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
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
//! Parsers recognizing bytes streams, streaming version

use crate::error::ErrorKind;
use crate::error::ParseError;
use crate::internal::{Err, IResult, Needed, Parser};
use crate::lib::std::ops::RangeFrom;
use crate::lib::std::result::Result::*;
use crate::traits::{
  Compare, CompareResult, FindSubstring, FindToken, InputIter, InputLength, InputTake,
  InputTakeAtPosition, Slice, ToUsize,
};

/// Recognizes a pattern.
///
/// The input data will be compared to the tag combinator's argument and will return the part of
/// the input that matches the argument.
/// # Example
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::bytes::streaming::tag;
///
/// fn parser(s: &str) -> IResult<&str, &str> {
///   tag("Hello")(s)
/// }
///
/// assert_eq!(parser("Hello, World!"), Ok((", World!", "Hello")));
/// assert_eq!(parser("Something"), Err(Err::Error(Error::new("Something", ErrorKind::Tag))));
/// assert_eq!(parser("S"), Err(Err::Error(Error::new("S", ErrorKind::Tag))));
/// assert_eq!(parser("H"), Err(Err::Incomplete(Needed::new(4))));
/// ```
pub fn tag<T, Input, Error: ParseError<Input>>(
  tag: T,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTake + InputLength + Compare<T>,
  T: InputLength + Clone,
{
  move |i: Input| {
    let tag_len = tag.input_len();
    let t = tag.clone();

    let res: IResult<_, _, Error> = match i.compare(t) {
      CompareResult::Ok => Ok(i.take_split(tag_len)),
      CompareResult::Incomplete => Err(Err::Incomplete(Needed::new(tag_len - i.input_len()))),
      CompareResult::Error => {
        let e: ErrorKind = ErrorKind::Tag;
        Err(Err::Error(Error::from_error_kind(i, e)))
      }
    };
    res
  }
}

/// Recognizes a case insensitive pattern.
///
/// The input data will be compared to the tag combinator's argument and will return the part of
/// the input that matches the argument with no regard to case.
/// # Example
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::bytes::streaming::tag_no_case;
///
/// fn parser(s: &str) -> IResult<&str, &str> {
///   tag_no_case("hello")(s)
/// }
///
/// assert_eq!(parser("Hello, World!"), Ok((", World!", "Hello")));
/// assert_eq!(parser("hello, World!"), Ok((", World!", "hello")));
/// assert_eq!(parser("HeLlO, World!"), Ok((", World!", "HeLlO")));
/// assert_eq!(parser("Something"), Err(Err::Error(Error::new("Something", ErrorKind::Tag))));
/// assert_eq!(parser(""), Err(Err::Incomplete(Needed::new(5))));
/// ```
pub fn tag_no_case<T, Input, Error: ParseError<Input>>(
  tag: T,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTake + InputLength + Compare<T>,
  T: InputLength + Clone,
{
  move |i: Input| {
    let tag_len = tag.input_len();
    let t = tag.clone();

    let res: IResult<_, _, Error> = match (i).compare_no_case(t) {
      CompareResult::Ok => Ok(i.take_split(tag_len)),
      CompareResult::Incomplete => Err(Err::Incomplete(Needed::new(tag_len - i.input_len()))),
      CompareResult::Error => {
        let e: ErrorKind = ErrorKind::Tag;
        Err(Err::Error(Error::from_error_kind(i, e)))
      }
    };
    res
  }
}

/// Parse till certain characters are met.
///
/// The parser will return the longest slice till one of the characters of the combinator's argument are met.
///
/// It doesn't consume the matched character.
///
/// It will return a `Err::Incomplete(Needed::new(1))` if the pattern wasn't met.
/// # Example
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::bytes::streaming::is_not;
///
/// fn not_space(s: &str) -> IResult<&str, &str> {
///   is_not(" \t\r\n")(s)
/// }
///
/// assert_eq!(not_space("Hello, World!"), Ok((" World!", "Hello,")));
/// assert_eq!(not_space("Sometimes\t"), Ok(("\t", "Sometimes")));
/// assert_eq!(not_space("Nospace"), Err(Err::Incomplete(Needed::new(1))));
/// assert_eq!(not_space(""), Err(Err::Incomplete(Needed::new(1))));
/// ```
pub fn is_not<T, Input, Error: ParseError<Input>>(
  arr: T,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTakeAtPosition,
  T: FindToken<<Input as InputTakeAtPosition>::Item>,
{
  move |i: Input| {
    let e: ErrorKind = ErrorKind::IsNot;
    i.split_at_position1(|c| arr.find_token(c), e)
  }
}

