aboutsummaryrefslogtreecommitdiff
path: root/crates/ra_parser/src/grammar.rs
blob: 7dfac2813e2c812b37d8062279e10ea7829d1e99 (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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
//! This is the actual "grammar" of the Rust language.
//!
//! Each function in this module and its children corresponds
//! to a production of the formal grammar. Submodules roughly
//! correspond to different *areas* of the grammar. By convention,
//! each submodule starts with `use super::*` import and exports
//! "public" productions via `pub(super)`.
//!
//! See docs for `Parser` to learn about API, available to the grammar,
//! and see docs for `Event` to learn how this actually manages to
//! produce parse trees.
//!
//! Code in this module also contains inline tests, which start with
//! `// test name-of-the-test` comment and look like this:
//!
//! ```
//! // test function_with_zero_parameters
//! // fn foo() {}
//! ```
//!
//! After adding a new inline-test, run `cargo xtask codegen` to
//! extract it as a standalone text-fixture into
//! `crates/ra_syntax/test_data/parser/`, and run `cargo test` once to
//! create the "gold" value.
//!
//! Coding convention: rules like `where_clause` always produce either a
//! node or an error, rules like `opt_where_clause` may produce nothing.
//! Non-opt rules typically start with `assert!(p.at(FIRST_TOKEN))`, the
//! caller is responsible for branching on the first token.
mod attributes;
mod expressions;
mod items;
mod params;
mod paths;
mod patterns;
mod type_args;
mod type_params;
mod types;

use crate::{
    parser::{CompletedMarker, Marker, Parser},
    SyntaxKind::{self, *},
    TokenSet,
};

pub(crate) fn root(p: &mut Parser) {
    let m = p.start();
    p.eat(SHEBANG);
    items::mod_contents(p, false);
    m.complete(p, SOURCE_FILE);
}

/// Various pieces of syntax that can be parsed by macros by example
pub(crate) mod fragments {
    use super::*;

    pub(crate) use super::{
        expressions::block_expr, paths::type_path as path, patterns::pattern, types::type_,
    };

    pub(crate) fn expr(p: &mut Parser) {
        let _ = expressions::expr(p);
    }

    pub(crate) fn stmt(p: &mut Parser) {
        expressions::stmt(p, expressions::StmtWithSemi::No)
    }

    pub(crate) fn opt_visibility(p: &mut Parser) {
        let _ = super::opt_visibility(p);
    }

    // Parse a meta item , which excluded [], e.g : #[ MetaItem ]
    pub(crate) fn meta_item(p: &mut Parser) {
        fn is_delimiter(p: &mut Parser) -> bool {
            matches!(p.current(), T!['{'] | T!['('] | T!['['])
        }

        if is_delimiter(p) {
            items::token_tree(p);
            return;
        }

        let m = p.start();
        while !p.at(EOF) {
            if is_delimiter(p) {
                items::token_tree(p);
                break;
            } else {
                // https://doc.rust-lang.org/reference/attributes.html
                // https://doc.rust-lang.org/reference/paths.html#simple-paths
                // The start of an meta must be a simple path
                match p.current() {
                    IDENT | T![::] | T![super] | T![self] | T![crate] => p.bump_any(),
                    T![=] => {
                        p.bump_any();
                        match p.current() {
                            c if c.is_literal() => p.bump_any(),
                            T![true] | T![false] => p.bump_any(),
                            _ => {}
                        }
                        break;
                    }
                    _ => break,
                }
            }
        }

        m.complete(p, TOKEN_TREE);
    }

    pub(crate) fn item(p: &mut Parser) {
        items::item_or_macro(p, true, items::ItemFlavor::Mod)
    }

    pub(crate) fn macro_items(p: &mut Parser) {
        let m = p.start();
        items::mod_contents(p, false);
        m.complete(p, MACRO_ITEMS);
    }

    pub(crate) fn macro_stmts(p: &mut Parser) {
        let m = p.start();

        while !p.at(EOF) {
            if p.at(T![;]) {
                p.bump(T![;]);
                continue;
            }

