Auto merge of #525 - serde-rs:forward, r=oli-obk

Expose forward_to_deserialize macro

Fixes #522.

```rust
impl Deserializer for MyDeserializer {
    fn deserialize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
        where V: Visitor
    {
        /* ... */
    }

    forward_to_deserialize! {
        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
        tuple_struct struct struct_field tuple enum ignored_any
    }
}
```

cc @nox

serde/src/de/mod.rs

@@ -11,71 +11,6 @@ use collections::{String, Vec};
 use core::fmt;
 
 ///////////////////////////////////////////////////////////////////////////////
-/// Macro helper to not have to re-implement all the defaulted methods.
-/// Every given method ignores all arguments and forwards to `deserialize`.
-/// Note that `deserialize_enum` simply returns an `Error::invalid_type`.
-macro_rules! de_forward_to_deserialize {
-    ($($func:ident),*) => {
-        $(de_forward_to_deserialize!{func: $func})*
-    };
-    (func: deserialize_unit_struct) => {
-        de_forward_to_deserialize!{named: deserialize_unit_struct}
-    };
-    (func: deserialize_newtype_struct) => {
-        de_forward_to_deserialize!{named: deserialize_newtype_struct}
-    };
-    (func: deserialize_tuple) => {
-        de_forward_to_deserialize!{tup_fn: deserialize_tuple}
-    };
-    (func: deserialize_seq_fixed_size) => {
-        de_forward_to_deserialize!{tup_fn: deserialize_seq_fixed_size}
-    };
-    (func: deserialize_tuple_struct) => {
-        #[inline]
-        fn deserialize_tuple_struct<__V>(&mut self, _: &str, _: usize, visitor: __V) -> Result<__V::Value, Self::Error>
-            where __V: $crate::de::Visitor {
-            self.deserialize(visitor)
-        }
-    };
-    (func: deserialize_struct) => {
-        #[inline]
-        fn deserialize_struct<__V>(&mut self, _: &str, _: &[&str], visitor: __V) -> Result<__V::Value, Self::Error>
-            where __V: $crate::de::Visitor {
-            self.deserialize(visitor)
-        }
-    };
-    (func: deserialize_enum) => {
-        #[inline]
-        fn deserialize_enum<__V>(&mut self, _: &str, _: &[&str], _: __V) -> Result<__V::Value, Self::Error>
-            where __V: $crate::de::EnumVisitor {
-            Err($crate::de::Error::invalid_type($crate::de::Type::Enum))
-        }
-    };
-    (named: $func:ident) => {
-        #[inline]
-        fn $func<__V>(&mut self, _: &str, visitor: __V) -> Result<__V::Value, Self::Error>
-            where __V: $crate::de::Visitor {
-            self.deserialize(visitor)
-        }
-    };
-    (tup_fn: $func: ident) => {
-        #[inline]
-        fn $func<__V>(&mut self, _: usize, visitor: __V) -> Result<__V::Value, Self::Error>
-            where __V: $crate::de::Visitor {
-            self.deserialize(visitor)
-        }
-    };
-    (func: $func:ident) => {
-        #[inline]
-        fn $func<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-            where __V: $crate::de::Visitor {
-            self.deserialize(visitor)
-        }
-    };
-}
-
-///////////////////////////////////////////////////////////////////////////////
-// modules come after macros
 
 pub mod impls;
 pub mod value;

serde/src/de/value.rs

@@ -178,20 +178,10 @@ impl<E> de::Deserializer for UnitDeserializer<E>
 {
     type Error = E;
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit seq seq_fixed_size bytes map unit_struct newtype_struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        tuple_struct struct struct_field tuple enum ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit,
-        deserialize_seq, deserialize_seq_fixed_size,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_enum,
-        deserialize_struct, deserialize_tuple_struct
     }
 
     fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
@@ -229,21 +219,11 @@ macro_rules! primitive_deserializer {
         {
             type Error = E;
 
-            de_forward_to_deserialize!{
+            forward_to_deserialize! {
-                deserialize_bool,
+                bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str
-                deserialize_f64, deserialize_f32,
+                string unit option seq seq_fixed_size bytes map unit_struct
-                deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+                newtype_struct tuple_struct struct struct_field tuple enum
-                deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
+                ignored_any
-                deserialize_char, deserialize_str, deserialize_string,
-                deserialize_ignored_any,
-                deserialize_bytes,
-                deserialize_unit_struct, deserialize_unit,
-                deserialize_seq, deserialize_seq_fixed_size,
-                deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-                deserialize_tuple,
-                deserialize_enum,
-                deserialize_struct, deserialize_tuple_struct,
-                deserialize_option
             }
 
             fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
@@ -311,20 +291,10 @@ impl<'a, E> de::Deserializer for StrDeserializer<'a, E>
         visitor.visit(self)
     }
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        tuple_struct struct struct_field tuple ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit,
-        deserialize_seq, deserialize_seq_fixed_size,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_struct, deserialize_tuple_struct,
-        deserialize_option
     }
 }
 
