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
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
|
lex
literal `fn `use `let `mut `if `else `struct
literal `loop `while `for `in
literal `true `false
literal `ref `match `as `impl
literal `crate `self `return
literal `; `:: `( `) `{ `} `. `, `@
literal `[ `] `:
literal `-> `=>
literal `< `>
literal `?
literal `- `+ `/ `* `% `! `&mut
literal `^ `| `&
literal `>> `<<
literal `== `!= `>= `<=
literal `|| `&&
literal `.. `..= `...
literal `=
literal `+= `-= `*= `/= `%= `&= `|= `^= `<<= `>>=
literal `_
token id / [A-Za-z_] [A-Za-z_0-9]* /
token string / '"' ( [^\"] | '\\' any )* '"' /
token char / "'" ( [^\'] | '\\' any ) "'" /
token lifetime / "'" id /
token number / [0-9]+ /
token float / [0-9]+ '.' [0-9]+ /
ignore / "//" [^\n]* '\n' /
ignore / [ \t\n]+ /
end
#
# Use statments
#
def sp_tail
[sp_tail `:: id]
| []
def simple_path
[id sp_tail]
def use_list_tail
[use_list_tail `, use_tree]
| []
def use_path_opt
[simple_path `::]
| [`::]
| []
def use_as_opt
[`as id]
| [`as `_]
| []
def use_tree
[use_path_opt `*]
| [use_path_opt `{ use_tree use_list_tail `}]
| [simple_path use_as_opt]
def use_declaration
[`use use_tree `;]
#
# Patterns
#
def literal_pattern
[`true]
| [`false]
| [char]
| [string]
| [number]
| [float]
def identifier_pattern
[opt_ref opt_mut id]
| [opt_ref opt_mut id `@ pattern]
def wildcard_pattern
[`_]
def range_pattern_bound
[literal_pattern]
def range_pattern
[range_pattern_bound `..= range_pattern_bound]
| [range_pattern_bound `... range_pattern_bound]
def reference_pattern
[`& opt_mut pattern]
| [`&& opt_mut pattern]
#
# struct pattern
#
def struct_pattern_field
[number `: pattern]
| [id `: pattern]
| [opt_ref opt_mut id]
def struct_pattern_fields
[struct_pattern_fields `, struct_pattern_field]
| [struct_pattern_field]
def struct_pattern_et_cetera
[`..]
def struct_pattern_elements
[struct_pattern_fields]
| [struct_pattern_fields `, ]
| [struct_pattern_fields `, struct_pattern_et_cetera]
| [struct_pattern_et_cetera]
def opt_struct_pattern_elements
[struct_pattern_elements]
| []
def struct_pattern
[path_in_expression `{ opt_struct_pattern_elements `}]
def opt_comma
[`,]
| []
def tuple_struct_item
[pattern]
| [`..]
def tuple_struct_items
[tuple_struct_items `, tuple_struct_item]
| [tuple_struct_item]
def tuple_struct_pattern
[path_in_expression `( tuple_struct_items opt_comma `)]
def tuple_pattern_item
[pattern]
| [`..]
def tuple_pattern_items
[tuple_pattern_items `, tuple_pattern_item]
| [tuple_pattern_item]
def tuple_pattern
[`( tuple_pattern_item `, `)]
| [`( tuple_pattern_item `, tuple_pattern_items opt_comma `)]
def grouped_pattern
[`( pattern `)]
def pattern
[literal_pattern]
| [identifier_pattern]
| [wildcard_pattern]
| [range_pattern]
| [reference_pattern]
| [struct_pattern]
| [tuple_struct_pattern]
| [tuple_pattern]
| [grouped_pattern]
# Range Pattern
#
# Match Expressions.
#
def match_expression
[`match expression `{ match_arms? `}]
def match_arms_last
[match_arm `=> block_expression `, ?]
| [match_arm `=> expression `, ?]
