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[WIP] Supports enum_primitive! with ToPrimitive support. #5

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[WIP] Supports enum_primitive! with ToPrimitive support. #5

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144 changes: 144 additions & 0 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,7 @@ extern crate num;

pub use std::option::Option;
pub use num::FromPrimitive;
pub use num::ToPrimitive;

/// Helper macro for internal use by `enum_from_primitive!`.
#[macro_export]
Expand All @@ -73,6 +74,30 @@ macro_rules! enum_from_primitive_impl_ty {
};
}

/// Helper macro for internal use by `enum_to_primitive!`.
#[macro_export]
macro_rules! enum_to_primitive_impl_ty {
($meth:ident, $ty:ty, $name:ident) => {
#[allow(non_upper_case_globals, unused)]
fn $meth(&self) -> $crate::Option<$ty> {
let copy: $name = unsafe { ::std::mem::transmute_copy(self) };
Some(copy as $ty)
}
};
}

/// Helper macro for internal use by `enum_to_primitive!`.
#[macro_export]
#[macro_use(enum_to_primitive_impl_ty)]
macro_rules! enum_to_primitive_impl {
($name:ident) => {
impl $crate::ToPrimitive for $name {
enum_to_primitive_impl_ty! { to_i64, i64, $name }
enum_to_primitive_impl_ty! { to_u64, u64, $name }
}
};
}

/// Helper macro for internal use by `enum_from_primitive!`.
#[macro_export]
#[macro_use(enum_from_primitive_impl_ty)]
Expand Down Expand Up @@ -194,3 +219,122 @@ macro_rules! enum_from_primitive {
enum_from_primitive_impl! { $name, $( $( $variant )+ )+ }
};
}


/// Wrap this macro around an `enum` declaration to get an
/// automatically generated implementation of `num::FromPrimitive`.
#[macro_export]
#[macro_use(enum_primitive_impl)]
macro_rules! enum_primitive {
(
$( #[$enum_attr:meta] )*
enum $name:ident {
$( $( #[$variant_attr:meta] )* $variant:ident ),+ $( = $discriminator:expr, $( $( #[$variant_two_attr:meta] )* $variant_two:ident ),+ )*
}
) => {
$( #[$enum_attr] )*
enum $name {
$( $( #[$variant_attr] )* $variant ),+ $( = $discriminator, $( $( #[$variant_two_attr] )* $variant_two ),+ )*
}
enum_from_primitive_impl! { $name, $( $variant )+ $( $( $variant_two )+ )* }
enum_to_primitive_impl! { $name }
};

(
$( #[$enum_attr:meta] )*
enum $name:ident {
$( $( $( #[$variant_attr:meta] )* $variant:ident ),+ = $discriminator:expr ),*
}
) => {
$( #[$enum_attr] )*
enum $name {
$( $( $( #[$variant_attr] )* $variant ),+ = $discriminator ),*
}
enum_from_primitive_impl! { $name, $( $( $variant )+ )* }
enum_to_primitive_impl! { $name }
};

(
$( #[$enum_attr:meta] )*
enum $name:ident {
$( $( #[$variant_attr:meta] )* $variant:ident ),+ $( = $discriminator:expr, $( $( #[$variant_two_attr:meta] )* $variant_two:ident ),+ )*,
}
) => {
$( #[$enum_attr] )*
enum $name {
$( $( #[$variant_attr] )* $variant ),+ $( = $discriminator, $( $( #[$variant_two_attr] )* $variant_two ),+ )*,
}
enum_from_primitive_impl! { $name, $( $variant )+ $( $( $variant_two )+ )* }
enum_to_primitive_impl! { $name }
};

(
$( #[$enum_attr:meta] )*
enum $name:ident {
$( $( $( #[$variant_attr:meta] )* $variant:ident ),+ = $discriminator:expr ),+,
}
) => {
$( #[$enum_attr] )*
enum $name {
$( $( $( #[$variant_attr] )* $variant ),+ = $discriminator ),+,
}
enum_from_primitive_impl! { $name, $( $( $variant )+ )+ }
enum_to_primitive_impl! { $name }
};

