1
|
|
|
<?php |
2
|
|
|
/** |
3
|
|
|
* This file is part of Railt package. |
4
|
|
|
* |
5
|
|
|
* For the full copyright and license information, please view the LICENSE |
6
|
|
|
* file that was distributed with this source code. |
7
|
|
|
*/ |
8
|
|
|
declare(strict_types=1); |
9
|
|
|
|
10
|
|
|
namespace Railt\Compiler\Grammar; |
11
|
|
|
|
12
|
|
|
use Railt\Compiler\Exception\GrammarException; |
13
|
|
|
use Railt\Compiler\Grammar\Builder\AbstractBuilder; |
14
|
|
|
use Railt\Compiler\Grammar\Builder\Alternation; |
15
|
|
|
use Railt\Compiler\Grammar\Builder\Concatenation; |
16
|
|
|
use Railt\Compiler\Grammar\Builder\Repetition; |
17
|
|
|
use Railt\Compiler\Grammar\Builder\Terminal; |
18
|
|
|
use Railt\Compiler\Grammar\Delegate\RuleDelegate; |
19
|
|
|
use Railt\Lexer\Result\Eoi; |
20
|
|
|
use Railt\Parser\Rule\Rule; |
21
|
|
|
|
22
|
|
|
/** |
23
|
|
|
* Analyze rules and transform them into atomic rules operations. |
24
|
|
|
*/ |
25
|
|
|
class Analyzer |
26
|
|
|
{ |
27
|
|
|
/** |
28
|
|
|
* @var array|RuleDelegate[] |
29
|
|
|
*/ |
30
|
|
|
protected $rules = []; |
31
|
|
|
|
32
|
|
|
/** |
33
|
|
|
* Parsed rules. |
34
|
|
|
* @var array|AbstractBuilder[] |
35
|
|
|
*/ |
36
|
|
|
protected $parsedRules; |
37
|
|
|
|
38
|
|
|
/** |
39
|
|
|
* Counter to auto-name transitional rules. |
40
|
|
|
* @var int |
41
|
|
|
*/ |
42
|
|
|
protected $transitionalRuleCounter = 0; |
43
|
|
|
|
44
|
|
|
/** |
45
|
|
|
* Rule name being analyzed. |
46
|
|
|
* @var string |
47
|
|
|
*/ |
48
|
|
|
private $ruleName; |
49
|
|
|
|
50
|
|
|
/** |
51
|
|
|
* @param RuleDelegate $delegate |
52
|
|
|
*/ |
53
|
|
|
public function addRuleDelegate(RuleDelegate $delegate): void |
54
|
|
|
{ |
55
|
|
|
$this->rules[$delegate->getRuleName()] = $delegate; |
56
|
|
|
} |
57
|
|
|
|
58
|
|
|
/** |
59
|
|
|
* Build the analyzer of the rules (does not analyze the rules). |
60
|
|
|
* |
61
|
|
|
* @return Rule[]|\Traversable |
62
|
|
|
* @throws GrammarException |
63
|
|
|
*/ |
64
|
|
|
public function analyze(): iterable |
65
|
|
|
{ |
66
|
|
|
if (\count($this->rules) === 0) { |
67
|
|
|
throw new GrammarException('No rules specified'); |
68
|
|
|
} |
69
|
|
|
|
70
|
|
|
$this->parsedRules = []; |
71
|
|
|
|
72
|
|
|
foreach ($this->rules as $delegate) { |
73
|
|
|
$this->ruleName = $delegate->getRuleName(); |
74
|
|
|
$nodeId = $delegate->isKept() ? $delegate->getRuleName() : null; |
75
|
|
|
|
76
|
|
|
$pNodeId = $nodeId; |
77
|
|
|
$rule = $this->rule($delegate->getInnerTokens(), $pNodeId); |
78
|
|
|
|
79
|
|
|
if ($rule === null) { |
80
|
|
|
$error = \sprintf('Error while parsing rule %s.', $delegate->getRuleName()); |
81
|
|
|
throw new GrammarException($error, 1); |
82
|
|
|
} |
83
|
|
|
|
84
|
|
|
$zeRule = $this->parsedRules[$rule]; |
85
|
|
|
$zeRule->setName($delegate->getRuleName()); |
86
|
|
|
|
87
|
|
|
if ($nodeId !== null) { |
88
|
|
|
$zeRule->setDefaultId($nodeId); |
89
|
|
|
} |
90
|
|
|
|
91
|
|
|
unset($this->parsedRules[$rule]); |
92
|
|
|
$this->parsedRules[$delegate->getRuleName()] = $zeRule; |
93
|
|
|
} |
94
|
|
|
|
95
|
|
|
foreach ($this->parsedRules as $builder) { |
96
|
|
|
yield $builder->build(); |
