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 - } - } - } -} |