aboutsummaryrefslogtreecommitdiff
path: root/crates/ra_syntax/src/parsing/grammar/params.rs
blob: 185386569aa01014c70627823de2fa9cddfb965e (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
129
130
131
132
133
134
135
136
137
138
139
use super::*;

// test param_list
// fn a() {}
// fn b(x: i32) {}
// fn c(x: i32, ) {}
// fn d(x: i32, y: ()) {}
pub(super) fn param_list(p: &mut Parser) {
    list_(p, Flavor::Normal)
}

// test param_list_opt_patterns
// fn foo<F: FnMut(&mut Foo<'a>)>(){}
pub(super) fn param_list_opt_patterns(p: &mut Parser) {
    list_(p, Flavor::OptionalPattern)
}

pub(super) fn param_list_opt_types(p: &mut Parser) {
    list_(p, Flavor::OptionalType)
}

#[derive(Clone, Copy, Eq, PartialEq)]
enum Flavor {
    OptionalType,
    OptionalPattern,
    Normal,
}

impl Flavor {
    fn type_required(self) -> bool {
        match self {
            Flavor::OptionalType => false,
            _ => true,
        }
    }
}

fn list_(p: &mut Parser, flavor: Flavor) {
    let (bra, ket) = if flavor.type_required() { (L_PAREN, R_PAREN) } else { (PIPE, PIPE) };
    assert!(p.at(bra));
    let m = p.start();
    p.bump();
    if flavor.type_required() {
        opt_self_param(p);
    }
    while !p.at(EOF) && !p.at(ket) {
        if !p.at_ts(VALUE_PARAMETER_FIRST) {
            p.error("expected value parameter");
            break;
        }
        value_parameter(p, flavor);
        if !p.at(ket) {
            p.expect(COMMA);
        }
    }
    p.expect(ket);
    m.complete(p, PARAM_LIST);
}

const VALUE_PARAMETER_FIRST: TokenSet = patterns::PATTERN_FIRST.union(types::TYPE_FIRST);

fn value_parameter(p: &mut Parser, flavor: Flavor) {
    let m = p.start();
    match flavor {
        Flavor::OptionalType | Flavor::Normal => {
            patterns::pattern(p);
            if p.at(COLON) || flavor.type_required() {
                types::ascription(p)
            }
        }
        // test value_parameters_no_patterns
        // type F = Box<Fn(a: i32, &b: &i32, &mut c: &i32, ())>;
        Flavor::OptionalPattern => {
            let la0 = p.current();
            let la1 = p.nth(1);
            let la2 = p.nth(2);
            let la3 = p.nth(3);

            // test trait_fn_placeholder_parameter
            // trait Foo {
            //     fn bar(_: u64);
            // }
            if (la0 == IDENT || la0 == UNDERSCORE) && la1 == COLON
                || la0 == AMP && la1 == IDENT && la2 == COLON
                || la0 == AMP && la1 == MUT_KW && la2 == IDENT && la3 == COLON
            {
                patterns::pattern(p);
                types::ascription(p);
            } else {
                types::type_(p);
            }
        }
    }
    m.complete(p, PARAM);
}

// test self_param
// impl S {
//     fn a(self) {}
//     fn b(&self,) {}
//     fn c(&'a self,) {}
//     fn d(&'a mut self, x: i32) {}
//     fn e(mut self) {}
// }
fn opt_self_param(p: &mut Parser) {
    let m;
    if p.at(SELF_KW) || p.at(MUT_KW) && p.nth(1) == SELF_KW {
        m = p.start();
        p.eat(MUT_KW);
        p.eat(SELF_KW);
        // test arb_self_types
        // impl S {
        //     fn a(self: &Self) {}
        //     fn b(mut self: Box<Self>) {}
        // }
        if p.at(COLON) {
            types::ascription(p);
        }
    } else {
        let la1 = p.nth(1);
        let la2 = p.nth(2);
        let la3 = p.nth(3);
        let n_toks = match (p.current(), la1, la2, la3) {
            (AMP, SELF_KW, _, _) => 2,
            (AMP, MUT_KW, SELF_KW, _) => 3,
            (AMP, LIFETIME, SELF_KW, _) => 3,
            (AMP, LIFETIME, MUT_KW, SELF_KW) => 4,
            _ => return,
        };
        m = p.start();
        for _ in 0..n_toks {
            p.bump();
        }
    }
    m.complete(p, SELF_PARAM);
    if !p.at(R_PAREN) {
        p.expect(COMMA);
    }
}