QuoteOption, possibly updated for nightly

QuoteOption.rs

use quote::{Tokens, ToTokens};
use proc_macro2::{Term, Span, Group, Delimiter, TokenStream};

pub struct QuoteOption<T>(pub Option<T>);

impl<T> ToTokens for QuoteOption<T>
  where T: ToTokens
{
  fn to_tokens(&self, tokens: &mut Tokens) {
    // tokens.append(Term::new("{", Span::call_site()));
    // tokens.append(Term::new("::", Span::call_site()));
    // tokens.append(Term::new("std", Span::call_site()));
    // tokens.append(Term::new("::", Span::call_site()));
    // tokens.append(Term::new("option", Span::call_site()));
    // tokens.append(Term::new("::", Span::call_site()));
    // tokens.append(Term::new("Option", Span::call_site()));
    // tokens.append(Term::new("::", Span::call_site()));
    match self.0 {
      Some(ref t) => {
        tokens.append(Term::new("Some", Span::call_site()));
        let mut inner_tokens = Tokens::new();
        t.to_tokens(&mut inner_tokens);
        tokens.append(Group::new(Delimiter::Parenthesis, inner_tokens.into()));
      }
      None => {
        tokens.append(Term::new("None", Span::call_site()));
      }
    }
    // tokens.append(Term::new("}", Span::call_site()));
  }
}