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use proc_macro2::Span;
use syn::{
Meta, Result, Token, Type,
parse::{Parse, ParseStream},
spanned::Spanned,
};
#[derive(Debug)]
pub struct PrimitiveInput {
pub ty: Type,
pub manual_shrink_to_fit: Option<Span>,
}
impl Parse for PrimitiveInput {
fn parse(input: ParseStream) -> Result<Self> {
let ty: Type = input.parse()?;
let mut parsed_input = PrimitiveInput {
ty,
manual_shrink_to_fit: None,
};
if input.parse::<Option<Token![,]>>()?.is_some() {
let punctuated = input.parse_terminated(Meta::parse, Token![,])?;
for meta in punctuated {
match (
meta.path()
.get_ident()
.map(ToString::to_string)
.as_deref()
.unwrap_or_default(),
&meta,
) {
("manual_shrink_to_fit", Meta::Path(_)) => {
parsed_input.manual_shrink_to_fit = Some(meta.span())
}
(_, meta) => {
return Err(syn::Error::new_spanned(
meta,
"unexpected token, expected: \"manual_shrink_to_fit\"",
));
}
}
}
}
Ok(parsed_input)
}
}
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