use syn::parse::Parse;
use syn::parse::ParseStream;
use syn::Error;
use syn::Ident;
use syn::Result;
use syn::Token;
#[derive(Clone, Debug, Default)]
pub struct Attributes {
pub is_unstable: bool,
pub is_v8: bool,
pub must_be_fast: bool,
pub deferred: bool,
pub is_wasm: bool,
pub relation: Option<Ident>,
}
impl Parse for Attributes {
fn parse(input: ParseStream) -> Result<Self> {
let mut self_ = Self::default();
let mut fast = false;
while let Ok(v) = input.parse::<Ident>() {
match v.to_string().as_str() {
"unstable" => self_.is_unstable = true,
"v8" => self_.is_v8 = true,
"fast" => fast = true,
"deferred" => self_.deferred = true,
"wasm" => self_.is_wasm = true,
"slow" => {
if !fast {
return Err(Error::new(
input.span(),
"relational attributes can only be used with fast attribute",
));
}
input.parse::<Token![=]>()?;
self_.relation = Some(input.parse()?);
}
_ => {
return Err(Error::new(
input.span(),
"invalid attribute, expected one of: unstable, v8, fast, deferred, wasm",
));
}
};
let _ = input.parse::<Token![,]>();
}
self_.must_be_fast = self_.is_wasm || fast;
Ok(self_)
}
}