97
|
|
|
} |
98
|
|
|
} |
99
|
|
|
|
100
|
|
|
/** |
101
|
|
|
* Implementation of “rule”. |
102
|
|
|
* |
103
|
|
|
* @param LookaheadIterator $tokens |
104
|
|
|
* @param string|null $pNodeId |
105
|
|
|
* @return string|int|null |
106
|
|
|
* @throws GrammarException |
107
|
|
|
*/ |
108
|
|
|
protected function rule(LookaheadIterator $tokens, &$pNodeId) |
109
|
|
|
{ |
110
|
|
|
return $this->choice($tokens, $pNodeId); |
111
|
|
|
} |
112
|
|
|
|
113
|
|
|
/** |
114
|
|
|
* Implementation of “choice”. |
115
|
|
|
* |
116
|
|
|
* @param LookaheadIterator $tokens |
117
|
|
|
* @param string|null $pNodeId |
118
|
|
|
* @return string|int|null |
119
|
|
|
* @throws GrammarException |
120
|
|
|
*/ |
121
|
|
|
protected function choice(LookaheadIterator $tokens, &$pNodeId) |
122
|
|
|
{ |
123
|
|
|
$children = []; |
124
|
|
|
|
125
|
|
|
// concatenation() … |
126
|
|
|
$nNodeId = $pNodeId; |
127
|
|
|
$rule = $this->concatenation($tokens, $nNodeId); |
128
|
|
|
|
129
|
|
|
if ($rule === null) { |
130
|
|
|
return null; |
131
|
|
|
} |
132
|
|
|
|
133
|
|
|
if ($nNodeId !== null) { |
134
|
|
|
$this->parsedRules[$rule]->setNodeId($nNodeId); |
135
|
|
|
} |
136
|
|
|
|
137
|
|
|
$children[] = $rule; |
138
|
|
|
$others = false; |
139
|
|
|
|
140
|
|
|
// … ( ::or:: concatenation() )* |
141
|
|
|
while ($tokens->current()->getName() === Parser::T_OR) { |
142
|
|
|
$tokens->next(); |
143
|
|
|
$others = true; |
144
|
|
|
$nNodeId = $pNodeId; |
145
|
|
|
$rule = $this->concatenation($tokens, $nNodeId); |
146
|
|
|
|
147
|
|
|
if ($rule === null) { |
148
|
|
|
return null; |
149
|
|
|
} |
150
|
|
|
|
151
|
|
|
if ($nNodeId !== null) { |
152
|
|
|
$this->parsedRules[$rule]->setNodeId($nNodeId); |
153
|
|
|
} |
154
|
|
|
|
155
|
|
|
$children[] = $rule; |
156
|
|
|
} |
157
|
|
|
|
158
|
|
|
$pNodeId = null; |
159
|
|
|
|
160
|
|
|
if ($others === false) { |
161
|
|
|
return $rule; |
162
|
|
|
} |
163
|
|
|
|
164
|
|
|
$name = $this->transitionalRuleCounter++; |
165
|
|
|
|
166
|
|
|
$this->parsedRules[$name] = new Alternation($name, $children); |
167
|
|
|
|
168
|
|
|
return $name; |
169
|
|
|
} |
170
|
|
|
|
171
|
|
|
/** |
172
|
|
|
* Implementation of “concatenation”. |
173
|
|
|
* |
174
|
|
|
* @param LookaheadIterator $tokens |
175
|
|
|
* @param string|null $pNodeId |
176
|
|
|
* @return string|int|null |
177
|
|
|
* @throws GrammarException |
178
|
|
|
*/ |
179
|
|
|
protected function concatenation(LookaheadIterator $tokens, &$pNodeId) |
180
|
|
|
{ |
181
|
|
|
$children = []; |
182
|
|
|
|
183
|
|
|
// repetition() … |
184
|
|
|
$rule = $this->repetition($tokens, $pNodeId); |
185
|
|
|
|
186
|
|
|
if ($rule === null) { |
187
|
|
|
return null; |
188
|
|
|
} |
189
|
|
|
|
190
|
|
|
$children[] = $rule; |
191
|
|
|
$others = false; |
192
|
|
|
|
193
|
|
|
// … repetition()* |
194
|
|
|
while (null !== $r1 = $this->repetition($tokens, $pNodeId)) { |
195
|
|
|
$children[] = $r1; |
196
|
|
|
$others = true; |
197
|
|
|
} |
198
|
|
|
|
199
|
|
|
if ($others === false && $pNodeId === null) { |
200
|
|
|
return $rule; |
201
|
|
|
} |
202
|
|
|
|
203
|
|
|
$name = $this->transitionalRuleCounter++; |
204
|
|
|
|
205
|
|
|
