OILS / builtin / method_str.py View on Github | oils.pub

622 lines, 374 significant
1"""YSH Str methods"""
2
3from __future__ import print_function
4
5from _devbuild.gen.syntax_asdl import loc_t
6from _devbuild.gen.value_asdl import (value, value_e, value_t, eggex_ops,
7 eggex_ops_t, RegexMatch)
8from core import error
9from core import state
10from core import vm
11from frontend import typed_args
12from mycpp import mops
13from mycpp.mylib import log, tagswitch
14from osh import string_ops
15from ysh import expr_eval
16from ysh import regex_translate
17from ysh import val_ops
18
19import libc
20from libc import REG_NOTBOL
21
22from typing import cast, Dict, List, Optional, Tuple
23
24_ = log
25
26
27def _StrMatchStart(s, p):
28 # type: (str, str) -> Tuple[bool, int, int]
29 """Returns the range of bytes in 's' that match string pattern `p`. the
30 pattern matches if 's' starts with all the characters in 'p'.
31
32 The returned match result is the tuple "(matched, begin, end)". 'matched'
33 is true if the pattern matched. 'begin' and 'end' give the half-open range
34 "[begin, end)" of byte indices from 's' for the match, and are a valid but
35 empty range if 'match' is false.
36
37 Used for shell functions like 'trimStart' when trimming a prefix string.
38 """
39 if s.startswith(p):
40 return (True, 0, len(p))
41 else:
42 return (False, 0, 0)
43
44
45def _StrMatchEnd(s, p):
46 # type: (str, str) -> Tuple[bool, int, int]
47 """Returns a match result for the bytes in 's' that match string pattern
48 `p`. the pattern matches if 's' ends with all the characters in 'p'.
49
50 The returned match result is the tuple "(matched, begin, end)". 'matched'
51 is true if the pattern matched. 'begin' and 'end' give the half-open range
52 "[begin, end)" of byte indices from 's' for the match, and are a valid but
53 empty range if 'match' is false.
54
55 Used for shell functions like 'trimEnd' when trimming a suffix string.
56 """
57 len_s = len(s)
58 if s.endswith(p):
59 return (True, len_s - len(p), len_s)
60 else:
61 return (False, len_s, len_s)
62
63
64def _EggexMatchCommon(s, p, ere, empty_p):
65 # type: (str, value.Eggex, str, int) -> Tuple[bool, int, int]
66 cflags = regex_translate.LibcFlags(p.canonical_flags)
67 eflags = 0
68 indices = libc.regex_search(ere, cflags, s, eflags)
69 if indices is None:
70 return (False, empty_p, empty_p)
71
72 start = indices[0]
73 end = indices[1]
74
75 return (True, start, end)
76
77
78def _EggexMatchStart(s, p):
79 # type: (str, value.Eggex) -> Tuple[bool, int, int]
80 """Returns a match result for the bytes in 's' that match Eggex pattern
81 `p` when constrained to match at the start of the string.
82
83 Any capturing done by the Eggex pattern is ignored.
84
85 The returned match result is the tuple "(matched, begin, end)". 'matched'
86 is true if the pattern matched. 'begin' and 'end' give the half-open range
87 "[begin, end)" of byte indices from 's' for the match, and are a valid but
88 empty range if 'match' is false.
89
90 Used for shell functions like 'trimStart' when trimming with an Eggex
91 pattern.
92 """
93 ere = regex_translate.AsPosixEre(p)
94 if not ere.startswith('^'):
95 ere = '^' + ere
96 return _EggexMatchCommon(s, p, ere, 0)
97
98
99def _EggexMatchEnd(s, p):
100 # type: (str, value.Eggex) -> Tuple[bool, int, int]
101 """Like _EggexMatchStart, but matches against the end of the
102 string.