/// Returns the longest slice of the matches the pattern.
///
/// The parser will return the longest slice consisting of the characters in provided in the
/// combinator's argument.
///
/// # Streaming specific
/// *Streaming version* will return a `Err::Incomplete(Needed::new(1))` if the pattern wasn't met
/// or if the pattern reaches the end of the input.
/// # Example
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::bytes::streaming::is_a;
///
/// fn hex(s: &str) -> IResult<&str, &str> {
///   is_a("1234567890ABCDEF")(s)
/// }
///
/// assert_eq!(hex("123 and voila"), Ok((" and voila", "123")));
/// assert_eq!(hex("DEADBEEF and others"), Ok((" and others", "DEADBEEF")));
/// assert_eq!(hex("BADBABEsomething"), Ok(("something", "BADBABE")));
/// assert_eq!(hex("D15EA5E"), Err(Err::Incomplete(Needed::new(1))));
/// assert_eq!(hex(""), Err(Err::Incomplete(Needed::new(1))));
/// ```
pub fn is_a<T, Input, Error: ParseError<Input>>(
  arr: T,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTakeAtPosition,
  T: FindToken<<Input as InputTakeAtPosition>::Item>,
{
  move |i: Input| {
    let e: ErrorKind = ErrorKind::IsA;
    i.split_at_position1(|c| !arr.find_token(c), e)
  }
}

/// Returns the longest input slice (if any) that matches the predicate.
///
/// The parser will return the longest slice that matches the given predicate *(a function that
/// takes the input and returns a bool)*.
///
/// # Streaming Specific
/// *Streaming version* will return a `Err::Incomplete(Needed::new(1))` if the pattern reaches the end of the input.
/// # Example
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::bytes::streaming::take_while;
/// use nom::character::is_alphabetic;
///
/// fn alpha(s: &[u8]) -> IResult<&[u8], &[u8]> {
///   take_while(is_alphabetic)(s)
/// }
///
/// assert_eq!(alpha(b"latin123"), Ok((&b"123"[..], &b"latin"[..])));
/// assert_eq!(alpha(b"12345"), Ok((&b"12345"[..], &b""[..])));
/// assert_eq!(alpha(b"latin"), Err(Err::Incomplete(Needed::new(1))));
/// assert_eq!(alpha(b""), Err(Err::Incomplete(Needed::new(1))));
/// ```
pub fn take_while<F, Input, Error: ParseError<Input>>(
  cond: F,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTakeAtPosition,
  F: Fn(<Input as InputTakeAtPosition>::Item) -> bool,
{
  move |i: Input| i.split_at_position(|c| !cond(c))
}

/// Returns the longest (at least 1) input slice that matches the predicate.
///
/// The parser will return the longest slice that matches the given predicate *(a function that
/// takes the input and returns a bool)*.
///
/// It will return an `Err(Err::Error((_, ErrorKind::TakeWhile1)))` if the pattern wasn't met.
///
/// # Streaming Specific
/// *Streaming version* will return a `Err::Incomplete(Needed::new(1))` or if the pattern reaches the end of the input.
///
/// # Example
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::bytes::streaming::take_while1;
/// use nom::character::is_alphabetic;
///
/// fn alpha(s: &[u8]) -> IResult<&[u8], &[u8]> {
///   take_while1(is_alphabetic)(s)
/// }
///
/// assert_eq!(alpha(b"latin123"), Ok((&b"123"[..], &b"latin"[..])));
/// assert_eq!(alpha(b"latin"), Err(Err::Incomplete(Needed::new(1))));
/// assert_eq!(alpha(b"12345"), Err(Err::Error(Error::new(&b"12345"[..], ErrorKind::TakeWhile1))));
/// ```
pub fn take_while1<F, Input, Error: ParseError<Input>>(
  cond: F,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTakeAtPosition,
  F: Fn(<Input as InputTakeAtPosition>::Item) -> bool,
{
  move |i: Input| {
    let e: ErrorKind = ErrorKind::TakeWhile1;
    i.split_at_position1(|c| !cond(c), e)
  }
}

