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1 # -*- coding: utf-8 -*- | |
2 """ | |
3 jinja2.lexer | |
4 ~~~~~~~~~~~~ | |
5 | |
6 This module implements a Jinja / Python combination lexer. The | |
7 `Lexer` class provided by this module is used to do some preprocessing | |
8 for Jinja. | |
9 | |
10 On the one hand it filters out invalid operators like the bitshift | |
11 operators we don't allow in templates. On the other hand it separates | |
12 template code and python code in expressions. | |
13 | |
14 :copyright: (c) 2010 by the Jinja Team. | |
15 :license: BSD, see LICENSE for more details. | |
16 """ | |
17 import re | |
18 | |
19 from operator import itemgetter | |
20 from collections import deque | |
21 from jinja2.exceptions import TemplateSyntaxError | |
22 from jinja2.utils import LRUCache | |
23 from jinja2._compat import next, iteritems, implements_iterator, text_type, \ | |
24 intern | |
25 | |
26 | |
27 # cache for the lexers. Exists in order to be able to have multiple | |
28 # environments with the same lexer | |
29 _lexer_cache = LRUCache(50) | |
30 | |
31 # static regular expressions | |
32 whitespace_re = re.compile(r'\s+', re.U) | |
33 string_re = re.compile(r"('([^'\\]*(?:\\.[^'\\]*)*)'" | |
34 r'|"([^"\\]*(?:\\.[^"\\]*)*)")', re.S) | |
35 integer_re = re.compile(r'\d+') | |
36 | |
37 # we use the unicode identifier rule if this python version is able | |
38 # to handle unicode identifiers, otherwise the standard ASCII one. | |
39 try: | |
40 compile('föö', '<unknown>', 'eval') | |
41 except SyntaxError: | |
42 name_re = re.compile(r'\b[a-zA-Z_][a-zA-Z0-9_]*\b') | |
43 else: | |
44 from jinja2 import _stringdefs | |
45 name_re = re.compile(r'[%s][%s]*' % (_stringdefs.xid_start, | |
46 _stringdefs.xid_continue)) | |
47 | |
48 float_re = re.compile(r'(?<!\.)\d+\.\d+') | |
49 newline_re = re.compile(r'(\r\n|\r|\n)') | |
50 | |
51 # internal the tokens and keep references to them | |
52 TOKEN_ADD = intern('add') | |
53 TOKEN_ASSIGN = intern('assign') | |
54 TOKEN_COLON = intern('colon') | |
55 TOKEN_COMMA = intern('comma') | |
56 TOKEN_DIV = intern('div') | |
57 TOKEN_DOT = intern('dot') | |
58 TOKEN_EQ = intern('eq') | |
59 TOKEN_FLOORDIV = intern('floordiv') | |
60 TOKEN_GT = intern('gt') | |
61 TOKEN_GTEQ = intern('gteq') | |
62 TOKEN_LBRACE = intern('lbrace') | |
63 TOKEN_LBRACKET = intern('lbracket') | |
64 TOKEN_LPAREN = intern('lparen') | |
65 TOKEN_LT = intern('lt') | |
66 TOKEN_LTEQ = intern('lteq') | |
67 TOKEN_MOD = intern('mod') | |
68 TOKEN_MUL = intern('mul') | |
69 TOKEN_NE = intern('ne') | |
70 TOKEN_PIPE = intern('pipe') | |
71 TOKEN_POW = intern('pow') | |
72 TOKEN_RBRACE = intern('rbrace') | |
73 TOKEN_RBRACKET = intern('rbracket') | |
74 TOKEN_RPAREN = intern('rparen') | |
75 TOKEN_SEMICOLON = intern('semicolon') | |
76 TOKEN_SUB = intern('sub') | |
77 TOKEN_TILDE = intern('tilde') | |
78 TOKEN_WHITESPACE = intern('whitespace') | |
79 TOKEN_FLOAT = intern('float') | |
80 TOKEN_INTEGER = intern('integer') | |
81 TOKEN_NAME = intern('name') | |
82 TOKEN_STRING = intern('string') | |
83 TOKEN_OPERATOR = intern('operator') | |
84 TOKEN_BLOCK_BEGIN = intern('block_begin') | |
85 TOKEN_BLOCK_END = intern('block_end') | |
86 TOKEN_VARIABLE_BEGIN = intern('variable_begin') | |