103 """
104 ere = regex_translate.AsPosixEre(p)
105 if not ere.endswith('$'):
106 ere = ere + '$'
107 return _EggexMatchCommon(s, p, ere, len(s))
108
109
110START = 0b01
111END = 0b10
112
113
114class HasAffix(vm._Callable):
115 """ Implements `startsWith()`, `endsWith()`. """
116
117 def __init__(self, anchor):
118 # type: (int) -> None
119 assert anchor in (START, END), ("Anchor must be START or END")
120 self.anchor = anchor
121
122 def Call(self, rd):
123 # type: (typed_args.Reader) -> value_t
124 """
125 string => startsWith(pattern_str) # => bool
126 string => startsWith(pattern_eggex) # => bool
127 string => endsWith(pattern_str) # => bool
128 string => endsWith(pattern_eggex) # => bool
129 """
130
131 string = rd.PosStr()
132 pattern_val = rd.PosValue()
133 pattern_str = None # type: Optional[str]
134 pattern_eggex = None # type: value.Eggex
135 with tagswitch(pattern_val) as case:
136 if case(value_e.Eggex):
137 pattern_eggex = cast(value.Eggex, pattern_val)
138 elif case(value_e.Str):
139 pattern_str = cast(value.Str, pattern_val).s
140 else:
141 raise error.TypeErr(pattern_val,
142 'expected pattern to be Eggex or Str',
143 rd.LeftParenToken())
144 rd.Done()
145
146 matched = False
147 try:
148 if pattern_str is not None:
149 if self.anchor & START:
150 matched, _, _ = _StrMatchStart(string, pattern_str)
151 else:
152 matched, _, _ = _StrMatchEnd(string, pattern_str)
153 else:
154 assert pattern_eggex is not None
155 if self.anchor & START:
156 matched, _, _ = _EggexMatchStart(string, pattern_eggex)
157 else:
158 matched, _, _ = _EggexMatchEnd(string, pattern_eggex)
159 except error.Strict as e:
160 raise error.Expr(e.msg, e.location)
161
162 return value.Bool(matched)
163
164
165class Trim(vm._Callable):
166 """ Implements `trimStart()`, `trimEnd()`, and `trim()` """
167
168 def __init__(self, anchor):
169 # type: (int) -> None
170 assert anchor in (START, END, START
171 | END), ("Anchor must be START, END, or START|END")
172 self.anchor = anchor
173
174 def Call(self, rd):
175 # type: (typed_args.Reader) -> value_t
176 """
177 string => trimStart() # => Str
178 string => trimEnd() # => Str
179 string => trim() # => Str
180 string => trimStart(pattern_str) # => Str
181 string => trimEnd(pattern_str) # => Str
182 string => trim(pattern_str) # => Str
183 string => trimStart(pattern_eggex) # => Str
184 string => trimEnd(pattern_eggex) # => Str
185 string => trim(pattern_eggex) # => Str
186 """
187
188 string = rd.PosStr()
189 pattern_val = rd.OptionalValue()
190 pattern_str = None # type: Optional[str]
191 pattern_eggex = None # type: value.Eggex
192 if pattern_val:
193 with tagswitch(pattern_val) as case:
194 if case(value_e.Eggex):
195 pattern_eggex = cast(value.Eggex, pattern_val)
196 elif case(value_e.Str):
197 pattern_str = cast(value.Str, pattern_val).s
198 else:
199 raise error.TypeErr(pattern_val,
200 'expected pattern to be Eggex or Str',
201 rd.LeftParenToken())
202 rd.Done()
203
204 start = 0
205 end = len(string)
206 try:
207 if pattern_str is not None:
208 if self.anchor & START:
209 _, _, start = _StrMatchStart(string, pattern_str)
210 if self.anchor & END:
211 _, end, _ = _StrMatchEnd(string, pattern_str)
212 elif pattern_eggex is not None:
213 if self.anchor & START:
214 _, _, start = _EggexMatchStart(string, pattern_eggex)
215 if self.anchor & END:
216 _, end, _ = _EggexMatchEnd(string, pattern_eggex)
217 else:
218 if self.anchor & START:
219 _, start = string_ops.StartsWithWhitespaceByteRange(string)