/// Returns the longest (m <= len <= n) input slice  that matches the predicate.
///
/// The parser will return the longest slice that matches the given predicate *(a function that
/// takes the input and returns a bool)*.
///
/// It will return an `Err::Error((_, ErrorKind::TakeWhileMN))` if the pattern wasn't met.
/// # Streaming Specific
/// *Streaming version* will return a `Err::Incomplete(Needed::new(1))`  if the pattern reaches the end of the input or is too short.
///
/// # Example
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::bytes::streaming::take_while_m_n;
/// use nom::character::is_alphabetic;
///
/// fn short_alpha(s: &[u8]) -> IResult<&[u8], &[u8]> {
///   take_while_m_n(3, 6, is_alphabetic)(s)
/// }
///
/// assert_eq!(short_alpha(b"latin123"), Ok((&b"123"[..], &b"latin"[..])));
/// assert_eq!(short_alpha(b"lengthy"), Ok((&b"y"[..], &b"length"[..])));
/// assert_eq!(short_alpha(b"latin"), Err(Err::Incomplete(Needed::new(1))));
/// assert_eq!(short_alpha(b"ed"), Err(Err::Incomplete(Needed::new(1))));
/// assert_eq!(short_alpha(b"12345"), Err(Err::Error(Error::new(&b"12345"[..], ErrorKind::TakeWhileMN))));
/// ```
pub fn take_while_m_n<F, Input, Error: ParseError<Input>>(
  m: usize,
  n: usize,
  cond: F,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTake + InputIter + InputLength,
  F: Fn(<Input as InputIter>::Item) -> bool,
{
  move |i: Input| {
    let input = i;

    match input.position(|c| !cond(c)) {
      Some(idx) => {
        if idx >= m {
          if idx <= n {
            let res: IResult<_, _, Error> = if let Ok(index) = input.slice_index(idx) {
              Ok(input.take_split(index))
            } else {
              Err(Err::Error(Error::from_error_kind(
                input,
                ErrorKind::TakeWhileMN,
              )))
            };
            res
          } else {
            let res: IResult<_, _, Error> = if let Ok(index) = input.slice_index(n) {
              Ok(input.take_split(index))
            } else {
              Err(Err::Error(Error::from_error_kind(
                input,
                ErrorKind::TakeWhileMN,
              )))
            };
            res
          }
        } else {
          let e = ErrorKind::TakeWhileMN;
          Err(Err::Error(Error::from_error_kind(input, e)))
        }
      }
      None => {
        let len = input.input_len();
        if len >= n {
          match input.slice_index(n) {
            Ok(index) => Ok(input.take_split(index)),
            Err(_needed) => Err(Err::Error(Error::from_error_kind(
              input,
              ErrorKind::TakeWhileMN,
            ))),
          }
        } else {
          let needed = if m > len { m - len } else { 1 };
          Err(Err::Incomplete(Needed::new(needed)))
        }
      }
    }
  }
}