def match_arms_first_case
[match_arm `=> block_expression `, ?]
| [match_arm `=> expression `,]
def match_arms_first_list
[match_arms_first_list match_arms_first_case]
| []
def match_arms
[match_arms_first_list match_arms_last]
def match_arm
[match_arm_patterns opt_match_arm_guard]
def match_arms_pattern_tail
[match_arms_pattern_tail `| pattern]
| []
def opt_bar
[`|]
| []
def match_arm_patterns
[opt_bar pattern match_arms_pattern_tail]
def opt_match_arm_guard
[`if expression]
| []
#
# Return expressions
#
def return_expression
[`return]
| [`return expression]
#
# Generic Args
#
def lifetime_tail
[lifetime_tail `, lifetime]
| []
def lifetime_list
[lifetime lifetime_tail]
def opt_type_params
[`< lifetime_list `>]
| [`< type_list `>]
| [`< lifetime_list `, type_list `>]
| []
#
# Function declaration
#
def opt_return
[]
| [ `-> type]
def function
[`fn id opt_generics `( field_list `) opt_return block_expression]
#
# Method declaration
#
def self_param
[opt_mut `self]
| [`& opt_mut `self]
| [`& lifetime opt_mut `self]
| [opt_mut `self `: type]
def opt_field_list
[`, field_list]
| []
def method
[`fn id opt_generics `( self_param opt_field_list `) opt_return block_expression]
#
# Types
#
def qual_tail
[qual_tail `:: id]
| []
def qual_id
[id qual_tail]
def type_id
[id opt_type_params]
def type_path_tail
[type_path_tail `:: type_id]
| []
def type_path
[type_id type_path_tail]
| [`[ type `; expression `]]
| [`[ type `]]
def opt_lifetime
[lifetime]
| []
def type
[type_path]
| [`& opt_lifetime type_path]
| [`&mut type_path]
| [`& lifetime `mut type_path]
| [`( `)]
def type_list
[type_list `, type]
| [type]
def opt_mut
[`mut]
| []
def opt_ref
[`ref]
| []
def opt_type
[`: type]
| []
def block_expr
[`{ statements `}]
def let_rvalue
[expression]
| [`{ statements `}]
def let_stmt
[`let pattern opt_type `= let_rvalue]
def expr_tail
[expr_tail `, expression]
| []
def expr_list
[expression expr_tail]
| []
def _construct
[id `: expression]
def cons_plus
[cons_plus `, _construct]
| [_construct]
def cons_list
[cons_plus]
| []
#
# Expression
#
def path_ident_segment
[id]
| [`self]
| [`crate]
def path_expr_segment
[path_ident_segment]
#| [path_ident_segment `:: generic_args]
def pie_tail
[pie_tail `:: path_expr_segment]
| []
def opt_path_sep
[`::]
| []
def path_in_expression
[opt_path_sep path_expr_segment pie_tail]
def path_expression
[path_in_expression]
#| [qualified_path_in_expression]
# Doesn't really belong in expressions. Macros are a whole pass before. Here
# for now.
def opt_macro
[`!]
| []
def paths
[path_expression]
| [char]
| [string]
| [number]
| [float]
| [id `{ cons_list `}]
| [ `[ number `; number `]]
| [`( `)]
| [`true]
| [`false]
| [`( expression `)]
def func_index
[func_index `. qual_id `( expr_list `)]
| [func_index `. id]
| [func_index `. number]
| [func_index opt_macro `( expr_list `)]
| [func_index opt_macro `[ expr_list `]]
| [paths]
def question
[question `?]
