aboutsummaryrefslogtreecommitdiff
path: root/src/parser/grammar/items/mod.rs
blob: d059833a07da30fd4a1649bb3b618725776e518e (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
use super::*;

mod consts;
mod structs;
mod traits;
mod use_item;

pub(super) fn mod_contents(p: &mut Parser, stop_on_r_curly: bool) {
    attributes::inner_attributes(p);
    while !p.at(EOF) && !(stop_on_r_curly && p.at(R_CURLY)) {
        item(p);
    }
}

pub(super) const ITEM_FIRST: TokenSet =
    token_set![EXTERN_KW, MOD_KW, USE_KW, STRUCT_KW, ENUM_KW, FN_KW, PUB_KW, POUND];

fn item(p: &mut Parser) {
    let item = p.start();
    attributes::outer_attributes(p);
    visibility(p);
    let la = p.nth(1);
    let item_kind = match p.current() {
        USE_KW => {
            use_item::use_item(p);
            USE_ITEM
        }
        // test extern_crate
        // extern crate foo;
        EXTERN_KW if la == CRATE_KW => {
            extern_crate_item(p);
            EXTERN_CRATE_ITEM
        }
        EXTERN_KW => {
            abi(p);
            match p.current() {
                // test extern_fn
                // extern fn foo() {}
                FN_KW => {
                    fn_item(p);
                    FN_ITEM
                }
                // test extern_block
                // extern {}
                L_CURLY => {
                    extern_block(p);
                    EXTERN_BLOCK
                }
                // test extern_struct
                // extern struct Foo;
                _ => {
                    item.abandon(p);
                    p.error("expected `fn` or `{`");
                    return;
                }
            }
        }
        STATIC_KW => {
            consts::static_item(p);
            STATIC_ITEM
        }
        CONST_KW => match p.nth(1) {
            // test const_fn
            // const fn foo() {}
            FN_KW => {
                p.bump();
                fn_item(p);
                FN_ITEM
            }
            // test const_unsafe_fn
            // const unsafe fn foo() {}
            UNSAFE_KW if p.nth(2) == FN_KW => {
                p.bump();
                p.bump();
                fn_item(p);
                FN_ITEM
            }
            _ => {
                consts::const_item(p);
                CONST_ITEM
            }
        },
        UNSAFE_KW => {
            p.bump();
            let la = p.nth(1);
            match p.current() {
                // test unsafe_trait
                // unsafe trait T {}
                TRAIT_KW => {
                    traits::trait_item(p);
                    TRAIT_ITEM
                }

                // test unsafe_auto_trait
                // unsafe auto trait T {}
                IDENT if p.at_contextual_kw("auto") && la == TRAIT_KW => {
                    p.bump_remap(AUTO_KW);
                    traits::trait_item(p);
                    TRAIT_ITEM
                }

                // test unsafe_impl
                // unsafe impl Foo {}
                IMPL_KW => {
                    traits::impl_item(p);
                    IMPL_ITEM
                }

                // test unsafe_default_impl
                // unsafe default impl Foo {}
                IDENT if p.at_contextual_kw("default") && la == IMPL_KW => {
                    p.bump_remap(DEFAULT_KW);
                    traits::impl_item(p);
                    IMPL_ITEM
                }

                // test unsafe_extern_fn
                // unsafe extern "C" fn foo() {}
                EXTERN_KW => {
                    abi(p);
                    if !p.at(FN_KW) {
                        item.abandon(p);
                        p.error("expected function");
                        return;
                    }
                    fn_item(p);
                    FN_ITEM
                }

                // test unsafe_fn
                // unsafe fn foo() {}
                FN_KW => {
                    fn_item(p);
                    FN_ITEM
                }

                t => {
                    item.abandon(p);
                    let message = "expected `trait`, `impl` or `fn`";

                    // test unsafe_block_in_mod
                    // fn foo(){} unsafe { } fn bar(){}
                    if t == L_CURLY {
                        error_block(p, message);
                    } else {
                        p.error(message);
                    }
                    return;
                }
            }
        }
        FN_KW => {
            fn_item(p);
            FN_ITEM
        }
        TYPE_KW => {
            type_item(p);
            TYPE_ITEM
        }
        MOD_KW => {
            mod_item(p);
            MOD_ITEM
        }
        STRUCT_KW => {
            structs::struct_item(p);
            STRUCT_ITEM
        }
        ENUM_KW => {
            structs::enum_item(p);
            ENUM_ITEM
        }
        L_CURLY => {
            item.abandon(p);
            error_block(p, "expected item");
            return;
        }
        err_token => {
            item.abandon(p);
            let message = if err_token == SEMI {
                //TODO: if the item is incomplete, this message is misleading
                "expected item, found `;`\n\
                 consider removing this semicolon"
            } else {
                "expected item"
            };
            p.err_and_bump(message);
            return;
        }
    };
    item.complete(p, item_kind);
}

fn extern_crate_item(p: &mut Parser) {
    assert!(p.at(EXTERN_KW));
    p.bump();
    assert!(p.at(CRATE_KW));
    p.bump();
    name(p);
    alias(p);
    p.expect(SEMI);
}

fn extern_block(p: &mut Parser) {
    assert!(p.at(L_CURLY));
    p.bump();
    p.expect(R_CURLY);
}


fn fn_item(p: &mut Parser) {
    assert!(p.at(FN_KW));
    p.bump();

    name(p);
    if p.at(L_PAREN) {
        fn_value_parameters(p);
    } else {
        p.error("expected function arguments");
    }
    // test fn_item_ret_type
    // fn foo() {}
    // fn bar() -> () {}
    fn_ret_type(p);
    block(p);

    fn block(p: &mut Parser) {
        if !p.at(L_CURLY) {
            p.error("expected block");
        }
        let m = p.start();
        p.bump();
        while !p.at(EOF) && !p.at(R_CURLY) {
            match p.current() {
                LET_KW => let_stmt(p),
                _ => p.err_and_bump("expected statement"),
            }
        }
        p.expect(R_CURLY);
        m.complete(p, BLOCK);
    }

    fn let_stmt(p: &mut Parser) {
        assert!(p.at(LET_KW));
        let m = p.start();
        p.bump();
        patterns::pattern(p);
        p.expect(EQ);
        expressions::expr(p);
        p.expect(SEMI);
        m.complete(p, LET_STMT);
    }
}

// test type_item
// type Foo = Bar;
fn type_item(p: &mut Parser) {
    assert!(p.at(TYPE_KW));
    p.bump();

    name(p);

    // test type_item_type_params
    // type Result<T> = ();
    type_params::list(p);

    // test type_item_where_clause
    // type Foo where Foo: Copy = ();
    type_params::where_clause(p);

    p.expect(EQ);
    types::type_(p);
    p.expect(SEMI);
}

fn mod_item(p: &mut Parser) {
    assert!(p.at(MOD_KW));
    p.bump();

    name(p);
    if !p.eat(SEMI) {
        if p.expect(L_CURLY) {
            mod_contents(p, true);
            p.expect(R_CURLY);
        }
    }
}