87 TOKEN_VARIABLE_END = intern('variable_end') | |
88 TOKEN_RAW_BEGIN = intern('raw_begin') | |
89 TOKEN_RAW_END = intern('raw_end') | |
90 TOKEN_COMMENT_BEGIN = intern('comment_begin') | |
91 TOKEN_COMMENT_END = intern('comment_end') | |
92 TOKEN_COMMENT = intern('comment') | |
93 TOKEN_LINESTATEMENT_BEGIN = intern('linestatement_begin') | |
94 TOKEN_LINESTATEMENT_END = intern('linestatement_end') | |
95 TOKEN_LINECOMMENT_BEGIN = intern('linecomment_begin') | |
96 TOKEN_LINECOMMENT_END = intern('linecomment_end') | |
97 TOKEN_LINECOMMENT = intern('linecomment') | |
98 TOKEN_DATA = intern('data') | |
99 TOKEN_INITIAL = intern('initial') | |
100 TOKEN_EOF = intern('eof') | |
101 | |
102 # bind operators to token types | |
103 operators = { | |
104 '+': TOKEN_ADD, | |
105 '-': TOKEN_SUB, | |
106 '/': TOKEN_DIV, | |
107 '//': TOKEN_FLOORDIV, | |
108 '*': TOKEN_MUL, | |
109 '%': TOKEN_MOD, | |
110 '**': TOKEN_POW, | |
111 '~': TOKEN_TILDE, | |
112 '[': TOKEN_LBRACKET, | |
113 ']': TOKEN_RBRACKET, | |
114 '(': TOKEN_LPAREN, | |
115 ')': TOKEN_RPAREN, | |
116 '{': TOKEN_LBRACE, | |
117 '}': TOKEN_RBRACE, | |
118 '==': TOKEN_EQ, | |
119 '!=': TOKEN_NE, | |
120 '>': TOKEN_GT, | |
121 '>=': TOKEN_GTEQ, | |
122 '<': TOKEN_LT, | |
123 '<=': TOKEN_LTEQ, | |
124 '=': TOKEN_ASSIGN, | |
125 '.': TOKEN_DOT, | |
126 ':': TOKEN_COLON, | |
127 '|': TOKEN_PIPE, | |
128 ',': TOKEN_COMMA, | |
129 ';': TOKEN_SEMICOLON | |
130 } | |
131 | |
132 reverse_operators = dict([(v, k) for k, v in iteritems(operators)]) | |
133 assert len(operators) == len(reverse_operators), 'operators dropped' | |
134 operator_re = re.compile('(%s)' % '|'.join(re.escape(x) for x in | |
135 sorted(operators, key=lambda x: -len(x)))) | |
136 | |
137 ignored_tokens = frozenset([TOKEN_COMMENT_BEGIN, TOKEN_COMMENT, | |
138 TOKEN_COMMENT_END, TOKEN_WHITESPACE, | |
139 TOKEN_WHITESPACE, TOKEN_LINECOMMENT_BEGIN, | |
140 TOKEN_LINECOMMENT_END, TOKEN_LINECOMMENT]) | |
141 ignore_if_empty = frozenset([TOKEN_WHITESPACE, TOKEN_DATA, | |
142 TOKEN_COMMENT, TOKEN_LINECOMMENT]) | |
143 | |
144 | |
145 def _describe_token_type(token_type): | |
146 if token_type in reverse_operators: | |
147 return reverse_operators[token_type] | |
148 return { | |
149 TOKEN_COMMENT_BEGIN: 'begin of comment', | |
150 TOKEN_COMMENT_END: 'end of comment', | |
151 TOKEN_COMMENT: 'comment', | |
152 TOKEN_LINECOMMENT: 'comment', | |
153 TOKEN_BLOCK_BEGIN: 'begin of statement block', | |
154 TOKEN_BLOCK_END: 'end of statement block', | |
155 TOKEN_VARIABLE_BEGIN: 'begin of print statement', | |
156 TOKEN_VARIABLE_END: 'end of print statement', | |
157 TOKEN_LINESTATEMENT_BEGIN: 'begin of line statement', | |
158 TOKEN_LINESTATEMENT_END: 'end of line statement', | |
159 TOKEN_DATA: 'template data / text', | |
160 TOKEN_EOF: 'end of template' | |
161 }.get(token_type, token_type) | |
162 | |
163 | |
164 def describe_token(token): | |
165 """Returns a description of the token.""" | |
166 if token.type == 'name': | |
167 return token.value | |
168 return _describe_token_type(token.type) | |
169 | |
170 | |
171 def describe_token_expr(expr): | |
172 """Like `describe_token` but for token expressions.""" | |
173 if ':' in expr: | |
174 type, value = expr.split(':', 1) | |
175 if type == 'name': | |
