diff options
Diffstat (limited to 'rand/rand-derive/src')
| -rw-r--r-- | rand/rand-derive/src/lib.rs | 116 | 
1 files changed, 0 insertions, 116 deletions
| diff --git a/rand/rand-derive/src/lib.rs b/rand/rand-derive/src/lib.rs deleted file mode 100644 index 80c803a..0000000 --- a/rand/rand-derive/src/lib.rs +++ /dev/null @@ -1,116 +0,0 @@ -//! Support for `#[derive(Rand)]` -//! -//! # Examples -//! -//! ``` -//! extern crate rand; -//! #[macro_use] -//! extern crate rand_derive; -//! -//! #[derive(Rand, Debug)] -//! struct MyStruct { -//!     a: i32, -//!     b: u32, -//! } -//! -//! fn main() { -//!     println!("{:?}", rand::random::<MyStruct>()); -//! } -//! ``` - -extern crate proc_macro; -#[macro_use] -extern crate quote; -extern crate syn; - -use proc_macro::TokenStream; - -#[proc_macro_derive(Rand)] -pub fn rand_derive(input: TokenStream) -> TokenStream { -    let s = input.to_string(); -    let ast = syn::parse_derive_input(&s).unwrap(); -    let gen = impl_rand_derive(&ast); -    gen.parse().unwrap() -} - -fn impl_rand_derive(ast: &syn::MacroInput) -> quote::Tokens { -    let name = &ast.ident; -    let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl(); - -    let rand = match ast.body { -        syn::Body::Struct(syn::VariantData::Struct(ref body)) => { -            let fields = body -                .iter() -                .filter_map(|field| field.ident.as_ref()) -                .map(|ident| quote! { #ident: __rng.gen() }) -                .collect::<Vec<_>>(); - -            quote! { #name { #(#fields,)* } } -        }, -        syn::Body::Struct(syn::VariantData::Tuple(ref body)) => { -            let fields = (0..body.len()) -                .map(|_| quote! { __rng.gen() }) -                .collect::<Vec<_>>(); - -            quote! { #name (#(#fields),*) } -        }, -        syn::Body::Struct(syn::VariantData::Unit) => { -            quote! { #name } -        }, -        syn::Body::Enum(ref body) => { -            if body.is_empty() { -                panic!("`Rand` cannot be derived for enums with no variants"); -            } - -            let len = body.len(); -            let mut arms = body -                .iter() -                .map(|variant| { -                    let ident = &variant.ident; -                    match variant.data { -                        syn::VariantData::Struct(ref body) => { -                            let fields = body -                                .iter() -                                .filter_map(|field| field.ident.as_ref()) -                                .map(|ident| quote! { #ident: __rng.gen() }) -                                .collect::<Vec<_>>(); -                            quote! { #name::#ident { #(#fields,)* } } -                        }, -                        syn::VariantData::Tuple(ref body) => { -                            let fields = (0..body.len()) -                                .map(|_| quote! { __rng.gen() }) -                                .collect::<Vec<_>>(); - -                            quote! { #name::#ident (#(#fields),*) } -                        }, -                        syn::VariantData::Unit => quote! { #name::#ident } -                    } -                }); - -            match len { -                1 => quote! { #(#arms)* }, -                2 => { -                    let (a, b) = (arms.next(), arms.next()); -                    quote! { if __rng.gen() { #a } else { #b } } -                }, -                _ => { -                    let mut variants = arms -                        .enumerate() -                        .map(|(index, arm)| quote! { #index => #arm }) -                        .collect::<Vec<_>>(); -                    variants.push(quote! { _ => unreachable!() }); -                    quote! { match __rng.gen_range(0, #len) { #(#variants,)* } } -                }, -            } -        } -    }; - -    quote! { -        impl #impl_generics ::rand::Rand for #name #ty_generics #where_clause { -            #[inline] -            fn rand<__R: ::rand::Rng>(__rng: &mut __R) -> Self { -                #rand -            } -        } -    } -} | 