220 if self.anchor & END:
221 end, _ = string_ops.EndsWithWhitespaceByteRange(string)
222 except error.Strict as e:
223 raise error.Expr(e.msg, e.location)
224
225 res = string[start:end]
226 return value.Str(res)
227
228
229class Upper(vm._Callable):
230
231 def __init__(self):
232 # type: () -> None
233 pass
234
235 def Call(self, rd):
236 # type: (typed_args.Reader) -> value_t
237
238 s = rd.PosStr()
239 rd.Done()
240
241 # TODO: unicode support
242 return value.Str(s.upper())
243
244
245class Lower(vm._Callable):
246
247 def __init__(self):
248 # type: () -> None
249 pass
250
251 def Call(self, rd):
252 # type: (typed_args.Reader) -> value_t
253
254 s = rd.PosStr()
255 rd.Done()
256
257 # TODO: unicode support
258 return value.Str(s.lower())
259
260
261SEARCH = 0
262LEFT_MATCH = 1
263
264
265class SearchMatch(vm._Callable):
266
267 def __init__(self, which_method):
268 # type: (int) -> None
269 self.which_method = which_method
270
271 def Call(self, rd):
272 # type: (typed_args.Reader) -> value_t
273 """
274 s => search(eggex, pos=0)
275 """
276 string = rd.PosStr()
277
278 pattern = rd.PosValue() # Eggex or ERE Str
279 with tagswitch(pattern) as case:
280 if case(value_e.Eggex):
281 eggex_val = cast(value.Eggex, pattern)
282
283 # lazily converts to ERE
284 ere = regex_translate.AsPosixEre(eggex_val)
285 cflags = regex_translate.LibcFlags(eggex_val.canonical_flags)
286 capture = eggex_ops.Yes(
287 eggex_val.convert_funcs, eggex_val.convert_toks,
288 eggex_val.capture_names) # type: eggex_ops_t
289
290 elif case(value_e.Str):
291 ere = cast(value.Str, pattern).s
292 cflags = 0
293 capture = eggex_ops.No
294
295 else:
296 # TODO: add method name to this error
297 raise error.TypeErr(pattern, 'expected Eggex or Str',
298 rd.LeftParenToken())
299
300 # It's called 'pos', not 'start' like Python. Python has 2 kinds of
301 # 'start' in its regex API, which can be confusing.
302 pos = mops.BigTruncate(rd.NamedInt('pos', 0))
303 rd.Done()
304
305 # Make it anchored
306 if self.which_method == LEFT_MATCH:
307 ere = '^(%s)' % ere
308
309 if self.which_method == LEFT_MATCH:
310 eflags = 0 # ^ matches beginning even if pos=5
311 else:
312 eflags = 0 if pos == 0 else REG_NOTBOL # ^ only matches when pos=0
313
314 indices = libc.regex_search(ere, cflags, string, eflags, pos)
315
316 if indices is None:
317 return value.Null
318
319 if self.which_method == LEFT_MATCH:
320 # undo the ^() transformation
321 indices = indices[2:]
322
323 return RegexMatch(string, indices, capture)
324
325
326class Replace(vm._Callable):
327
328 def __init__(self, mem, expr_ev):
329 # type: (state.Mem, expr_eval.ExprEvaluator) -> None
330 self.mem = mem
331 self.expr_ev = expr_ev
332
333 def EvalSubstExpr(self, expr, blame_loc):
334 # type: (value.Expr, loc_t) -> str
335 res = self.expr_ev.EvalExprClosure(expr, blame_loc)
336 if res.tag() == value_e.Str:
337 return cast(value.Str, res).s
338
339 raise error.TypeErr(res, "expected expr to eval to a Str", blame_loc)
340
341 def Call(self, rd):
342 # type: (typed_args.Reader) -> value_t
343 """
344 s => replace(string_val, subst_str, count=-1)
345 s => replace(string_val, subst_expr, count=-1)
346 s => replace(eggex_val, subst_str, count=-1)
347 s => replace(eggex_val, subst_expr, count=-1)
348
349 For count in [0, MAX_INT], there will be no more than count
350 replacements. Any negative count should read as unset, and replace will
351 replace all occurances of the pattern.
