diff options
author | Aleksey Kladov <[email protected]> | 2018-08-04 14:58:22 +0100 |
---|---|---|
committer | Aleksey Kladov <[email protected]> | 2018-08-04 14:58:22 +0100 |
commit | c5483822520e9c754f3ec8b9eb8e68bd5ef7c373 (patch) | |
tree | 5c1b0cd74781a4289c3b6269d5e77e9fc69eadd1 /src/grammar/expressions/mod.rs | |
parent | 23cbe7fd4a048ba44aee647b3b7d5a7f3aa575da (diff) |
move atoms to a separate file
Diffstat (limited to 'src/grammar/expressions/mod.rs')
-rw-r--r-- | src/grammar/expressions/mod.rs | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/src/grammar/expressions/mod.rs b/src/grammar/expressions/mod.rs new file mode 100644 index 000000000..f2b0c36f5 --- /dev/null +++ b/src/grammar/expressions/mod.rs | |||
@@ -0,0 +1,255 @@ | |||
1 | mod atom; | ||
2 | |||
3 | use super::*; | ||
4 | pub(super) use self::atom::literal; | ||
5 | |||
6 | const EXPR_FIRST: TokenSet = UNARY_EXPR_FIRST; | ||
7 | |||
8 | pub(super) fn expr(p: &mut Parser) { | ||
9 | expr_bp(p, 1) | ||
10 | } | ||
11 | |||
12 | // test block | ||
13 | // fn a() {} | ||
14 | // fn b() { let _ = 1; } | ||
15 | // fn c() { 1; 2; } | ||
16 | // fn d() { 1; 2 } | ||
17 | pub(super) fn block(p: &mut Parser) { | ||
18 | if !p.at(L_CURLY) { | ||
19 | p.error("expected block"); | ||
20 | return; | ||
21 | } | ||
22 | atom::block_expr(p); | ||
23 | } | ||
24 | |||
25 | // test expr_binding_power | ||
26 | // fn foo() { | ||
27 | // 1 + 2 * 3 == 1 * 2 + 3 | ||
28 | // } | ||
29 | fn bp_of(op: SyntaxKind) -> u8 { | ||
30 | match op { | ||
31 | EQEQ | NEQ => 1, | ||
32 | MINUS | PLUS => 2, | ||
33 | STAR | SLASH => 3, | ||
34 | _ => 0 | ||
35 | } | ||
36 | } | ||
37 | |||
38 | // Parses expression with binding power of at least bp. | ||
39 | fn expr_bp(p: &mut Parser, bp: u8) { | ||
40 | let mut lhs = match unary_expr(p) { | ||
41 | Some(lhs) => lhs, | ||
42 | None => return, | ||
43 | }; | ||
44 | |||
45 | loop { | ||
46 | let op_bp = bp_of(p.current()); | ||
47 | if op_bp < bp { | ||
48 | break; | ||
49 | } | ||
50 | lhs = bin_expr(p, lhs, op_bp); | ||
51 | } | ||
52 | } | ||
53 | |||
54 | const UNARY_EXPR_FIRST: TokenSet = | ||
55 | token_set_union![ | ||
56 | token_set![AMPERSAND, STAR, EXCL], | ||
57 | atom::ATOM_EXPR_FIRST, | ||
58 | ]; | ||
59 | |||
60 | fn unary_expr(p: &mut Parser) -> Option<CompletedMarker> { | ||
61 | let done = match p.current() { | ||
62 | AMPERSAND => ref_expr(p), | ||
63 | STAR => deref_expr(p), | ||
64 | EXCL => not_expr(p), | ||
65 | _ => { | ||
66 | let lhs = atom::atom_expr(p)?; | ||
67 | postfix_expr(p, lhs) | ||
68 | } | ||
69 | }; | ||
70 | Some(done) | ||
71 | } | ||
72 | |||
73 | fn postfix_expr(p: &mut Parser, mut lhs: CompletedMarker) -> CompletedMarker { | ||
74 | loop { | ||
75 | lhs = match p.current() { | ||
76 | L_PAREN => call_expr(p, lhs), | ||
77 | DOT if p.nth(1) == IDENT => if p.nth(2) == L_PAREN { | ||
78 | method_call_expr(p, lhs) | ||
79 | } else { | ||
80 | field_expr(p, lhs) | ||
81 | }, | ||
82 | DOT if p.nth(1) == INT_NUMBER => field_expr(p, lhs), | ||
83 | QUESTION => try_expr(p, lhs), | ||
84 | _ => break, | ||
85 | } | ||
86 | } | ||
87 | lhs | ||
88 | } | ||
89 | |||
90 | // test ref_expr | ||
91 | // fn foo() { | ||
92 | // let _ = &1; | ||
93 | // let _ = &mut &f(); | ||
94 | // } | ||
95 | fn ref_expr(p: &mut Parser) -> CompletedMarker { | ||
96 | assert!(p.at(AMPERSAND)); | ||
97 | let m = p.start(); | ||
98 | p.bump(); | ||
99 | p.eat(MUT_KW); | ||
100 | expr(p); | ||
101 | m.complete(p, REF_EXPR) | ||
102 | } | ||
103 | |||
104 | // test deref_expr | ||
105 | // fn foo() { | ||
106 | // **&1; | ||
107 | // } | ||
108 | fn deref_expr(p: &mut Parser) -> CompletedMarker { | ||
109 | assert!(p.at(STAR)); | ||
110 | let m = p.start(); | ||
111 | p.bump(); | ||
112 | expr(p); | ||
113 | m.complete(p, DEREF_EXPR) | ||
114 | } | ||
115 | |||
116 | // test not_expr | ||
117 | // fn foo() { | ||
118 | // !!true; | ||
119 | // } | ||
