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use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};
use proc_macro2::{Ident, Span, TokenStream, TokenTree};
use quote::quote;
use syn::parse::{Parse, ParseStream, Result};
use syn::{braced, parenthesized, parse_macro_input, Token};
pub fn wrap(output: TokenStream) -> TokenStream {
let mut hasher = DefaultHasher::default();
output.to_string().hash(&mut hasher);
let mangled_name = format!("_paste_{}", hasher.finish());
let ident = Ident::new(&mangled_name, Span::call_site());
quote! {
#[derive(paste::EnumHack)]
enum #ident {
Value = (stringify! {
#output
}, 0).1,
}
}
}
struct EnumHack {
token_stream: TokenStream,
}
impl Parse for EnumHack {
fn parse(input: ParseStream) -> Result<Self> {
input.parse::<Token![enum]>()?;
input.parse::<Ident>()?;
let braces;
braced!(braces in input);
braces.parse::<Ident>()?;
braces.parse::<Token![=]>()?;
let parens;
parenthesized!(parens in braces);
parens.parse::<Ident>()?;
parens.parse::<Token![!]>()?;
let inner;
braced!(inner in parens);
let token_stream: TokenStream = inner.parse()?;
parens.parse::<Token![,]>()?;
parens.parse::<TokenTree>()?;
braces.parse::<Token![.]>()?;
braces.parse::<TokenTree>()?;
braces.parse::<Token![,]>()?;
Ok(EnumHack { token_stream })
}
}
pub fn extract(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let inner = parse_macro_input!(input as EnumHack);
proc_macro::TokenStream::from(inner.token_stream)
}
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