David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 1 | //! Adapted from [`nom`](https://github.com/Geal/nom). |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 2 | |
| 3 | use unicode_xid::UnicodeXID; |
| 4 | |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 5 | use imp::LexError; |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 6 | |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 7 | pub type PResult<'a, O> = Result<(&'a str, O), LexError>; |
| 8 | |
| 9 | pub fn whitespace(input: &str) -> PResult<()> { |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 10 | if input.is_empty() { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 11 | return Err(LexError); |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 12 | } |
| 13 | |
| 14 | let bytes = input.as_bytes(); |
| 15 | let mut i = 0; |
| 16 | while i < bytes.len() { |
| 17 | let s = &input[i..]; |
| 18 | if bytes[i] == b'/' { |
| 19 | if s.starts_with("//") && (!s.starts_with("///") || s.starts_with("////")) && |
| 20 | !s.starts_with("//!") { |
| 21 | if let Some(len) = s.find('\n') { |
| 22 | i += len + 1; |
| 23 | continue; |
| 24 | } |
| 25 | break; |
| 26 | } else if s.starts_with("/*") && (!s.starts_with("/**") || s.starts_with("/***")) && |
| 27 | !s.starts_with("/*!") { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 28 | let (_, com) = block_comment(s)?; |
| 29 | i += com.len(); |
| 30 | continue; |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 31 | } |
| 32 | } |
| 33 | match bytes[i] { |
| 34 | b' ' | 0x09...0x0d => { |
| 35 | i += 1; |
| 36 | continue; |
| 37 | } |
| 38 | b if b <= 0x7f => {} |
| 39 | _ => { |
| 40 | let ch = s.chars().next().unwrap(); |
| 41 | if is_whitespace(ch) { |
| 42 | i += ch.len_utf8(); |
| 43 | continue; |
| 44 | } |
| 45 | } |
| 46 | } |
| 47 | return if i > 0 { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 48 | Ok((s, ())) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 49 | } else { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 50 | Err(LexError) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 51 | }; |
| 52 | } |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 53 | Ok(("", ())) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 54 | } |
| 55 | |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 56 | pub fn block_comment(input: &str) -> PResult<&str> { |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 57 | if !input.starts_with("/*") { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 58 | return Err(LexError); |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 59 | } |
| 60 | |
| 61 | let mut depth = 0; |
| 62 | let bytes = input.as_bytes(); |
| 63 | let mut i = 0; |
| 64 | let upper = bytes.len() - 1; |
| 65 | while i < upper { |
| 66 | if bytes[i] == b'/' && bytes[i + 1] == b'*' { |
| 67 | depth += 1; |
| 68 | i += 1; // eat '*' |
| 69 | } else if bytes[i] == b'*' && bytes[i + 1] == b'/' { |
| 70 | depth -= 1; |
| 71 | if depth == 0 { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 72 | return Ok((&input[i + 2..], &input[..i + 2])); |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 73 | } |
| 74 | i += 1; // eat '/' |
| 75 | } |
| 76 | i += 1; |
| 77 | } |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 78 | Err(LexError) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 79 | } |
| 80 | |
| 81 | pub fn skip_whitespace(input: &str) -> &str { |
| 82 | match whitespace(input) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 83 | Ok((rest, _)) => rest, |
| 84 | Err(LexError) => input, |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 85 | } |
| 86 | } |
| 87 | |
| 88 | fn is_whitespace(ch: char) -> bool { |
| 89 | // Rust treats left-to-right mark and right-to-left mark as whitespace |
| 90 | ch.is_whitespace() || ch == '\u{200e}' || ch == '\u{200f}' |
| 91 | } |
| 92 | |
David Tolnay | 744a6b8 | 2017-06-01 11:34:29 -0700 | [diff] [blame^] | 93 | pub fn word_break(input: &str) -> PResult<()> { |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 94 | match input.chars().next() { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 95 | Some(ch) if UnicodeXID::is_xid_continue(ch) => Err(LexError), |
