Macro syn::parenthesized

macro_rules! parenthesized {
    ($content:ident in $cursor:expr) => { ... };
}

Parse a set of parentheses and expose their content to subsequent parsers.

Example

# use quote::quote;
#
use syn::{parenthesized, token, Ident, Result, Token, Type};
use syn::parse::{Parse, ParseStream};
use syn::punctuated::Punctuated;

// Parse a simplified tuple struct syntax like:
//
//     struct S(A, B);
struct TupleStruct {
    struct_token: Token![struct],
    ident: Ident,
    paren_token: token::Paren,
    fields: Punctuated<Type, Token![,]>,
    semi_token: Token![;],
}

impl Parse for TupleStruct {
    fn parse(input: ParseStream) -> Result<Self> {
        let content;
        Ok(TupleStruct {
            struct_token: input.parse()?,
            ident: input.parse()?,
            paren_token: parenthesized!(content in input),
            fields: content.parse_terminated(Type::parse)?,
            semi_token: input.parse()?,
        })
    }
}
#
# fn main() {
#     let input = quote! {
#         struct S(A, B);
#     };
#     syn::parse2::<TupleStruct>(input).unwrap();
# }