176 return value | |
177 else: | |
178 type = expr | |
179 return _describe_token_type(type) | |
180 | |
181 | |
182 def count_newlines(value): | |
183 """Count the number of newline characters in the string. This is | |
184 useful for extensions that filter a stream. | |
185 """ | |
186 return len(newline_re.findall(value)) | |
187 | |
188 | |
189 def compile_rules(environment): | |
190 """Compiles all the rules from the environment into a list of rules.""" | |
191 e = re.escape | |
192 rules = [ | |
193 (len(environment.comment_start_string), 'comment', | |
194 e(environment.comment_start_string)), | |
195 (len(environment.block_start_string), 'block', | |
196 e(environment.block_start_string)), | |
197 (len(environment.variable_start_string), 'variable', | |
198 e(environment.variable_start_string)) | |
199 ] | |
200 | |
201 if environment.line_statement_prefix is not None: | |
202 rules.append((len(environment.line_statement_prefix), 'linestatement', | |
203 r'^[ \t\v]*' + e(environment.line_statement_prefix))) | |
204 if environment.line_comment_prefix is not None: | |
205 rules.append((len(environment.line_comment_prefix), 'linecomment', | |
206 r'(?:^|(?<=\S))[^\S\r\n]*' + | |
207 e(environment.line_comment_prefix))) | |
208 | |
209 return [x[1:] for x in sorted(rules, reverse=True)] | |
210 | |
211 | |
212 class Failure(object): | |
213 """Class that raises a `TemplateSyntaxError` if called. | |
214 Used by the `Lexer` to specify known errors. | |
215 """ | |
216 | |
217 def __init__(self, message, cls=TemplateSyntaxError): | |
218 self.message = message | |
219 self.error_class = cls | |
220 | |
221 def __call__(self, lineno, filename): | |
222 raise self.error_class(self.message, lineno, filename) | |
223 | |
224 | |
225 class Token(tuple): | |
226 """Token class.""" | |
227 __slots__ = () | |
228 lineno, type, value = (property(itemgetter(x)) for x in range(3)) | |
229 | |
230 def __new__(cls, lineno, type, value): | |
231 return tuple.__new__(cls, (lineno, intern(str(type)), value)) | |
232 | |
233 def __str__(self): | |
234 if self.type in reverse_operators: | |
235 return reverse_operators[self.type] | |
236 elif self.type == 'name': | |
237 return self.value | |
238 return self.type | |
239 | |
240 def test(self, expr): | |
241 """Test a token against a token expression. This can either be a | |
242 token type or ``'token_type:token_value'``. This can only test | |
243 against string values and types. | |
244 """ | |
245 # here we do a regular string equality check as test_any is usually | |
246 # passed an iterable of not interned strings. | |
247 if self.type == expr: | |
248 return True | |
249 elif ':' in expr: | |
250 return expr.split(':', 1) == [self.type, self.value] | |
251 return False | |
252 | |
253 def test_any(self, *iterable): | |
254 """Test against multiple token expressions.""" | |
255 for expr in iterable: | |
256 if self.test(expr): | |
257 return True | |
258 return False | |
259 | |
260 def __repr__(self): | |
261 return 'Token(%r, %r, %r)' % ( | |
262 self.lineno, | |
263 self.type, | |
264 self.value | |
265 ) | |
266 | |
267 | |
268 @implements_iterator | |
269 class TokenStreamIterator(object): | |
270 """The iterator for tokenstreams. Iterate over the stream | |
271 until the eof token is reached. | |