| [func_index]
def unary
[question]
| [`- unary]
| [`* unary]
| [`! unary]
| [`& unary]
| [`&mut unary]
| [`mut unary]
def as
[unary]
def mult
[mult `* as]
| [mult `/ as]
| [mult `% as]
| [as]
def add_sub
[add_sub `- mult]
| [add_sub `+ mult]
| [mult]
def shift
[shift `>> add_sub]
| [shift `<< add_sub]
| [add_sub]
def bitwise_and
[bitwise_and `& shift]
| [shift]
def bitwise_xor
[bitwise_and `^ shift]
| [bitwise_and]
def bitwise_or
[bitwise_and `| shift]
| [bitwise_xor]
def comp_op
[`==] | [`!=]
| [`>] | [`<]
| [`>=] | [`<=]
def comparison
[comparison comp_op bitwise_or]
| [bitwise_or]
def lazy_conjunction
[lazy_conjunction `&& comparison]
| [comparison]
def lazy_disjunction
[lazy_disjunction `|| lazy_conjunction]
| [lazy_conjunction]
def range_expression
[range_expression `.. lazy_disjunction]
| [lazy_disjunction `..]
| [`.. lazy_disjunction]
| [`..]
| [range_expression `..= lazy_disjunction]
| [`..= lazy_disjunction]
| [lazy_disjunction]
# Evaluates right to left.
def assignment_expression
[range_expression `= assignment_expression]
| [range_expression]
def compound_op
[`+=] | [`-=] | [`*=] | [`/=] | [`%=]
| [`&=] | [`|=] | [`^=] | [`<<=] | [`>>=]
# Evaluates right to left.
def compound_expression
[assignment_expression compound_op compound_expression]
| [assignment_expression]
def expression
[expression_without_block]
| [expression_with_block]
#
# Statements
#
def block_expression
[`{ statements? `}]
def let_statement
[`let pattern opt_type `= let_rvalue `;]
def expression_without_block
[compound_expression `? ?]
| [return_expression]
def expression_with_block
[block_expression]
| [loop_expression]
| [if_expression]
| [if_let_expression]
| [match_expression]
def expression_statement
[expression_without_block `;]
| [expression_with_block]
def statement
[`;]
| [let_statement]
| [expression_statement]
def statements
[statement+]
| [statement+ expression_without_block]
| [expression_without_block]
def loop_expression
[`loop block_expression]
| [`while expression block_expression]
| [`while `let match_arm_patterns `= expression block_expression]
| [`for pattern `in expression block_expression]
def if_expression
[`if expression block_expression opt_else_expression]
def opt_else_expression
[`else block_expression]
| [`else if_expression]
| [`else if_let_expression]
| []
def if_let_expression
[`if `let match_arm_patterns `= expression block_expression]
def field
[id `: type]
def field_plus
[field_plus `, field]
| [field]
def field_list
[field_plus]
| []
#
# Lifetime Params
#
def lifetime_param
[lifetime]
def lifetime_param_tail
[lifetime_param_tail `, lifetime_param]
| []
def lifetime_param_list
[lifetime_param lifetime_param_tail]
#
# Type Params
#
def opt_eq_type
[`= type]
| []
def type_param
[id opt_eq_type]
def type_param_tail
[type_param_tail `, type_param]
| []
def type_param_list
[type_param type_param_tail]
#
# Generics
#
def generic_params
[lifetime_param_list `, type_param_list]
| [lifetime_param_list]
| [type_param_list]
| []
def opt_generics
[`< generic_params `>]
| []
#
# Tuple List
#
def tuple_field_tail
[tuple_field_tail `, type]
| []
def tuple_field_list
[type tuple_field_tail]
| []
#
# Structure
#
def structure
[`struct id opt_generics `{ field_list `}]
| [`struct id opt_generics `;]
| [`struct id opt_generics `( tuple_field_list `) `; ]
#
# Implementation
#
def inherent_impl_item
[function]
| [method]
def inherent_impl
[`impl opt_generics type `{ inherent_impl_item* `}]
def trait_impl
[]
def implementation
[inherent_impl]
#| [trait_impl]
#
# All Items.
#
def item
[function] commit
| [structure] commit
| [implementation] commit
| [use_declaration] commit
def program
[item*]
|