120 | fn not_expr(p: &mut Parser) -> CompletedMarker { | ||
121 | assert!(p.at(EXCL)); | ||
122 | let m = p.start(); | ||
123 | p.bump(); | ||
124 | expr(p); | ||
125 | m.complete(p, NOT_EXPR) | ||
126 | } | ||
127 | |||
128 | // test call_expr | ||
129 | // fn foo() { | ||
130 | // let _ = f(); | ||
131 | // let _ = f()(1)(1, 2,); | ||
132 | // } | ||
133 | fn call_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker { | ||
134 | assert!(p.at(L_PAREN)); | ||
135 | let m = lhs.precede(p); | ||
136 | arg_list(p); | ||
137 | m.complete(p, CALL_EXPR) | ||
138 | } | ||
139 | |||
140 | // test method_call_expr | ||
141 | // fn foo() { | ||
142 | // x.foo(); | ||
143 | // y.bar(1, 2,); | ||
144 | // } | ||
145 | fn method_call_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker { | ||
146 | assert!(p.at(DOT) && p.nth(1) == IDENT && p.nth(2) == L_PAREN); | ||
147 | let m = lhs.precede(p); | ||
148 | p.bump(); | ||
149 | name_ref(p); | ||
150 | arg_list(p); | ||
151 | m.complete(p, METHOD_CALL_EXPR) | ||
152 | } | ||
153 | |||
154 | // test field_expr | ||
155 | // fn foo() { | ||
156 | // x.foo; | ||
157 | // x.0.bar; | ||
158 | // } | ||
159 | fn field_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker { | ||
160 | assert!(p.at(DOT) && (p.nth(1) == IDENT || p.nth(1) == INT_NUMBER)); | ||
161 | let m = lhs.precede(p); | ||
162 | p.bump(); | ||
163 | if p.at(IDENT) { | ||
164 | name_ref(p) | ||
165 | } else { | ||
166 | p.bump() | ||
167 | } | ||
168 | m.complete(p, FIELD_EXPR) | ||
169 | } | ||
170 | |||
171 | // test try_expr | ||
172 | // fn foo() { | ||
173 | // x?; | ||
174 | // } | ||
175 | fn try_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker { | ||
176 | assert!(p.at(QUESTION)); | ||
177 | let m = lhs.precede(p); | ||
178 | p.bump(); | ||
179 | m.complete(p, TRY_EXPR) | ||
180 | } | ||
181 | |||
182 | fn arg_list(p: &mut Parser) { | ||
183 | assert!(p.at(L_PAREN)); | ||
184 | let m = p.start(); | ||
185 | p.bump(); | ||
186 | while !p.at(R_PAREN) && !p.at(EOF) { | ||
187 | expr(p); | ||
188 | if !p.at(R_PAREN) && !p.expect(COMMA) { | ||
189 | break; | ||
190 | } | ||
191 | } | ||
192 | p.eat(R_PAREN); | ||
193 | m.complete(p, ARG_LIST); | ||
194 | } | ||
195 | |||
196 | // test path_expr | ||
197 | // fn foo() { | ||
198 | // let _ = a; | ||
199 | // let _ = a::b; | ||
200 | // let _ = ::a::<b>; | ||
201 | // } | ||
202 | fn path_expr(p: &mut Parser) -> CompletedMarker { | ||
203 | assert!(paths::is_path_start(p)); | ||
204 | let m = p.start(); | ||
205 | paths::expr_path(p); | ||
206 | if p.at(L_CURLY) { | ||
207 | struct_lit(p); | ||
208 | m.complete(p, STRUCT_LIT) | ||
209 | } else { | ||
210 | m.complete(p, PATH_EXPR) | ||
211 | } | ||
212 | } | ||
213 | |||
214 | // test struct_lit | ||
215 | // fn foo() { | ||
216 | // S {}; | ||
217 | // S { x, y: 32, }; | ||
218 | // S { x, y: 32, ..Default::default() }; | ||
219 | // } | ||
220 | fn struct_lit(p: &mut Parser) { | ||
221 | assert!(p.at(L_CURLY)); | ||
222 | p.bump(); | ||
223 | while !p.at(EOF) && !p.at(R_CURLY) { | ||
224 | match p.current() { | ||
225 | IDENT => { | ||
226 | let m = p.start(); | ||
227 | name_ref(p); | ||
228 | if p.eat(COLON) { | ||
229 | expr(p); | ||
230 | } | ||
231 | m.complete(p, STRUCT_LIT_FIELD); | ||
232 | } | ||
233 | DOTDOT => { | ||
234 | p.bump(); | ||
235 | expr(p); | ||
236 | } | ||
237 | _ => p.err_and_bump("expected identifier"), | ||
238 | } | ||
239 | if !p.at(R_CURLY) { | ||
240 | p.expect(COMMA); | ||
241 | } | ||
242 | } | ||
243 | p.expect(R_CURLY); | ||
244 | } | ||
245 | |||
246 | fn bin_expr(p: &mut Parser, lhs: CompletedMarker, bp: u8) -> CompletedMarker { | ||
247 | assert!(match p.current() { | ||
248 | MINUS | PLUS | STAR | SLASH | EQEQ | NEQ => true, | ||
249 | _ => false, | ||
250 | }); | ||
251 | let m = lhs.precede(p); | ||
252 | p.bump(); | ||
253 | expr_bp(p, bp); | ||
254 | m.complete(p, BIN_EXPR) | ||
255 | } | ||