@@ -408,20 +378,10 @@ impl<E> de::Deserializer for StringDeserializer<E>
         visitor.visit(self)
     }
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        tuple_struct struct struct_field tuple ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit,
-        deserialize_seq, deserialize_seq_fixed_size,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_struct, deserialize_tuple_struct,
-        deserialize_option
     }
 }
 
@@ -507,20 +467,10 @@ impl<'a, E> de::Deserializer for CowStrDeserializer<'a, E>
         visitor.visit(self)
     }
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        tuple_struct struct struct_field tuple ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit,
-        deserialize_seq, deserialize_seq_fixed_size,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_struct, deserialize_tuple_struct,
-        deserialize_option
     }
 }
 
@@ -599,21 +549,10 @@ impl<I, T, E> de::Deserializer for SeqDeserializer<I, E>
         visitor.visit_seq(self)
     }
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        tuple_struct struct struct_field tuple enum ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit,
-        deserialize_seq, deserialize_seq_fixed_size,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_enum,
-        deserialize_struct, deserialize_tuple_struct,
-        deserialize_option
     }
 }
 
@@ -722,21 +661,10 @@ impl<V_, E> de::Deserializer for SeqVisitorDeserializer<V_, E>
         visitor.visit_seq(&mut self.visitor)
     }
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        tuple_struct struct struct_field tuple enum ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit,
-        deserialize_seq, deserialize_seq_fixed_size,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_enum,
-        deserialize_struct, deserialize_tuple_struct,
-        deserialize_option
     }
 }
 
@@ -822,20 +750,10 @@ impl<I, K, V, E> de::Deserializer for MapDeserializer<I, K, V, E>
         }
     }
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit option bytes map unit_struct newtype_struct tuple_struct struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        struct_field tuple enum ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_enum,
-        deserialize_struct, deserialize_tuple_struct,
-        deserialize_option
     }
 }
 
@@ -928,19 +846,10 @@ impl<A, B, E> de::Deserializer for PairDeserializer<A, B, E>
 {
     type Error = E;
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit option bytes map unit_struct newtype_struct tuple_struct struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        struct_field tuple enum ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit, deserialize_option,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_enum,
-        deserialize_struct, deserialize_tuple_struct
     }
 
     fn deserialize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
@@ -1075,21 +984,10 @@ impl<V_, E> de::Deserializer for MapVisitorDeserializer<V_, E>
         visitor.visit_map(&mut self.visitor)
     }
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        tuple_struct struct struct_field tuple enum ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit,
-        deserialize_seq, deserialize_seq_fixed_size,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_enum,
-        deserialize_struct, deserialize_tuple_struct,
-        deserialize_option
     }
 }
 
@@ -1122,25 +1020,13 @@ impl<'a, E> de::Deserializer for BytesDeserializer<'a, E>
         }
     }
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        tuple_struct struct struct_field tuple enum ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit,
-        deserialize_seq, deserialize_seq_fixed_size,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_enum,
-        deserialize_struct, deserialize_tuple_struct,
-        deserialize_option
     }
 }
 
-
 ///////////////////////////////////////////////////////////////////////////////
 
 #[cfg(any(feature = "std", feature = "collections"))]
@@ -1173,20 +1059,9 @@ impl<E> de::Deserializer for ByteBufDeserializer<E>
         }
     }
 
-    de_forward_to_deserialize!{
+    forward_to_deserialize! {
-        deserialize_bool,
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
-        deserialize_f64, deserialize_f32,
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
-        deserialize_u8, deserialize_u16, deserialize_u32, deserialize_u64, deserialize_usize,
+        tuple_struct struct struct_field tuple enum ignored_any
-        deserialize_i8, deserialize_i16, deserialize_i32, deserialize_i64, deserialize_isize,
-        deserialize_char, deserialize_str, deserialize_string,
-        deserialize_ignored_any,
-        deserialize_bytes,
-        deserialize_unit_struct, deserialize_unit,
-        deserialize_seq, deserialize_seq_fixed_size,
-        deserialize_map, deserialize_newtype_struct, deserialize_struct_field,
-        deserialize_tuple,
-        deserialize_enum,
-        deserialize_struct, deserialize_tuple_struct,
-        deserialize_option
     }
 }

serde/src/lib.rs

@@ -45,6 +45,9 @@ macro_rules! format {
     ($s:expr, $($rest:tt)*) => ($s)
 }
 
+#[macro_use]
+mod macros;
+
 pub mod bytes;
 pub mod de;
 #[cfg(feature = "std")]