            expressions::stmt(p, expressions::StmtWithSemi::Optional);
        }

        m.complete(p, MACRO_STMTS);
    }
}

pub(crate) fn reparser(
    node: SyntaxKind,
    first_child: Option<SyntaxKind>,
    parent: Option<SyntaxKind>,
) -> Option<fn(&mut Parser)> {
    let res = match node {
        BLOCK_EXPR => expressions::block_expr,
        RECORD_FIELD_DEF_LIST => items::record_field_def_list,
        RECORD_FIELD_LIST => items::record_field_list,
        ENUM_VARIANT_LIST => items::enum_variant_list,
        MATCH_ARM_LIST => items::match_arm_list,
        USE_TREE_LIST => items::use_tree_list,
        EXTERN_ITEM_LIST => items::extern_item_list,
        TOKEN_TREE if first_child? == T!['{'] => items::token_tree,
        ASSOC_ITEM_LIST => match parent? {
            IMPL_DEF => items::impl_item_list,
            TRAIT_DEF => items::trait_item_list,
            _ => return None,
        },
        ITEM_LIST => items::mod_item_list,
        _ => return None,
    };
    Some(res)
}

#[derive(Clone, Copy, PartialEq, Eq)]
enum BlockLike {
    Block,
    NotBlock,
}

impl BlockLike {
    fn is_block(self) -> bool {
        self == BlockLike::Block
    }
}

fn opt_visibility(p: &mut Parser) -> bool {
    match p.current() {
        T![pub] => {
            let m = p.start();
            p.bump(T![pub]);
            if p.at(T!['(']) {
                match p.nth(1) {
                    // test crate_visibility
                    // pub(crate) struct S;
                    // pub(self) struct S;
                    // pub(self) struct S;
                    // pub(self) struct S;
                    T![crate] | T![self] | T![super] => {
                        p.bump_any();
                        p.bump_any();
                        p.expect(T![')']);
                    }
                    T![in] => {
                        p.bump_any();
                        p.bump_any();
                        paths::use_path(p);
                        p.expect(T![')']);
                    }
                    _ => (),
                }
            }
            m.complete(p, VISIBILITY);
        }
        // test crate_keyword_vis
        // crate fn main() { }
        // struct S { crate field: u32 }
        // struct T(crate u32);
        //
        // test crate_keyword_path
        // fn foo() { crate::foo(); }
        T![crate] if !p.nth_at(1, T![::]) => {
            let m = p.start();
            p.bump(T![crate]);
            m.complete(p, VISIBILITY);
        }
        _ => return false,
    }
    true
}

fn opt_alias(p: &mut Parser) {
    if p.at(T![as]) {
        let m = p.start();
        p.bump(T![as]);
        if !p.eat(T![_]) {
            name(p);
        }
        m.complete(p, RENAME);
    }
}

fn abi(p: &mut Parser) {
    assert!(p.at(T![extern]));
    let abi = p.start();
    p.bump(T![extern]);
    match p.current() {
        STRING | RAW_STRING => p.bump_any(),
        _ => (),
    }
    abi.complete(p, ABI);
}

fn opt_fn_ret_type(p: &mut Parser) -> bool {
    if p.at(T![->]) {
        let m = p.start();
        p.bump(T![->]);
        types::type_no_bounds(p);
        m.complete(p, RET_TYPE);
        true
    } else {
        false
    }
}

fn name_r(p: &mut Parser, recovery: TokenSet) {
    if p.at(IDENT) {
        let m = p.start();
        p.bump(IDENT);
        m.complete(p, NAME);
    } else {
        p.err_recover("expected a name", recovery);
    }
}

fn name(p: &mut Parser) {
    name_r(p, TokenSet::EMPTY)
}

fn name_ref(p: &mut Parser) {
    if p.at(IDENT) {
        let m = p.start();
        p.bump(IDENT);
        m.complete(p, NAME_REF);
    } else {
        p.err_and_bump("expected identifier");
    }
}

fn name_ref_or_index(p: &mut Parser) {
    assert!(p.at(IDENT) || p.at(INT_NUMBER));
    let m = p.start();
    p.bump_any();
    m.complete(p, NAME_REF);
}

fn error_block(p: &mut Parser, message: &str) {
    assert!(p.at(T!['{']));
    let m = p.start();
    p.error(message);
    p.bump(T!['{']);
    expressions::expr_block_contents(p);
    p.eat(T!['}']);
    m.complete(p, ERROR);
}