/// Returns the longest input slice (if any) till a predicate is met.
///
/// The parser will return the longest slice till the given predicate *(a function that
/// takes the input and returns a bool)*.
///
/// # Streaming Specific
/// *Streaming version* will return a `Err::Incomplete(Needed::new(1))` if the match reaches the
/// end of input or if there was not match.
///
/// # Example
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::bytes::streaming::take_till;
///
/// fn till_colon(s: &str) -> IResult<&str, &str> {
///   take_till(|c| c == ':')(s)
/// }
///
/// assert_eq!(till_colon("latin:123"), Ok((":123", "latin")));
/// assert_eq!(till_colon(":empty matched"), Ok((":empty matched", ""))); //allowed
/// assert_eq!(till_colon("12345"), Err(Err::Incomplete(Needed::new(1))));
/// assert_eq!(till_colon(""), Err(Err::Incomplete(Needed::new(1))));
/// ```
pub fn take_till<F, Input, Error: ParseError<Input>>(
  cond: F,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTakeAtPosition,
  F: Fn(<Input as InputTakeAtPosition>::Item) -> bool,
{
  move |i: Input| i.split_at_position(|c| cond(c))
}

/// Returns the longest (at least 1) input slice till a predicate is met.
///
/// The parser will return the longest slice till the given predicate *(a function that
/// takes the input and returns a bool)*.
///
/// # Streaming Specific
/// *Streaming version* will return a `Err::Incomplete(Needed::new(1))` if the match reaches the
/// end of input or if there was not match.
/// # Example
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::bytes::streaming::take_till1;
///
/// fn till_colon(s: &str) -> IResult<&str, &str> {
///   take_till1(|c| c == ':')(s)
/// }
///
/// assert_eq!(till_colon("latin:123"), Ok((":123", "latin")));
/// assert_eq!(till_colon(":empty matched"), Err(Err::Error(Error::new(":empty matched", ErrorKind::TakeTill1))));
/// assert_eq!(till_colon("12345"), Err(Err::Incomplete(Needed::new(1))));
/// assert_eq!(till_colon(""), Err(Err::Incomplete(Needed::new(1))));
/// ```
pub fn take_till1<F, Input, Error: ParseError<Input>>(
  cond: F,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTakeAtPosition,
  F: Fn(<Input as InputTakeAtPosition>::Item) -> bool,
{
  move |i: Input| {
    let e: ErrorKind = ErrorKind::TakeTill1;
    i.split_at_position1(|c| cond(c), e)
  }
}

/// Returns an input slice containing the first N input elements (Input[..N]).
///
/// # Streaming Specific
/// *Streaming version* if the input has less than N elements, `take` will
/// return a `Err::Incomplete(Needed::new(M))` where M is the number of
/// additional bytes the parser would need to succeed.
/// It is well defined for `&[u8]` as the number of elements is the byte size,
/// but for types like `&str`, we cannot know how many bytes correspond for
/// the next few chars, so the result will be `Err::Incomplete(Needed::Unknown)`
///
/// # Example
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::bytes::streaming::take;
///
/// fn take6(s: &str) -> IResult<&str, &str> {
///   take(6usize)(s)
/// }
///
/// assert_eq!(take6("1234567"), Ok(("7", "123456")));
/// assert_eq!(take6("things"), Ok(("", "things")));
/// assert_eq!(take6("short"), Err(Err::Incomplete(Needed::Unknown)));
/// ```
pub fn take<C, Input, Error: ParseError<Input>>(
  count: C,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputIter + InputTake + InputLength,
  C: ToUsize,
{
  let c = count.to_usize();
  move |i: Input| match i.slice_index(c) {
    Err(i) => Err(Err::Incomplete(i)),
    Ok(index) => Ok(i.take_split(index)),
  }
}

/// Returns the input slice up to the first occurrence of the pattern.
///
/// It doesn't consume the pattern.
///
/// # Streaming Specific
/// *Streaming version* will return a `Err::Incomplete(Needed::new(N))` if the input doesn't
/// contain the pattern or if the input is smaller than the pattern.
/// # Example
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::bytes::streaming::take_until;
///
/// fn until_eof(s: &str) -> IResult<&str, &str> {
///   take_until("eof")(s)
/// }
///
/// assert_eq!(until_eof("hello, worldeof"), Ok(("eof", "hello, world")));
/// assert_eq!(until_eof("hello, world"), Err(Err::Incomplete(Needed::Unknown)));
/// assert_eq!(until_eof("hello, worldeo"), Err(Err::Incomplete(Needed::Unknown)));
/// assert_eq!(until_eof("1eof2eof"), Ok(("eof2eof", "1")));
/// ```
pub fn take_until<T, Input, Error: ParseError<Input>>(
  tag: T,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTake + InputLength + FindSubstring<T>,
  T: Clone,
{
  move |i: Input| {
    let t = tag.clone();

    let res: IResult<_, _, Error> = match i.find_substring(t) {
      None => Err(Err::Incomplete(Needed::Unknown)),
      Some(index) => Ok(i.take_split(index)),
    };
    res
  }
}