(
$( #[$enum_attr:meta] )*
pub enum $name:ident {
$( $( #[$variant_attr:meta] )* $variant:ident ),+ $( = $discriminator:expr, $( $( #[$variant_two_attr:meta] )* $variant_two:ident ),+ )*
}
) => {
$( #[$enum_attr] )*
pub enum $name {
$( $( #[$variant_attr] )* $variant ),+ $( = $discriminator, $( $( #[$variant_two_attr] )* $variant_two ),+ )*
}
enum_from_primitive_impl! { $name, $( $variant )+ $( $( $variant_two )+ )* }
enum_to_primitive_impl! { $name }
};

(
$( #[$enum_attr:meta] )*
pub enum $name:ident {
$( $( $( #[$variant_attr:meta] )* $variant:ident ),+ = $discriminator:expr ),*
}
) => {
$( #[$enum_attr] )*
pub enum $name {
$( $( $( #[$variant_attr] )* $variant ),+ = $discriminator ),*
}
enum_from_primitive_impl! { $name, $( $( $variant )+ )* }
enum_to_primitive_impl! { $name }
};

(
$( #[$enum_attr:meta] )*
pub enum $name:ident {
$( $( #[$variant_attr:meta] )* $variant:ident ),+ $( = $discriminator:expr, $( $( #[$variant_two_attr:meta] )* $variant_two:ident ),+ )*,
}
) => {
$( #[$enum_attr] )*
pub enum $name {
$( $( #[$variant_attr] )* $variant ),+ $( = $discriminator, $( $( #[$variant_two_attr] )* $variant_two ),+ )*,
}
enum_from_primitive_impl! { $name, $( $variant )+ $( $( $variant_two )+ )* }
enum_to_primitive_impl! { $name }
};

(
$( #[$enum_attr:meta] )*
pub enum $name:ident {
$( $( $( #[$variant_attr:meta] )* $variant:ident ),+ = $discriminator:expr ),+,
}
) => {
$( #[$enum_attr] )*
pub enum $name {
$( $( $( #[$variant_attr] )* $variant ),+ = $discriminator ),+,
}
enum_from_primitive_impl! { $name, $( $( $variant )+ )+ }
enum_to_primitive_impl! { $name }
};
}
50 changes: 50 additions & 0 deletions tests/tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -233,3 +233,53 @@ fn documented() {
assert_eq!(Documented::from_i32(17), Some(Documented::A));
assert_eq!(Documented::from_i32(91), None);
}

#[test]
fn to_primitive() {
use ep::ToPrimitive;

mod top {
enum_primitive! {
#[derive(Debug, PartialEq)]
#[repr(u64)]
pub enum EnumU64 {
A = 0xdeadbeefdeadbeef,
B = 0x0,
}
}

enum_primitive! {
#[derive(Debug, PartialEq)]
#[repr(u32)]
pub enum EnumU32 {
A = 0xdeadbeef,
B = 0x0,
}
}

enum_primitive! {
#[derive(Debug, PartialEq)]
#[repr(u16)]
pub enum EnumU16 {
A = 0xdead,
B = 0x0,
}
}

enum_primitive! {
#[derive(Debug, PartialEq)]
#[repr(u8)]
pub enum EnumU8 {
A = 0xde,
B = 0x0,
}
}
}

println!("what {:?}", top::EnumU8::A.to_u8());

assert_eq!(0xdeadbeefdeadbeef, top::EnumU64::A.to_u64().unwrap());
assert_eq!(0xdeadbeef, top::EnumU32::A.to_u32().unwrap());
assert_eq!(0xdead, top::EnumU16::A.to_u16().unwrap());
assert_eq!(0xde, top::EnumU8::A.to_u8().unwrap());
}