1 // Copyright 2015 The Servo Project Developers. See the
2 // COPYRIGHT file at the top-level directory of this distribution.
3 //
4 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
5 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
7 // option. This file may not be copied, modified, or distributed
8 // except according to those terms.
9 
10 use crate::BidiClass;
11 
12 /// This is the return value of [`BidiDataSource::bidi_matched_opening_bracket()`].
13 ///
14 /// It represents the matching *normalized* opening bracket for a given bracket in a bracket pair,
15 /// and whether or not that bracket is opening.
16 #[derive(Debug, Copy, Clone)]
17 pub struct BidiMatchedOpeningBracket {
18     /// The corresponding opening bracket in this bracket pair, normalized
19     ///
20     /// In case of opening brackets, this will be the bracket itself, except for when the bracket
21     /// is not normalized, in which case it will be the normalized form.
22     pub opening: char,
23     /// Whether or not the requested bracket was an opening bracket. True for opening
24     pub is_open: bool,
25 }
26 
27 /// This trait abstracts over a data source that is able to produce the Unicode Bidi class for a given
28 /// character
29 pub trait BidiDataSource {
bidi_class(&self, c: char) -> BidiClass30     fn bidi_class(&self, c: char) -> BidiClass;
31     /// If this character is a bracket according to BidiBrackets.txt,
32     /// return the corresponding *normalized* *opening bracket* of the pair,
33     /// and whether or not it itself is an opening bracket.
34     ///
35     /// This effectively buckets brackets into equivalence classes keyed on the
36     /// normalized opening bracket.
37     ///
38     /// The default implementation will pull in a small amount of hardcoded data,
39     /// regardless of the `hardcoded-data` feature. This is in part for convenience
40     /// (since this data is small and changes less often), and in part so that this method can be
41     /// added without needing a breaking version bump.
42     /// Override this method in your custom data source to prevent the use of hardcoded data.
bidi_matched_opening_bracket(&self, c: char) -> Option<BidiMatchedOpeningBracket>43     fn bidi_matched_opening_bracket(&self, c: char) -> Option<BidiMatchedOpeningBracket> {
44         crate::char_data::bidi_matched_opening_bracket(c)
45     }
46 }
47