| 96 | Some(_) | None => Ok((input, ())), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 97 | } |
| 98 | } |
| 99 | |
| 100 | macro_rules! named { |
| 101 | ($name:ident -> $o:ty, $submac:ident!( $($args:tt)* )) => { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 102 | fn $name(i: &str) -> $crate::strnom::PResult<$o> { |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 103 | $submac!(i, $($args)*) |
| 104 | } |
| 105 | }; |
| 106 | } |
| 107 | |
| 108 | macro_rules! alt { |
| 109 | ($i:expr, $e:ident | $($rest:tt)*) => { |
| 110 | alt!($i, call!($e) | $($rest)*) |
| 111 | }; |
| 112 | |
| 113 | ($i:expr, $subrule:ident!( $($args:tt)*) | $($rest:tt)*) => { |
| 114 | match $subrule!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 115 | res @ Ok(_) => res, |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 116 | _ => alt!($i, $($rest)*) |
| 117 | } |
| 118 | }; |
| 119 | |
| 120 | ($i:expr, $subrule:ident!( $($args:tt)* ) => { $gen:expr } | $($rest:tt)+) => { |
| 121 | match $subrule!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 122 | Ok((i, o)) => Ok((i, $gen(o))), |
| 123 | Err(LexError) => alt!($i, $($rest)*) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 124 | } |
| 125 | }; |
| 126 | |
| 127 | ($i:expr, $e:ident => { $gen:expr } | $($rest:tt)*) => { |
| 128 | alt!($i, call!($e) => { $gen } | $($rest)*) |
| 129 | }; |
| 130 | |
| 131 | ($i:expr, $e:ident => { $gen:expr }) => { |
| 132 | alt!($i, call!($e) => { $gen }) |
| 133 | }; |
| 134 | |
| 135 | ($i:expr, $subrule:ident!( $($args:tt)* ) => { $gen:expr }) => { |
| 136 | match $subrule!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 137 | Ok((i, o)) => Ok((i, $gen(o))), |
| 138 | Err(LexError) => Err(LexError), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 139 | } |
| 140 | }; |
| 141 | |
| 142 | ($i:expr, $e:ident) => { |
| 143 | alt!($i, call!($e)) |
| 144 | }; |
| 145 | |
| 146 | ($i:expr, $subrule:ident!( $($args:tt)*)) => { |
| 147 | $subrule!($i, $($args)*) |
| 148 | }; |
| 149 | } |
| 150 | |
| 151 | macro_rules! do_parse { |
| 152 | ($i:expr, ( $($rest:expr),* )) => { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 153 | Ok(($i, ( $($rest),* ))) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 154 | }; |
| 155 | |
| 156 | ($i:expr, $e:ident >> $($rest:tt)*) => { |
| 157 | do_parse!($i, call!($e) >> $($rest)*) |
| 158 | }; |
| 159 | |
| 160 | ($i:expr, $submac:ident!( $($args:tt)* ) >> $($rest:tt)*) => { |
| 161 | match $submac!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 162 | Err(LexError) => Err(LexError), |
| 163 | Ok((i, _)) => do_parse!(i, $($rest)*), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 164 | } |
| 165 | }; |
| 166 | |
| 167 | ($i:expr, $field:ident : $e:ident >> $($rest:tt)*) => { |
| 168 | do_parse!($i, $field: call!($e) >> $($rest)*) |
| 169 | }; |
| 170 | |
| 171 | ($i:expr, $field:ident : $submac:ident!( $($args:tt)* ) >> $($rest:tt)*) => { |
| 172 | match $submac!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 173 | Err(LexError) => Err(LexError), |
| 174 | Ok((i, o)) => { |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 175 | let $field = o; |
| 176 | do_parse!(i, $($rest)*) |
| 177 | }, |
| 178 | } |
| 179 | }; |
| 180 | } |
| 181 | |
| 182 | macro_rules! peek { |
| 183 | ($i:expr, $submac:ident!( $($args:tt)* )) => { |
| 184 | match $submac!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 185 | Ok((_, o)) => Ok(($i, o)), |
| 186 | Err(LexError) => Err(LexError), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 187 | } |
| 188 | }; |
| 189 | } |
| 190 | |
| 191 | macro_rules! call { |
| 192 | ($i:expr, $fun:expr $(, $args:expr)*) => { |
| 193 | $fun($i $(, $args)*) |
| 194 | }; |
| 195 | } |
| 196 | |
| 197 | macro_rules! option { |
| 198 | ($i:expr, $f:expr) => { |
| 199 | match $f($i) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 200 | Ok((i, o)) => Ok((i, Some(o))), |
| 201 | Err(LexError) => Ok(($i, None)), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 202 | } |
| 203 | }; |
| 204 | } |
| 205 | |
| 206 | macro_rules! take_until { |
