1 // SPDX-License-Identifier: GPL-2.0 2 3 use proc_macro::{token_stream, Group, TokenTree}; 4 5 pub(crate) fn try_ident(it: &mut token_stream::IntoIter) -> Option<String> { 6 if let Some(TokenTree::Ident(ident)) = it.next() { 7 Some(ident.to_string()) 8 } else { 9 None 10 } 11 } 12 13 pub(crate) fn try_literal(it: &mut token_stream::IntoIter) -> Option<String> { 14 if let Some(TokenTree::Literal(literal)) = it.next() { 15 Some(literal.to_string()) 16 } else { 17 None 18 } 19 } 20 21 pub(crate) fn try_string(it: &mut token_stream::IntoIter) -> Option<String> { 22 try_literal(it).and_then(|string| { 23 if string.starts_with('\"') && string.ends_with('\"') { 24 let content = &string[1..string.len() - 1]; 25 if content.contains('\\') { 26 panic!("Escape sequences in string literals not yet handled"); 27 } 28 Some(content.to_string()) 29 } else if string.starts_with("r\"") { 30 panic!("Raw string literals are not yet handled"); 31 } else { 32 None 33 } 34 }) 35 } 36 37 pub(crate) fn expect_ident(it: &mut token_stream::IntoIter) -> String { 38 try_ident(it).expect("Expected Ident") 39 } 40 41 pub(crate) fn expect_punct(it: &mut token_stream::IntoIter) -> char { 42 if let TokenTree::Punct(punct) = it.next().expect("Reached end of token stream for Punct") { 43 punct.as_char() 44 } else { 45 panic!("Expected Punct"); 46 } 47 } 48 49 pub(crate) fn expect_string(it: &mut token_stream::IntoIter) -> String { 50 try_string(it).expect("Expected string") 51 } 52 53 pub(crate) fn expect_string_ascii(it: &mut token_stream::IntoIter) -> String { 54 let string = try_string(it).expect("Expected string"); 55 assert!(string.is_ascii(), "Expected ASCII string"); 56 string 57 } 58 59 pub(crate) fn expect_group(it: &mut token_stream::IntoIter) -> Group { 60 if let TokenTree::Group(group) = it.next().expect("Reached end of token stream for Group") { 61 group 62 } else { 63 panic!("Expected Group"); 64 } 65 } 66 67 pub(crate) fn expect_end(it: &mut token_stream::IntoIter) { 68 if it.next().is_some() { 69 panic!("Expected end"); 70 } 71 } 72