352 """
353 string = rd.PosStr()
354
355 string_val = None # type: value.Str
356 eggex_val = None # type: value.Eggex
357 subst_str = None # type: value.Str
358 subst_expr = None # type: value.Expr
359
360 pattern = rd.PosValue()
361 with tagswitch(pattern) as case:
362 if case(value_e.Eggex):
363 # HACK: mycpp will otherwise generate:
364 # value::Eggex* eggex_val ...
365 eggex_val_ = cast(value.Eggex, pattern)
366 eggex_val = eggex_val_
367
368 elif case(value_e.Str):
369 string_val_ = cast(value.Str, pattern)
370 string_val = string_val_
371
372 else:
373 raise error.TypeErr(pattern,
374 'expected pattern to be Eggex or Str',
375 rd.LeftParenToken())
376
377 subst = rd.PosValue()
378 with tagswitch(subst) as case:
379 if case(value_e.Str):
380 subst_str_ = cast(value.Str, subst)
381 subst_str = subst_str_
382
383 elif case(value_e.Expr):
384 subst_expr_ = cast(value.Expr, subst)
385 subst_expr = subst_expr_
386
387 else:
388 raise error.TypeErr(subst,
389 'expected substitution to be Str or Expr',
390 rd.LeftParenToken())
391
392 count = mops.BigTruncate(rd.NamedInt("count", -1))
393 rd.Done()
394
395 if count == 0:
396 return value.Str(string)
397
398 if string_val:
399 if subst_str:
400 s = subst_str.s
401 if subst_expr:
402 # Eval with $0 set to string_val (the matched substring)
403 with state.ctx_Eval(self.mem, string_val.s, None, None):
404 s = self.EvalSubstExpr(subst_expr, rd.LeftParenToken())
405 assert s is not None
406
407 result = string.replace(string_val.s, s, count)
408
409 return value.Str(result)
410
411 if eggex_val:
412 if '\0' in string:
413 raise error.Structured(
414 3, "cannot replace by eggex on a string with NUL bytes",
415 rd.LeftParenToken())
416
417 ere = regex_translate.AsPosixEre(eggex_val)
418 cflags = regex_translate.LibcFlags(eggex_val.canonical_flags)
419
420 # Walk through the string finding all matches of the compiled ere.
421 # Then, collect unmatched substrings and substitutions into the
422 # `parts` list.
423 pos = 0
424 parts = [] # type: List[str]
425 replace_count = 0
426 while pos < len(string):
427 indices = libc.regex_search(ere, cflags, string, 0, pos)
428 if indices is None:
429 break
430
431 # Collect captures
432 arg0 = None # type: Optional[str]
433 argv = [] # type: List[str]
434 named_vars = {} # type: Dict[str, value_t]
435 num_groups = len(indices) / 2
436 for group in xrange(num_groups):
437 start = indices[2 * group]
438 end = indices[2 * group + 1]
439 captured = string[start:end]
440 val = value.Str(captured) # type: value_t
441
442 if len(eggex_val.convert_funcs) and group != 0:
443 convert_func = eggex_val.convert_funcs[group - 1]
444 convert_tok = eggex_val.convert_toks[group - 1]
445
446 if convert_func:
447 val = self.expr_ev.CallConvertFunc(
448 convert_func, val, convert_tok,
449 rd.LeftParenToken())
450
451 # $0, $1, $2 variables are argv values, which must be
452 # strings. Furthermore, they can only be used in string
453 # contexts
454 # eg. "$[1]" != "$1".