| 207 | ($i:expr, $substr:expr) => {{ |
| 208 | if $substr.len() > $i.len() { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 209 | Err(LexError) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 210 | } else { |
| 211 | let substr_vec: Vec<char> = $substr.chars().collect(); |
| 212 | let mut window: Vec<char> = vec![]; |
| 213 | let mut offset = $i.len(); |
| 214 | let mut parsed = false; |
| 215 | for (o, c) in $i.char_indices() { |
| 216 | window.push(c); |
| 217 | if window.len() > substr_vec.len() { |
| 218 | window.remove(0); |
| 219 | } |
| 220 | if window == substr_vec { |
| 221 | parsed = true; |
| 222 | window.pop(); |
| 223 | let window_len: usize = window.iter() |
| 224 | .map(|x| x.len_utf8()) |
| 225 | .fold(0, |x, y| x + y); |
| 226 | offset = o - window_len; |
| 227 | break; |
| 228 | } |
| 229 | } |
| 230 | if parsed { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 231 | Ok((&$i[offset..], &$i[..offset])) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 232 | } else { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 233 | Err(LexError) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 234 | } |
| 235 | } |
| 236 | }}; |
| 237 | } |
| 238 | |
| 239 | macro_rules! tuple { |
| 240 | ($i:expr, $($rest:tt)*) => { |
| 241 | tuple_parser!($i, (), $($rest)*) |
| 242 | }; |
| 243 | } |
| 244 | |
| 245 | /// Do not use directly. Use `tuple!`. |
| 246 | macro_rules! tuple_parser { |
| 247 | ($i:expr, ($($parsed:tt),*), $e:ident, $($rest:tt)*) => { |
| 248 | tuple_parser!($i, ($($parsed),*), call!($e), $($rest)*) |
| 249 | }; |
| 250 | |
| 251 | ($i:expr, (), $submac:ident!( $($args:tt)* ), $($rest:tt)*) => { |
| 252 | match $submac!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 253 | Err(LexError) => Err(LexError), |
| 254 | Ok((i, o)) => tuple_parser!(i, (o), $($rest)*), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 255 | } |
| 256 | }; |
| 257 | |
| 258 | ($i:expr, ($($parsed:tt)*), $submac:ident!( $($args:tt)* ), $($rest:tt)*) => { |
| 259 | match $submac!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 260 | Err(LexError) => Err(LexError), |
| 261 | Ok((i, o)) => tuple_parser!(i, ($($parsed)* , o), $($rest)*), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 262 | } |
| 263 | }; |
| 264 | |
| 265 | ($i:expr, ($($parsed:tt),*), $e:ident) => { |
| 266 | tuple_parser!($i, ($($parsed),*), call!($e)) |
| 267 | }; |
| 268 | |
| 269 | ($i:expr, (), $submac:ident!( $($args:tt)* )) => { |
| 270 | $submac!($i, $($args)*) |
| 271 | }; |
| 272 | |
| 273 | ($i:expr, ($($parsed:expr),*), $submac:ident!( $($args:tt)* )) => { |
| 274 | match $submac!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 275 | Err(LexError) => Err(LexError), |
| 276 | Ok((i, o)) => Ok((i, ($($parsed),*, o))) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 277 | } |
| 278 | }; |
| 279 | |
| 280 | ($i:expr, ($($parsed:expr),*)) => { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 281 | Ok(($i, ($($parsed),*))) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 282 | }; |
| 283 | } |
| 284 | |
| 285 | macro_rules! not { |
| 286 | ($i:expr, $submac:ident!( $($args:tt)* )) => { |
| 287 | match $submac!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 288 | Ok((_, _)) => Err(LexError), |
| 289 | Err(LexError) => Ok(($i, ())), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 290 | } |
| 291 | }; |
| 292 | } |
| 293 | |
| 294 | macro_rules! tag { |
| 295 | ($i:expr, $tag:expr) => { |
| 296 | if $i.starts_with($tag) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 297 | Ok((&$i[$tag.len()..], &$i[..$tag.len()])) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 298 | } else { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 299 | Err(LexError) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 300 | } |
| 301 | }; |
| 302 | } |
| 303 | |
| 304 | macro_rules! punct { |
| 305 | ($i:expr, $punct:expr) => { |
| 306 | $crate::strnom::punct($i, $punct) |
| 307 | }; |
| 308 | } |
| 309 | |
| 310 | /// Do not use directly. Use `punct!`. |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 311 | pub fn punct<'a>(input: &'a str, token: &'static str) -> PResult<'a, &'a str> { |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 312 | let input = skip_whitespace(input); |
