tests/test_grouping.rs

extern crate proc_macro2;
extern crate syn;

mod features;

#[macro_use]
mod macros;

use proc_macro2::{Delimiter, Group, Literal, Punct, Spacing, TokenStream, TokenTree};
use syn::Expr;

use std::iter::FromIterator;

#[test]
fn test_grouping() {
    let tokens: TokenStream = TokenStream::from_iter(vec![
        TokenTree::Literal(Literal::i32_suffixed(1)),
        TokenTree::Punct(Punct::new('+', Spacing::Alone)),
        TokenTree::Group(Group::new(
            Delimiter::None,
            TokenStream::from_iter(vec![
                TokenTree::Literal(Literal::i32_suffixed(2)),
                TokenTree::Punct(Punct::new('+', Spacing::Alone)),
                TokenTree::Literal(Literal::i32_suffixed(3)),
            ]),
        )),
        TokenTree::Punct(Punct::new('*', Spacing::Alone)),
        TokenTree::Literal(Literal::i32_suffixed(4)),
    ]);

    assert_eq!(tokens.to_string(), "1i32 +  2i32 + 3i32  * 4i32");

    snapshot!(tokens as Expr, @r###"
   ⋮Expr::Binary {
   ⋮    left: Expr::Lit {
   ⋮        lit: 1,
   ⋮    },
   ⋮    op: Add,
   ⋮    right: Expr::Binary {
   ⋮        left: Expr::Group {
   ⋮            expr: Expr::Binary {
   ⋮                left: Expr::Lit {
   ⋮                    lit: 2,
   ⋮                },
   ⋮                op: Add,
   ⋮                right: Expr::Lit {
   ⋮                    lit: 3,
   ⋮                },
   ⋮            },
   ⋮        },
   ⋮        op: Mul,
   ⋮        right: Expr::Lit {
   ⋮            lit: 4,
   ⋮        },
   ⋮    },
   ⋮}
    "###);
}