455 val_str = val_ops.Stringify(val, rd.LeftParenToken(), '')
456 if group == 0:
457 arg0 = val_str
458 else:
459 argv.append(val_str)
460
461 # $0 cannot be named
462 if group != 0:
463 name = eggex_val.capture_names[group - 2]
464 if name is not None:
465 named_vars[name] = val
466
467 if subst_str:
468 s = subst_str.s
469 if subst_expr:
470 with state.ctx_Eval(self.mem, arg0, argv, named_vars):
471 s = self.EvalSubstExpr(subst_expr, rd.LeftParenToken())
472 assert s is not None
473
474 start = indices[0]
475 end = indices[1]
476 if pos == end:
477 raise error.Structured(
478 3, "eggex should never match the empty string",
479 rd.LeftParenToken())
480
481 parts.append(string[pos:start]) # Unmatched substring
482 parts.append(s) # Replacement
483 pos = end # Move to end of match
484
485 replace_count += 1
486 if count != -1 and replace_count == count:
487 break
488
489 parts.append(string[pos:]) # Remaining unmatched substring
490
491 return value.Str("".join(parts))
492
493 raise AssertionError()
494
495
496class Split(vm._Callable):
497
498 def __init__(self):
499 # type: () -> None
500 pass
501
502 def Call(self, rd):
503 # type: (typed_args.Reader) -> value_t
504 """
505 s.split(string_sep, count=-1)
506 s.split(eggex_sep, count=-1)
507
508 Count behaves like in replace() in that:
509 - `count` < 0 -> ignore
510 - `count` >= 0 -> there will be at most `count` splits
511 """
512 string = rd.PosStr()
513
514 string_sep = None # type: Optional[str]
515 eggex_sep = None # type: value.Eggex
516
517 sep = rd.PosValue()
518 with tagswitch(sep) as case:
519 if case(value_e.Eggex):
520 eggex_sep_ = cast(value.Eggex, sep)
521 eggex_sep = eggex_sep_
522
523 elif case(value_e.Str):
524 string_sep_ = cast(value.Str, sep)
525 string_sep = string_sep_.s
526
527 else:
528 raise error.TypeErr(sep,
529 'expected separator to be Eggex or Str',
530 rd.LeftParenToken())
531
532 count = mops.BigTruncate(rd.NamedInt("count", -1))
533 rd.Done()
534
535 if len(string) == 0:
536 return value.List([])
537
538 if string_sep is not None:
539 if len(string_sep) == 0:
540 raise error.Structured(3, "separator must be non-empty",
541 rd.LeftParenToken())
542
543 cursor = 0
544 chunks = [] # type: List[value_t]
545 length = len(string)
546 while cursor < length and count != 0:
547 next_pos = string.find(string_sep, cursor)
548 if next_pos == -1:
549 break
550
551 chunks.append(value.Str(string[cursor:next_pos]))
552 cursor = next_pos + len(string_sep)
553 count -= 1
554
555 chunks.append(value.Str(string[cursor:]))
556
557 return value.List(chunks)
558
559 if eggex_sep is not None:
560 if '\0' in string:
561 raise error.Structured(
562 3, "cannot split a string with a NUL byte",
563 rd.LeftParenToken())
564
565 regex = regex_translate.AsPosixEre(eggex_sep)
566 cflags = regex_translate.LibcFlags(eggex_sep.canonical_flags)
567
568 cursor = 0
569 chunks = []
570 while cursor < len(string) and count != 0:
571 m = libc.regex_search(regex, cflags, string, 0, cursor)
572 if m is None:
573 break
574
575 start = m[0]
576 end = m[1]
577 if start == end:
578 raise error.Structured(
579 3,
580 "eggex separators should never match the empty string",
581 rd.LeftParenToken())
582
583 chunks.append(value.Str(string[cursor:start]))
584 cursor = end
585
586 count -= 1
587
588 chunks.append(value.Str(string[cursor:]))
589
590 return value.List(chunks)
591
592 raise AssertionError()
593
594
595class Lines(vm._Callable):
596
597 def __init__(self):
598 # type: () -> None
599 pass
600
601 def Call(self, rd):
602 # type: (typed_args.Reader) -> value_t
603 string = rd.PosStr()
604 eol = rd.NamedStr('eol', '\n')
605
606 # Adapted from Str.split() above, except for the handling of the last item
607
608 cursor = 0
609 chunks = [] # type: List[value_t]
610 length = len(string)
611 while cursor < length:
612 next_pos = string.find(eol, cursor)
613 if next_pos == -1:
614 break
615
616 chunks.append(value.Str(string[cursor:next_pos]))
617 cursor = next_pos + len(eol)
618
619 if cursor < length:
620 chunks.append(value.Str(string[cursor:]))
621
622 return value.List(chunks)