| 313 | if input.starts_with(token) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 314 | Ok((&input[token.len()..], token)) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 315 | } else { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 316 | Err(LexError) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 317 | } |
| 318 | } |
| 319 | |
| 320 | macro_rules! keyword { |
| 321 | ($i:expr, $keyword:expr) => { |
| 322 | $crate::strnom::keyword($i, $keyword) |
| 323 | }; |
| 324 | } |
| 325 | |
| 326 | /// Do not use directly. Use `keyword!`. |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 327 | pub fn keyword<'a>(input: &'a str, token: &'static str) -> PResult<'a, &'a str> { |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 328 | match punct(input, token) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 329 | Ok((rest, _)) => { |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 330 | match word_break(rest) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 331 | Ok((_, _)) => Ok((rest, token)), |
| 332 | Err(LexError) => Err(LexError), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 333 | } |
| 334 | } |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 335 | Err(LexError) => Err(LexError), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 336 | } |
| 337 | } |
| 338 | |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 339 | macro_rules! preceded { |
| 340 | ($i:expr, $submac:ident!( $($args:tt)* ), $submac2:ident!( $($args2:tt)* )) => { |
| 341 | match tuple!($i, $submac!($($args)*), $submac2!($($args2)*)) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 342 | Ok((remaining, (_, o))) => Ok((remaining, o)), |
| 343 | Err(LexError) => Err(LexError), |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 344 | } |
| 345 | }; |
| 346 | |
| 347 | ($i:expr, $submac:ident!( $($args:tt)* ), $g:expr) => { |
| 348 | preceded!($i, $submac!($($args)*), call!($g)) |
| 349 | }; |
| 350 | } |
| 351 | |
| 352 | macro_rules! delimited { |
| 353 | ($i:expr, $submac:ident!( $($args:tt)* ), $($rest:tt)+) => { |
| 354 | match tuple_parser!($i, (), $submac!($($args)*), $($rest)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 355 | Err(LexError) => Err(LexError), |
| 356 | Ok((i1, (_, o, _))) => Ok((i1, o)) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 357 | } |
| 358 | }; |
| 359 | } |
| 360 | |
| 361 | macro_rules! map { |
| 362 | ($i:expr, $submac:ident!( $($args:tt)* ), $g:expr) => { |
| 363 | match $submac!($i, $($args)*) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 364 | Err(LexError) => Err(LexError), |
| 365 | Ok((i, o)) => Ok((i, call!(o, $g))) |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 366 | } |
| 367 | }; |
| 368 | |
| 369 | ($i:expr, $f:expr, $g:expr) => { |
| 370 | map!($i, call!($f), $g) |
| 371 | }; |
| 372 | } |
| 373 | |
| 374 | macro_rules! many0 { |
| 375 | ($i:expr, $f:expr) => {{ |
| 376 | let ret; |
| 377 | let mut res = ::std::vec::Vec::new(); |
| 378 | let mut input = $i; |
| 379 | |
| 380 | loop { |
| 381 | if input.is_empty() { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 382 | ret = Ok((input, res)); |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 383 | break; |
| 384 | } |
| 385 | |
| 386 | match $f(input) { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 387 | Err(LexError) => { |
| 388 | ret = Ok((input, res)); |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 389 | break; |
| 390 | } |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 391 | Ok((i, o)) => { |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 392 | // loop trip must always consume (otherwise infinite loops) |
| 393 | if i.len() == input.len() { |
David Tolnay | 1218e12 | 2017-06-01 11:13:45 -0700 | [diff] [blame] | 394 | ret = Err(LexError); |
David Tolnay | b103266 | 2017-05-31 15:52:28 -0700 | [diff] [blame] | 395 | break; |
| 396 | } |
| 397 | |
| 398 | res.push(o); |
| 399 | input = i; |
| 400 | } |
| 401 | } |
| 402 | } |
| 403 | |
| 404 | ret |
| 405 | }}; |
| 406 | } |