272 """ | |
273 | |
274 def __init__(self, stream): | |
275 self.stream = stream | |
276 | |
277 def __iter__(self): | |
278 return self | |
279 | |
280 def __next__(self): | |
281 token = self.stream.current | |
282 if token.type is TOKEN_EOF: | |
283 self.stream.close() | |
284 raise StopIteration() | |
285 next(self.stream) | |
286 return token | |
287 | |
288 | |
289 @implements_iterator | |
290 class TokenStream(object): | |
291 """A token stream is an iterable that yields :class:`Token`\s. The | |
292 parser however does not iterate over it but calls :meth:`next` to go | |
293 one token ahead. The current active token is stored as :attr:`current`. | |
294 """ | |
295 | |
296 def __init__(self, generator, name, filename): | |
297 self._iter = iter(generator) | |
298 self._pushed = deque() | |
299 self.name = name | |
300 self.filename = filename | |
301 self.closed = False | |
302 self.current = Token(1, TOKEN_INITIAL, '') | |
303 next(self) | |
304 | |
305 def __iter__(self): | |
306 return TokenStreamIterator(self) | |
307 | |
308 def __bool__(self): | |
309 return bool(self._pushed) or self.current.type is not TOKEN_EOF | |
310 __nonzero__ = __bool__ # py2 | |
311 | |
312 eos = property(lambda x: not x, doc="Are we at the end of the stream?") | |
313 | |
314 def push(self, token): | |
315 """Push a token back to the stream.""" | |
316 self._pushed.append(token) | |
317 | |
318 def look(self): | |
319 """Look at the next token.""" | |
320 old_token = next(self) | |
321 result = self.current | |
322 self.push(result) | |
323 self.current = old_token | |
324 return result | |
325 | |
326 def skip(self, n=1): | |
327 """Got n tokens ahead.""" | |
328 for x in range(n): | |
329 next(self) | |
330 | |
331 def next_if(self, expr): | |
332 """Perform the token test and return the token if it matched. | |
333 Otherwise the return value is `None`. | |
334 """ | |
335 if self.current.test(expr): | |
336 return next(self) | |
337 | |
338 def skip_if(self, expr): | |
339 """Like :meth:`next_if` but only returns `True` or `False`.""" | |
340 return self.next_if(expr) is not None | |
341 | |
342 def __next__(self): | |
343 """Go one token ahead and return the old one""" | |
344 rv = self.current | |
345 if self._pushed: | |
346 self.current = self._pushed.popleft() | |
347 elif self.current.type is not TOKEN_EOF: | |
348 try: | |
349 self.current = next(self._iter) | |
350 except StopIteration: | |
351 self.close() | |
352 return rv | |
353 | |
354 def close(self): | |
355 """Close the stream.""" | |
356 self.current = Token(self.current.lineno, TOKEN_EOF, '') | |
357 self._iter = None | |
358 self.closed = True | |
359 | |
360 def expect(self, expr): | |
361 """Expect a given token type and return it. This accepts the same | |
362 argument as :meth:`jinja2.lexer.Token.test`. | |
363 """ | |
364 if not self.current.test(expr): | |
365 expr = describe_token_expr(expr) | |
366 if self.current.type is TOKEN_EOF: | |
367 raise TemplateSyntaxError('unexpected end of template, ' | |
368 'expected %r.' % expr, | |
369 self.current.lineno, | |
370 self.name, self.filename) | |
371 raise TemplateSyntaxError("expected token %r, got %r" % | |
372 (expr, describe_token(self.current)), | |
373 self.current.lineno, | |