/// Returns the non empty input slice up to the first occurrence of the pattern.
///
/// It doesn't consume the pattern.
///
/// # Streaming Specific
/// *Streaming version* will return a `Err::Incomplete(Needed::new(N))` if the input doesn't
/// contain the pattern or if the input is smaller than the pattern.
/// # Example
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::bytes::streaming::take_until1;
///
/// fn until_eof(s: &str) -> IResult<&str, &str> {
///   take_until1("eof")(s)
/// }
///
/// assert_eq!(until_eof("hello, worldeof"), Ok(("eof", "hello, world")));
/// assert_eq!(until_eof("hello, world"), Err(Err::Incomplete(Needed::Unknown)));
/// assert_eq!(until_eof("hello, worldeo"), Err(Err::Incomplete(Needed::Unknown)));
/// assert_eq!(until_eof("1eof2eof"), Ok(("eof2eof", "1")));
/// assert_eq!(until_eof("eof"),  Err(Err::Error(Error::new("eof", ErrorKind::TakeUntil))));
/// ```
pub fn take_until1<T, Input, Error: ParseError<Input>>(
  tag: T,
) -> impl Fn(Input) -> IResult<Input, Input, Error>
where
  Input: InputTake + InputLength + FindSubstring<T>,
  T: Clone,
{
  move |i: Input| {
    let t = tag.clone();

    let res: IResult<_, _, Error> = match i.find_substring(t) {
      None => Err(Err::Incomplete(Needed::Unknown)),
      Some(0) => Err(Err::Error(Error::from_error_kind(i, ErrorKind::TakeUntil))),
      Some(index) => Ok(i.take_split(index)),
    };
    res
  }
}

/// Matches a byte string with escaped characters.
///
/// * The first argument matches the normal characters (it must not accept the control character)
/// * The second argument is the control character (like `\` in most languages)
/// * The third argument matches the escaped characters
/// # Example
/// ```
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// # use nom::character::complete::digit1;
/// use nom::bytes::streaming::escaped;
/// use nom::character::streaming::one_of;
///
/// fn esc(s: &str) -> IResult<&str, &str> {
///   escaped(digit1, '\\', one_of("\"n\\"))(s)
/// }
///
/// assert_eq!(esc("123;"), Ok((";", "123")));
/// assert_eq!(esc("12\\\"34;"), Ok((";", "12\\\"34")));
/// ```
///
pub fn escaped<Input, Error, F, G, O1, O2>(
  mut normal: F,
  control_char: char,
  mut escapable: G,
) -> impl FnMut(Input) -> IResult<Input, Input, Error>
where
  Input: Clone
    + crate::traits::Offset
    + InputLength
    + InputTake
    + InputTakeAtPosition
    + Slice<RangeFrom<usize>>
    + InputIter,
  <Input as InputIter>::Item: crate::traits::AsChar,
  F: Parser<Input, O1, Error>,
  G: Parser<Input, O2, Error>,
  Error: ParseError<Input>,
{
  use crate::traits::AsChar;

  move |input: Input| {
    let mut i = input.clone();

    while i.input_len() > 0 {
      let current_len = i.input_len();