$this->parsedRules[$name] = new Concatenation($name, $children); |
206
|
|
|
|
207
|
|
|
return $name; |
208
|
|
|
} |
209
|
|
|
|
210
|
|
|
/** |
211
|
|
|
* Implementation of “repetition”. |
212
|
|
|
* |
213
|
|
|
* @param LookaheadIterator $tokens |
214
|
|
|
* @param string|null $pNodeId |
215
|
|
|
* @return string|int|null |
216
|
|
|
* @throws GrammarException |
217
|
|
|
*/ |
218
|
|
|
protected function repetition(LookaheadIterator $tokens, &$pNodeId) |
219
|
|
|
{ |
220
|
|
|
[$min, $max] = [null, null]; |
|
|
|
|
221
|
|
|
|
222
|
|
|
// simple() … |
223
|
|
|
$children = $this->simple($tokens, $pNodeId); |
224
|
|
|
|
225
|
|
|
if ($children === null) { |
226
|
|
|
return null; |
227
|
|
|
} |
228
|
|
|
|
229
|
|
|
// … quantifier()? |
230
|
|
|
switch ($tokens->current()->getName()) { |
231
|
|
|
case Parser::T_REPEAT_ZERO_OR_ONE: |
232
|
|
|
[$min, $max] = [0, 1]; |
|
|
|
|
233
|
|
|
$tokens->next(); |
234
|
|
|
break; |
235
|
|
|
|
236
|
|
|
case Parser::T_REPEAT_ONE_OR_MORE: |
237
|
|
|
[$min, $max] = [1, -1]; |
|
|
|
|
238
|
|
|
$tokens->next(); |
239
|
|
|
break; |
240
|
|
|
|
241
|
|
|
case Parser::T_REPEAT_ZERO_OR_MORE: |
242
|
|
|
[$min, $max] = [0, -1]; |
|
|
|
|
243
|
|
|
$tokens->next(); |
244
|
|
|
break; |
245
|
|
|
|
246
|
|
|
case Parser::T_REPEAT_N_TO_M: |
247
|
|
|
$min = (int)$tokens->current()->getValue(1); |
248
|
|
|
$max = (int)$tokens->current()->getValue(2); |
249
|
|
|
$tokens->next(); |
250
|
|
|
break; |
251
|
|
|
|
252
|
|
|
case Parser::T_REPEAT_ZERO_TO_M: |
253
|
|
|
[$min, $max] = [0, (int)$tokens->current()->getValue(1)]; |
|
|
|
|
254
|
|
|
$tokens->next(); |
255
|
|
|
break; |
256
|
|
|
|
257
|
|
|
case Parser::T_REPEAT_N_OR_MORE: |
258
|
|
|
[$min, $max] = [(int)$tokens->current()->getValue(1), -1]; |
|
|
|
|
259
|
|
|
$tokens->next(); |
260
|
|
|
break; |
261
|
|
|
|
262
|
|
|
case Parser::T_REPEAT_EXACTLY_N: |
263
|
|
|
$min = $max = (int)$tokens->current()->getValue(1); |
264
|
|
|
$tokens->next(); |
265
|
|
|
break; |
266
|
|
|
} |
267
|
|
|
|
268
|
|
|
// … <node>? |
269
|
|
|
if ($tokens->current()->getName() === Parser::T_KEPT_NAME) { |
270
|
|
|
$tokens->next(); |
271
|
|
|
$pNodeId = $tokens->current()->getValue(); |
272
|
|
|
$tokens->next(); |
273
|
|
|
} |
274
|
|
|
|
275
|
|
|
if ($min === null) { |
|
|
|
|
276
|
|
|
return $children; |
277
|
|
|
} |
278
|
|
|
|
279
|
|
|
if ($max !== -1 && $max < $min) { |
280
|
|
|
$error = 'Upper bound %d must be greater or equal to lower bound %d in rule %s.'; |
281
|
|
|
$error = \sprintf($error, $max, $min, $this->ruleName); |
|
|
|
|
282
|
|
|
throw new GrammarException($error, 2); |
283
|
|
|
} |
284
|
|
|
|
285
|
|
|
$name = $this->transitionalRuleCounter++; |
286
|
|
|
|
287
|
|
|
$this->parsedRules[$name] = new Repetition($name, $min, $max, $children); |
288
|
|
|
|
289
|
|
|
return $name; |
290
|
|
|
} |
291
|
|
|
|
292
|
|
|
/** |
293
|
|
|
* Implementation of “simple”. |
294
|
|
|
* |
295
|
|
|
* @param LookaheadIterator $tokens |
296
|
|
|
* @param int|string|null $pNodeId |
297
|
|
|
* @return string|int|null |
298
|
|
|
* @throws GrammarException |
299
|
|
|
*/ |
300
|
|
|
protected function simple(LookaheadIterator $tokens, &$pNodeId) |