374 self.name, self.filename) | |
375 try: | |
376 return self.current | |
377 finally: | |
378 next(self) | |
379 | |
380 | |
381 def get_lexer(environment): | |
382 """Return a lexer which is probably cached.""" | |
383 key = (environment.block_start_string, | |
384 environment.block_end_string, | |
385 environment.variable_start_string, | |
386 environment.variable_end_string, | |
387 environment.comment_start_string, | |
388 environment.comment_end_string, | |
389 environment.line_statement_prefix, | |
390 environment.line_comment_prefix, | |
391 environment.trim_blocks, | |
392 environment.lstrip_blocks, | |
393 environment.newline_sequence, | |
394 environment.keep_trailing_newline) | |
395 lexer = _lexer_cache.get(key) | |
396 if lexer is None: | |
397 lexer = Lexer(environment) | |
398 _lexer_cache[key] = lexer | |
399 return lexer | |
400 | |
401 | |
402 class Lexer(object): | |
403 """Class that implements a lexer for a given environment. Automatically | |
404 created by the environment class, usually you don't have to do that. | |
405 | |
406 Note that the lexer is not automatically bound to an environment. | |
407 Multiple environments can share the same lexer. | |
408 """ | |
409 | |
410 def __init__(self, environment): | |
411 # shortcuts | |
412 c = lambda x: re.compile(x, re.M | re.S) | |
413 e = re.escape | |
414 | |
415 # lexing rules for tags | |
416 tag_rules = [ | |
417 (whitespace_re, TOKEN_WHITESPACE, None), | |
418 (float_re, TOKEN_FLOAT, None), | |
419 (integer_re, TOKEN_INTEGER, None), | |
420 (name_re, TOKEN_NAME, None), | |
421 (string_re, TOKEN_STRING, None), | |
422 (operator_re, TOKEN_OPERATOR, None) | |
423 ] | |
424 | |
425 # assemble the root lexing rule. because "|" is ungreedy | |
426 # we have to sort by length so that the lexer continues working | |
427 # as expected when we have parsing rules like <% for block and | |
428 # <%= for variables. (if someone wants asp like syntax) | |
429 # variables are just part of the rules if variable processing | |
430 # is required. | |
431 root_tag_rules = compile_rules(environment) | |
432 | |
433 # block suffix if trimming is enabled | |
434 block_suffix_re = environment.trim_blocks and '\\n?' or '' | |
435 | |
436 # strip leading spaces if lstrip_blocks is enabled | |
437 prefix_re = {} | |
438 if environment.lstrip_blocks: | |
439 # use '{%+' to manually disable lstrip_blocks behavior | |
440 no_lstrip_re = e('+') | |
441 # detect overlap between block and variable or comment strings | |
442 block_diff = c(r'^%s(.*)' % e(environment.block_start_string)) | |
443 # make sure we don't mistake a block for a variable or a comment | |
444 m = block_diff.match(environment.comment_start_string) | |
445 no_lstrip_re += m and r'|%s' % e(m.group(1)) or '' | |
446 m = block_diff.match(environment.variable_start_string) | |
447 no_lstrip_re += m and r'|%s' % e(m.group(1)) or '' | |
448 | |
449 # detect overlap between comment and variable strings | |
450 comment_diff = c(r'^%s(.*)' % e(environment.comment_start_string)) | |
451 m = comment_diff.match(environment.variable_start_string) | |
452 no_variable_re = m and r'(?!%s)' % e(m.group(1)) or '' | |
453 | |
454 lstrip_re = r'^[ \t]*' | |
455 block_prefix_re = r'%s%s(?!%s)|%s\+?' % ( | |
456 lstrip_re, | |
