1 // pest. The Elegant Parser 2 // Copyright (c) 2018 Dragoș Tiselice 3 // 4 // Licensed under the Apache License, Version 2.0 5 // <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT 6 // license <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your 7 // option. All files in the project carrying such notice may not be copied, 8 // modified, or distributed except according to those terms. 9 10 // This structure serves to improve performance over Token objects in two ways: 11 // 12 // * it is smaller than a Token, leading to both less memory use when stored in the queue but also 13 // increased speed when pushing to the queue 14 // * it finds its pair in O(1) time instead of O(N), since pair positions are known at parse time 15 // and can easily be stored instead of recomputed 16 #[derive(Debug)] 17 pub enum QueueableToken<'i, R> { 18 Start { 19 /// Queue (as a vec) contains both `Start` token and `End` for the same rule. 20 /// This field is an index of corresponding `End` token in vec. 21 end_token_index: usize, 22 /// Position from which rule was tried to parse (or successfully parsed). 23 input_pos: usize, 24 }, 25 End { 26 /// Queue (as a vec) contains both `Start` token and `End` for the same rule. 27 /// This filed is an index of corresponding `Start` token in vec. 28 start_token_index: usize, 29 rule: R, 30 tag: Option<&'i str>, 31 /// Position at which successfully parsed rule finished (ended). 32 input_pos: usize, 33 }, 34 } 35