serde/src/macros.rs

@@ -0,0 +1,179 @@
+#[cfg(feature = "std")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! forward_to_deserialize_method {
+    ($func:ident($($arg:ty),*)) => {
+        #[inline]
+        fn $func<__V>(&mut self, $(_: $arg,)* visitor: __V) -> ::std::result::Result<__V::Value, Self::Error>
+            where __V: $crate::de::Visitor
+        {
+            self.deserialize(visitor)
+        }
+    };
+}
+
+#[cfg(not(feature = "std"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! forward_to_deserialize_method {
+    ($func:ident($($arg:ty),*)) => {
+        #[inline]
+        fn $func<__V>(&mut self, $(_: $arg,)* visitor: __V) -> ::core::result::Result<__V::Value, Self::Error>
+            where __V: $crate::de::Visitor
+        {
+            self.deserialize(visitor)
+        }
+    };
+}
+
+#[cfg(feature = "std")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! forward_to_deserialize_enum {
+    () => {
+        #[inline]
+        fn deserialize_enum<__V>(&mut self, _: &str, _: &[&str], _: __V) -> ::std::result::Result<__V::Value, Self::Error>
+            where __V: $crate::de::EnumVisitor
+        {
+            Err($crate::de::Error::invalid_type($crate::de::Type::Enum))
+        }
+    };
+}
+
+#[cfg(not(feature = "std"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! forward_to_deserialize_enum {
+    () => {
+        #[inline]
+        fn deserialize_enum<__V>(&mut self, _: &str, _: &[&str], _: __V) -> ::core::result::Result<__V::Value, Self::Error>
+            where __V: $crate::de::EnumVisitor
+        {
+            Err($crate::de::Error::invalid_type($crate::de::Type::Enum))
+        }
+    };
+}
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! forward_to_deserialize_helper {
+    (bool) => {
+        forward_to_deserialize_method!{deserialize_bool()}
+    };
+    (usize) => {
+        forward_to_deserialize_method!{deserialize_usize()}
+    };
+    (u8) => {
+        forward_to_deserialize_method!{deserialize_u8()}
+    };
+    (u16) => {
+        forward_to_deserialize_method!{deserialize_u16()}
+    };
+    (u32) => {
+        forward_to_deserialize_method!{deserialize_u32()}
+    };
+    (u64) => {
+        forward_to_deserialize_method!{deserialize_u64()}
+    };
+    (isize) => {
+        forward_to_deserialize_method!{deserialize_isize()}
+    };
+    (i8) => {
+        forward_to_deserialize_method!{deserialize_i8()}
+    };
+    (i16) => {
+        forward_to_deserialize_method!{deserialize_i16()}
+    };
+    (i32) => {
+        forward_to_deserialize_method!{deserialize_i32()}
+    };
+    (i64) => {
+        forward_to_deserialize_method!{deserialize_i64()}
+    };
+    (f32) => {
+        forward_to_deserialize_method!{deserialize_f32()}
+    };
+    (f64) => {
+        forward_to_deserialize_method!{deserialize_f64()}
+    };
+    (char) => {
+        forward_to_deserialize_method!{deserialize_char()}
+    };
+    (str) => {
+        forward_to_deserialize_method!{deserialize_str()}
+    };
+    (string) => {
+        forward_to_deserialize_method!{deserialize_string()}
+    };
+    (unit) => {
+        forward_to_deserialize_method!{deserialize_unit()}
+    };
+    (option) => {
+        forward_to_deserialize_method!{deserialize_option()}
+    };
+    (seq) => {
+        forward_to_deserialize_method!{deserialize_seq()}
+    };
+    (seq_fixed_size) => {
+        forward_to_deserialize_method!{deserialize_seq_fixed_size(usize)}
+    };
+    (bytes) => {
+        forward_to_deserialize_method!{deserialize_bytes()}
+    };
+    (map) => {
+        forward_to_deserialize_method!{deserialize_map()}
+    };
+    (unit_struct) => {
+        forward_to_deserialize_method!{deserialize_unit_struct(&'static str)}
+    };
+    (newtype_struct) => {
+        forward_to_deserialize_method!{deserialize_newtype_struct(&'static str)}
+    };
+    (tuple_struct) => {
+        forward_to_deserialize_method!{deserialize_tuple_struct(&'static str, usize)}
+    };
+    (struct) => {
+        forward_to_deserialize_method!{deserialize_struct(&'static str, &'static [&'static str])}
+    };
+    (struct_field) => {
+        forward_to_deserialize_method!{deserialize_struct_field()}
+    };
+    (tuple) => {
+        forward_to_deserialize_method!{deserialize_tuple(usize)}
+    };
+    (ignored_any) => {
+        forward_to_deserialize_method!{deserialize_ignored_any()}
+    };
+    (enum) => {
+        forward_to_deserialize_enum!();
+    };
+}
+
+/// Helper to forward `Deserializer` methods to `Deserializer::deserialize`.
+/// Every given method ignores all arguments and forwards to `deserialize`.
+/// Note that `deserialize_enum` simply returns an `Error::invalid_type`; a
+/// better approach is tracked in [serde-rs/serde#521][1].
+///
+/// ```rust,ignore
+/// impl Deserializer for MyDeserializer {
+///     fn deserialize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+///         where V: Visitor
+///     {
+///         /* ... */
+///     }
+///
+///     forward_to_deserialize! {
+///         bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+///         unit option seq seq_fixed_size bytes map unit_struct newtype_struct
+///         tuple_struct struct struct_field tuple enum ignored_any
+///     }
+/// }
+/// ```
+///
+/// [1]: https://github.com/serde-rs/serde/issues/521
+#[macro_export]
+macro_rules! forward_to_deserialize {
+    ($($func:ident)*) => {
+        $(forward_to_deserialize_helper!{$func})*
+    };
+}