457 e(environment.block_start_string), | |
458 no_lstrip_re, | |
459 e(environment.block_start_string), | |
460 ) | |
461 comment_prefix_re = r'%s%s%s|%s\+?' % ( | |
462 lstrip_re, | |
463 e(environment.comment_start_string), | |
464 no_variable_re, | |
465 e(environment.comment_start_string), | |
466 ) | |
467 prefix_re['block'] = block_prefix_re | |
468 prefix_re['comment'] = comment_prefix_re | |
469 else: | |
470 block_prefix_re = '%s' % e(environment.block_start_string) | |
471 | |
472 self.newline_sequence = environment.newline_sequence | |
473 self.keep_trailing_newline = environment.keep_trailing_newline | |
474 | |
475 # global lexing rules | |
476 self.rules = { | |
477 'root': [ | |
478 # directives | |
479 (c('(.*?)(?:%s)' % '|'.join( | |
480 [r'(?P<raw_begin>(?:\s*%s\-|%s)\s*raw\s*(?:\-%s\s*|%s))' % ( | |
481 e(environment.block_start_string), | |
482 block_prefix_re, | |
483 e(environment.block_end_string), | |
484 e(environment.block_end_string) | |
485 )] + [ | |
486 r'(?P<%s_begin>\s*%s\-|%s)' % (n, r, prefix_re.get(n,r)) | |
487 for n, r in root_tag_rules | |
488 ])), (TOKEN_DATA, '#bygroup'), '#bygroup'), | |
489 # data | |
490 (c('.+'), TOKEN_DATA, None) | |
491 ], | |
492 # comments | |
493 TOKEN_COMMENT_BEGIN: [ | |
494 (c(r'(.*?)((?:\-%s\s*|%s)%s)' % ( | |
495 e(environment.comment_end_string), | |
496 e(environment.comment_end_string), | |
497 block_suffix_re | |
498 )), (TOKEN_COMMENT, TOKEN_COMMENT_END), '#pop'), | |
499 (c('(.)'), (Failure('Missing end of comment tag'),), None) | |
500 ], | |
501 # blocks | |
502 TOKEN_BLOCK_BEGIN: [ | |
503 (c('(?:\-%s\s*|%s)%s' % ( | |
504 e(environment.block_end_string), | |
505 e(environment.block_end_string), | |
506 block_suffix_re | |
507 )), TOKEN_BLOCK_END, '#pop'), | |
508 ] + tag_rules, | |
509 # variables | |
510 TOKEN_VARIABLE_BEGIN: [ | |
511 (c('\-%s\s*|%s' % ( | |
512 e(environment.variable_end_string), | |
513 e(environment.variable_end_string) | |
514 )), TOKEN_VARIABLE_END, '#pop') | |
515 ] + tag_rules, | |
516 # raw block | |
517 TOKEN_RAW_BEGIN: [ | |
518 (c('(.*?)((?:\s*%s\-|%s)\s*endraw\s*(?:\-%s\s*|%s%s))' % ( | |
519 e(environment.block_start_string), | |
520 block_prefix_re, | |
521 e(environment.block_end_string), | |
522 e(environment.block_end_string), | |
523 block_suffix_re | |
524 )), (TOKEN_DATA, TOKEN_RAW_END), '#pop'), | |
525 (c('(.)'), (Failure('Missing end of raw directive'),), None) | |
526 ], | |
527 # line statements | |
528 TOKEN_LINESTATEMENT_BEGIN: [ | |
529 (c(r'\s*(\n|$)'), TOKEN_LINESTATEMENT_END, '#pop') | |
530 ] + tag_rules, | |
531 # line comments | |
532 TOKEN_LINECOMMENT_BEGIN: [ | |
533 (c(r'(.*?)()(?=\n|$)'), (TOKEN_LINECOMMENT, | |
534 TOKEN_LINECOMMENT_END), '#pop') | |
535 ] | |
536 } | |
537 | |
538 def _normalize_newlines(self, value): | |
539 """Called for strings and template data to normalize it to unicode.""" | |
540 return newline_re.sub(self.newline_sequence, value) | |
541 | |
542 def tokenize(self, source, name=None, filename=None, state=None): | |
543 """Calls tokeniter + tokenize and wraps it in a token stream. | |
544 """ | |
545 stream = self.tokeniter(source, name, filename, state) | |
546 return TokenStream(self.wrap(stream, name, filename), name, filename) | |
547 | |