      match normal.parse(i.clone()) {
        Ok((i2, _)) => {
          if i2.input_len() == 0 {
            return Err(Err::Incomplete(Needed::Unknown));
          } else if i2.input_len() == current_len {
            let index = input.offset(&i2);
            return Ok(input.take_split(index));
          } else {
            i = i2;
          }
        }
        Err(Err::Error(_)) => {
          // unwrap() should be safe here since index < $i.input_len()
          if i.iter_elements().next().unwrap().as_char() == control_char {
            let next = control_char.len_utf8();
            if next >= i.input_len() {
              return Err(Err::Incomplete(Needed::new(1)));
            } else {
              match escapable.parse(i.slice(next..)) {
                Ok((i2, _)) => {
                  if i2.input_len() == 0 {
                    return Err(Err::Incomplete(Needed::Unknown));
                  } else {
                    i = i2;
                  }
                }
                Err(e) => return Err(e),
              }
            }
          } else {
            let index = input.offset(&i);
            return Ok(input.take_split(index));
          }
        }
        Err(e) => {
          return Err(e);
        }
      }
    }

    Err(Err::Incomplete(Needed::Unknown))
  }
}

/// Matches a byte string with escaped characters.
///
/// * The first argument matches the normal characters (it must not match the control character)
/// * The second argument is the control character (like `\` in most languages)
/// * The third argument matches the escaped characters and transforms them
///
/// As an example, the chain `abc\tdef` could be `abc    def` (it also consumes the control character)
///
/// ```
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// # use std::str::from_utf8;
/// use nom::bytes::streaming::{escaped_transform, tag};
/// use nom::character::streaming::alpha1;
/// use nom::branch::alt;
/// use nom::combinator::value;
///
/// fn parser(input: &str) -> IResult<&str, String> {
///   escaped_transform(
///     alpha1,
///     '\\',
///     alt((
///       value("\\", tag("\\")),
///       value("\"", tag("\"")),
///       value("\n", tag("n")),
///     ))
///   )(input)
/// }
///
/// assert_eq!(parser("ab\\\"cd\""), Ok(("\"", String::from("ab\"cd"))));
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
pub fn escaped_transform<Input, Error, F, G, O1, O2, ExtendItem, Output>(
  mut normal: F,
  control_char: char,
  mut transform: G,
) -> impl FnMut(Input) -> IResult<Input, Output, Error>
where
  Input: Clone
    + crate::traits::Offset
    + InputLength
    + InputTake
    + InputTakeAtPosition
    + Slice<RangeFrom<usize>>
    + InputIter,
  Input: crate::traits::ExtendInto<Item = ExtendItem, Extender = Output>,
  O1: crate::traits::ExtendInto<Item = ExtendItem, Extender = Output>,
  O2: crate::traits::ExtendInto<Item = ExtendItem, Extender = Output>,
  <Input as InputIter>::Item: crate::traits::AsChar,
  F: Parser<Input, O1, Error>,
  G: Parser<Input, O2, Error>,
  Error: ParseError<Input>,
{
  use crate::traits::AsChar;

  move |input: Input| {
    let mut index = 0;
    let mut res = input.new_builder();

    let i = input.clone();

    while index < i.input_len() {
      let current_len = i.input_len();
      let remainder = i.slice(index..);
      match normal.parse(remainder.clone()) {
        Ok((i2, o)) => {
          o.extend_into(&mut res);
          if i2.input_len() == 0 {
            return Err(Err::Incomplete(Needed::Unknown));
          } else if i2.input_len() == current_len {
            return Ok((remainder, res));
          } else {
            index = input.offset(&i2);
          }
        }
        Err(Err::Error(_)) => {
          // unwrap() should be safe here since index < $i.input_len()
          if remainder.iter_elements().next().unwrap().as_char() == control_char {
            let next = index + control_char.len_utf8();
            let input_len = input.input_len();

            if next >= input_len {
              return Err(Err::Incomplete(Needed::Unknown));
            } else {
              match transform.parse(i.slice(next..)) {
                Ok((i2, o)) => {
                  o.extend_into(&mut res);
                  if i2.input_len() == 0 {
                    return Err(Err::Incomplete(Needed::Unknown));
                  } else {
                    index = input.offset(&i2);
                  }
                }
                Err(e) => return Err(e),
              }
            }
          } else {
            return Ok((remainder, res));
          }
        }
        Err(e) => return Err(e),
      }
    }
    Err(Err::Incomplete(Needed::Unknown))
  }
}