aboutsummaryrefslogtreecommitdiff
path: root/src/parser/event_parser/grammar/mod.rs
blob: 82f8b7f3e77cc62b08b4ba151524d9cd9cbfa6b3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
use super::parser::{Parser, TokenSet};
use SyntaxKind;
use syntax_kinds::*;

mod items;
mod attributes;
mod expressions;
mod types;
mod paths;

pub(crate) fn file(p: &mut Parser) {
    let file = p.start();
    p.eat(SHEBANG);
    items::mod_contents(p);
    file.complete(p, FILE);
}

fn visibility(p: &mut Parser) {
    if p.at(PUB_KW) {
        let vis = p.start();
        p.bump();
        if p.at(L_PAREN) {
            match p.raw_lookahead(1) {
                CRATE_KW | SELF_KW | SUPER_KW | IN_KW => {
                    p.bump();
                    if p.bump() == IN_KW {
                        paths::use_path(p);
                    }
                    p.expect(R_PAREN);
                }
                _ => (),
            }
        }
        vis.complete(p, VISIBILITY);
    }
}

fn alias(p: &mut Parser) -> bool {
    if p.at(AS_KW) {
        let alias = p.start();
        p.bump();
        p.expect(IDENT);
        alias.complete(p, ALIAS);
    }
    true //FIXME: return false if three are errors
}

impl<'p> Parser<'p> {
    fn at<L: Lookahead>(&self, l: L) -> bool {
        l.is_ahead(self)
    }

    fn err_and_bump(&mut self, message: &str) {
        let err = self.start();
        self.error().message(message).emit();
        self.bump();
        err.complete(self, ERROR);
    }

    pub(crate) fn expect(&mut self, kind: SyntaxKind) -> bool {
        if self.at(kind) {
            self.bump();
            true
        } else {
            self.error().message(format!("expected {:?}", kind)).emit();
            false
        }
    }

    fn eat(&mut self, kind: SyntaxKind) -> bool {
        self.current() == kind && {
            self.bump();
            true
        }
    }
}

trait Lookahead: Copy {
    fn is_ahead(self, p: &Parser) -> bool;
    fn consume(p: &mut Parser);
}

impl Lookahead for SyntaxKind {
    fn is_ahead(self, p: &Parser) -> bool {
        p.current() == self
    }

    fn consume(p: &mut Parser) {
        p.bump();
    }
}

impl Lookahead for [SyntaxKind; 2] {
    fn is_ahead(self, p: &Parser) -> bool {
        p.current() == self[0] && p.raw_lookahead(1) == self[1]
    }

    fn consume(p: &mut Parser) {
        p.bump();
        p.bump();
    }
}

impl Lookahead for [SyntaxKind; 3] {
    fn is_ahead(self, p: &Parser) -> bool {
        p.current() == self[0] && p.raw_lookahead(1) == self[1] && p.raw_lookahead(2) == self[2]
    }

    fn consume(p: &mut Parser) {
        p.bump();
        p.bump();
        p.bump();
    }
}

#[derive(Clone, Copy)]
struct AnyOf<'a>(&'a [SyntaxKind]);

impl<'a> Lookahead for AnyOf<'a> {
    fn is_ahead(self, p: &Parser) -> bool {
        let curr = p.current();
        self.0.iter().any(|&k| k == curr)
    }

    fn consume(p: &mut Parser) {
        p.bump();
    }
}