548 def wrap(self, stream, name=None, filename=None): | |
549 """This is called with the stream as returned by `tokenize` and wraps | |
550 every token in a :class:`Token` and converts the value. | |
551 """ | |
552 for lineno, token, value in stream: | |
553 if token in ignored_tokens: | |
554 continue | |
555 elif token == 'linestatement_begin': | |
556 token = 'block_begin' | |
557 elif token == 'linestatement_end': | |
558 token = 'block_end' | |
559 # we are not interested in those tokens in the parser | |
560 elif token in ('raw_begin', 'raw_end'): | |
561 continue | |
562 elif token == 'data': | |
563 value = self._normalize_newlines(value) | |
564 elif token == 'keyword': | |
565 token = value | |
566 elif token == 'name': | |
567 value = str(value) | |
568 elif token == 'string': | |
569 # try to unescape string | |
570 try: | |
571 value = self._normalize_newlines(value[1:-1]) \ | |
572 .encode('ascii', 'backslashreplace') \ | |
573 .decode('unicode-escape') | |
574 except Exception as e: | |
575 msg = str(e).split(':')[-1].strip() | |
576 raise TemplateSyntaxError(msg, lineno, name, filename) | |
577 # if we can express it as bytestring (ascii only) | |
578 # we do that for support of semi broken APIs | |
579 # as datetime.datetime.strftime. On python 3 this | |
580 # call becomes a noop thanks to 2to3 | |
581 try: | |
582 value = str(value) | |
583 except UnicodeError: | |
584 pass | |
585 elif token == 'integer': | |
586 value = int(value) | |
587 elif token == 'float': | |
588 value = float(value) | |
589 elif token == 'operator': | |
590 token = operators[value] | |
591 yield Token(lineno, token, value) | |
592 | |
593 def tokeniter(self, source, name, filename=None, state=None): | |
594 """This method tokenizes the text and returns the tokens in a | |
595 generator. Use this method if you just want to tokenize a template. | |
596 """ | |
597 source = text_type(source) | |
598 lines = source.splitlines() | |
599 if self.keep_trailing_newline and source: | |
600 for newline in ('\r\n', '\r', '\n'): | |
601 if source.endswith(newline): | |
602 lines.append('') | |
603 break | |
604 source = '\n'.join(lines) | |
605 pos = 0 | |
606 lineno = 1 | |
607 stack = ['root'] | |
608 if state is not None and state != 'root': | |
609 assert state in ('variable', 'block'), 'invalid state' | |
610 stack.append(state + '_begin') | |
611 else: | |
612 state = 'root' | |
613 statetokens = self.rules[stack[-1]] | |
614 source_length = len(source) | |
615 | |
616 balancing_stack = [] | |
617 | |
618 while 1: | |
619 # tokenizer loop | |
620 for regex, tokens, new_state in statetokens: | |
621 m = regex.match(source, pos) | |
622 # if no match we try again with the next rule | |
623 if m is None: | |
624 continue | |
625 | |
626 # we only match blocks and variables if braces / parentheses | |
627 # are balanced. continue parsing with the lower rule which | |
628 # is the operator rule. do this only if the end tags look | |
629 # like operators | |
630 if balancing_stack and \ | |
631 tokens in ('variable_end', 'block_end', | |
632 'linestatement_end'): | |
633 continue | |
634 | |
635 # tuples support more options | |
636 if isinstance(tokens, tuple): | |
637 for idx, token in enumerate(tokens): | |
638 # failure group | |