301
|
|
|
{ |
302
|
|
|
switch ($tokens->current()->getName()) { |
303
|
|
|
case Parser::T_GROUP_OPEN: |
304
|
|
|
return $this->group($tokens, $pNodeId); |
305
|
|
|
|
306
|
|
|
case Parser::T_TOKEN_SKIPPED: |
307
|
|
|
return $this->token($tokens, false); |
308
|
|
|
|
309
|
|
|
case Parser::T_TOKEN_KEPT: |
310
|
|
|
return $this->token($tokens, true); |
311
|
|
|
|
312
|
|
|
case Parser::T_INVOKE: |
313
|
|
|
return $this->invoke($tokens); |
314
|
|
|
|
315
|
|
|
default: |
316
|
|
|
return null; |
317
|
|
|
} |
318
|
|
|
} |
319
|
|
|
|
320
|
|
|
/** |
321
|
|
|
* @param LookaheadIterator $tokens |
322
|
|
|
* @param int|string|null $pNodeId |
323
|
|
|
* @return int|null|string |
324
|
|
|
* @throws GrammarException |
325
|
|
|
*/ |
326
|
|
|
protected function group(LookaheadIterator $tokens, &$pNodeId) |
327
|
|
|
{ |
328
|
|
|
$tokens->next(); |
329
|
|
|
$rule = $this->choice($tokens, $pNodeId); |
330
|
|
|
|
331
|
|
|
if ($rule === null) { |
332
|
|
|
return null; |
333
|
|
|
} |
334
|
|
|
|
335
|
|
|
if ($tokens->current()->getName() !== Parser::T_GROUP_CLOSE) { |
336
|
|
|
return null; |
337
|
|
|
} |
338
|
|
|
|
339
|
|
|
$tokens->next(); |
340
|
|
|
|
341
|
|
|
return $rule; |
342
|
|
|
} |
343
|
|
|
|
344
|
|
|
/** |
345
|
|
|
* @param LookaheadIterator $tokens |
346
|
|
|
* @param bool $kept |
347
|
|
|
* @return int|string|null |
348
|
|
|
*/ |
349
|
|
|
protected function token(LookaheadIterator $tokens, bool $kept = true) |
350
|
|
|
{ |
351
|
|
|
$tokenName = $tokens->current()->getValue(1); |
352
|
|
|
|
353
|
|
|
$name = $this->transitionalRuleCounter++; |
354
|
|
|
|
355
|
|
|
$this->parsedRules[$name] = new Terminal($name, $tokenName, $kept); |
356
|
|
|
$tokens->next(); |
357
|
|
|
|
358
|
|
|
return $name; |
359
|
|
|
} |
360
|
|
|
|
361
|
|
|
/** |
362
|
|
|
* @param LookaheadIterator $tokens |
363
|
|
|
* @return int|string |
364
|
|
|
* @throws GrammarException |
365
|
|
|
*/ |
366
|
|
|
protected function invoke(LookaheadIterator $tokens) |
367
|
|
|
{ |
368
|
|
|
$tokenName = $tokens->current()->getValue(1); |
369
|
|
|
|
370
|
|
|
if (! \array_key_exists($tokenName, $this->rules)) { |
371
|
|
|
$error = \vsprintf('Cannot call rule %s() in rule %s because it does not exist.', [ |
372
|
|
|
$tokenName, |
373
|
|
|
$this->ruleName, |
374
|
|
|
]); |
375
|
|
|
|
376
|
|
|
throw new GrammarException($error, 5); |
377
|
|
|
} |
378
|
|
|
|
379
|
|
|
if ($tokens->getNext()->getName() === Eoi::T_NAME) { |
380
|
|
|
$name = $this->transitionalRuleCounter++; |
381
|
|
|
$this->parsedRules[$name] = new Concatenation($name, [$tokenName]); |
382
|
|
|
} else { |
383
|
|
|
$name = $tokenName; |
384
|
|
|
} |
385
|
|
|
|
386
|
|
|
$tokens->next(); |
387
|
|
|
|
388
|
|
|
return $name; |
389
|
|
|
} |
390
|
|
|
} |
391
|
|
|
|
This error can happen if you refactor code and forget to move the variable initialization.
Let’s take a look at a simple example:
The above code is perfectly fine. Now imagine that we re-order the statements:
In that case,
$x
would be read before it is initialized. This was a very basic example, however the principle is the same for the found issue.