VALUES>
+impl<'a, K: Iterator<Item = &'a str>, V: Iterator<Item = &'a Dynamic>> IterateMap<'a, K, V> {
-where
-    KEYS: Iterator<Item = &'a str>,
-    VALUES: Iterator<Item = &'a Dynamic>,
-{
     #[must_use]
-    pub fn new(keys: KEYS, values: VALUES) -> Self {
+    pub fn new(keys: K, values: V) -> Self {
         Self { keys, values }
     }
 }
 
 #[cfg(not(feature = "no_object"))]
-impl<'a: 'de, 'de, KEYS, VALUES> serde::de::MapAccess<'de> for IterateMap<'a, KEYS, VALUES>
+impl<'a: 'de, 'de, K: Iterator<Item = &'a str>, V: Iterator<Item = &'a Dynamic>>
-where
+    serde::de::MapAccess<'de> for IterateMap<'a, K, V>
-    KEYS: Iterator<Item = &'a str>,
-    VALUES: Iterator<Item = &'a Dynamic>,
 {
     type Error = RhaiError;
 
-    fn next_key_seed<K: serde::de::DeserializeSeed<'de>>(
+    fn next_key_seed<S: serde::de::DeserializeSeed<'de>>(
         &mut self,
-        seed: K,
+        seed: S,
-    ) -> RhaiResultOf<Option<K::Value>> {
+    ) -> RhaiResultOf<Option<S::Value>> {
         // Deserialize each `Identifier` key coming out of the keys iterator.
         match self.keys.next() {
             None => Ok(None),
@@ -559,10 +549,10 @@ where
         }
     }
 
-    fn next_value_seed<V: serde::de::DeserializeSeed<'de>>(
+    fn next_value_seed<S: serde::de::DeserializeSeed<'de>>(
         &mut self,
-        seed: V,
+        seed: S,
-    ) -> RhaiResultOf<V::Value> {
+    ) -> RhaiResultOf<S::Value> {
         // Deserialize each value item coming out of the iterator.
         seed.deserialize(&mut DynamicDeserializer::from_dynamic(
             self.values.next().unwrap(),