639 if token.__class__ is Failure: | |
640 raise token(lineno, filename) | |
641 # bygroup is a bit more complex, in that case we | |
642 # yield for the current token the first named | |
643 # group that matched | |
644 elif token == '#bygroup': | |
645 for key, value in iteritems(m.groupdict()): | |
646 if value is not None: | |
647 yield lineno, key, value | |
648 lineno += value.count('\n') | |
649 break | |
650 else: | |
651 raise RuntimeError('%r wanted to resolve ' | |
652 'the token dynamically' | |
653 ' but no group matched' | |
654 % regex) | |
655 # normal group | |
656 else: | |
657 data = m.group(idx + 1) | |
658 if data or token not in ignore_if_empty: | |
659 yield lineno, token, data | |
660 lineno += data.count('\n') | |
661 | |
662 # strings as token just are yielded as it. | |
663 else: | |
664 data = m.group() | |
665 # update brace/parentheses balance | |
666 if tokens == 'operator': | |
667 if data == '{': | |
668 balancing_stack.append('}') | |
669 elif data == '(': | |
670 balancing_stack.append(')') | |
671 elif data == '[': | |
672 balancing_stack.append(']') | |
673 elif data in ('}', ')', ']'): | |
674 if not balancing_stack: | |
675 raise TemplateSyntaxError('unexpected \'%s\'' % | |
676 data, lineno, name, | |
677 filename) | |
678 expected_op = balancing_stack.pop() | |
679 if expected_op != data: | |
680 raise TemplateSyntaxError('unexpected \'%s\', ' | |
681 'expected \'%s\'' % | |
682 (data, expected_op), | |
683 lineno, name, | |
684 filename) | |
685 # yield items | |
686 if data or tokens not in ignore_if_empty: | |
687 yield lineno, tokens, data | |
688 lineno += data.count('\n') | |
689 | |
690 # fetch new position into new variable so that we can check | |
691 # if there is a internal parsing error which would result | |
692 # in an infinite loop | |
693 pos2 = m.end() | |
694 | |
695 # handle state changes | |
696 if new_state is not None: | |
697 # remove the uppermost state | |
698 if new_state == '#pop': | |
699 stack.pop() | |
700 # resolve the new state by group checking | |
701 elif new_state == '#bygroup': | |
702 for key, value in iteritems(m.groupdict()): | |
703 if value is not None: | |
704 stack.append(key) | |
705 break | |
706 else: | |
707 raise RuntimeError('%r wanted to resolve the ' | |
708 'new state dynamically but' | |
709 ' no group matched' % | |
710 regex) | |
711 # direct state name given | |
712 else: | |
713 stack.append(new_state) | |
714 statetokens = self.rules[stack[-1]] | |
715 # we are still at the same position and no stack change. | |
716 # this means a loop without break condition, avoid that and | |
717 # raise error | |
718 elif pos2 == pos: | |
719 raise RuntimeError('%r yielded empty string without ' | |
720 'stack change' % regex) | |
721 # publish new function and start again | |
722 pos = pos2 | |
723 break | |
724 # if loop terminated without break we haven't found a single match | |
725 # either we are at the end of the file or we have a problem | |
726 else: | |
727 # end of text | |
728 if pos >= source_length: | |
729 return | |
730 # something went wrong | |
731 raise TemplateSyntaxError('unexpected char %r at %d' % | |
732 (source[pos], pos), lineno, | |
733 name, filename) | |
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