      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

    //! Unicode string slices.
    //!
    //! *[See also the `str` primitive type](../../std/primitive.str.html).*
    //!
    //! The `&str` type is one of the two main string types, the other being `String`.
    //! Unlike its `String` counterpart, its contents are borrowed.
    //!
    //! # Basic Usage
    //!
    //! A basic string declaration of `&str` type:
    //!
    //! ```
    //! let hello_world = "Hello, World!";
    //! ```
    //!
    //! Here we have declared a string literal, also known as a string slice.
    //! String literals have a static lifetime, which means the string `hello_world`
    //! is guaranteed to be valid for the duration of the entire program.
    //! We can explicitly specify `hello_world`'s lifetime as well:
    //!
    //! ```
    //! let hello_world: &'static str = "Hello, world!";
    //! ```

    #![stable(feature = "rust1", since = "1.0.0")]

    // Many of the usings in this module are only used in the test configuration.
    // It's cleaner to just turn off the unused_imports warning than to fix them.
    #![allow(unused_imports)]

    use core::borrow::{Borrow, BorrowMut};
    use core::str::pattern::{Pattern, Searcher, ReverseSearcher, DoubleEndedSearcher};
    use core::mem;
    use core::ptr;
    use core::iter::FusedIterator;
    use core::unicode::conversions;

    use crate::borrow::ToOwned;
    use crate::boxed::Box;
    use crate::slice::{SliceConcatExt, SliceIndex};
    use crate::string::String;
    use crate::vec::Vec;

    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::{FromStr, Utf8Error};
    #[allow(deprecated)]
    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::{Lines, LinesAny};
    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::{Split, RSplit};
    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::{SplitN, RSplitN};
    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::{SplitTerminator, RSplitTerminator};
    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::{Matches, RMatches};
    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::{MatchIndices, RMatchIndices};
    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::{from_utf8, from_utf8_mut, Chars, CharIndices, Bytes};
    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::{from_utf8_unchecked, from_utf8_unchecked_mut, ParseBoolError};
    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::SplitWhitespace;
    #[stable(feature = "rust1", since = "1.0.0")]
    pub use core::str::pattern;
    #[stable(feature = "encode_utf16", since = "1.8.0")]
    pub use core::str::EncodeUtf16;
    #[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
    pub use core::str::SplitAsciiWhitespace;
    #[stable(feature = "str_escape", since = "1.34.0")]
    pub use core::str::{EscapeDebug, EscapeDefault, EscapeUnicode};

    #[unstable(feature = "slice_concat_ext",
               reason = "trait should not have to exist",
               issue = "27747")]
    impl<S: Borrow<str>> SliceConcatExt<str> for [S] {
        type Output = String;

        fn concat(&self) -> String {
            self.join("")
        }

        fn join(&self, sep: &str) -> String {
            unsafe {
                String::from_utf8_unchecked( join_generic_copy(self, sep.as_bytes()) )
            }
        }
    }

    macro_rules! spezialize_for_lengths {
        ($separator:expr, $target:expr, $iter:expr; $($num:expr),*) => {
            let mut target = $target;
            let iter = $iter;
            let sep_bytes = $separator;
            match $separator.len() {
                $(
                    // loops with hardcoded sizes run much faster
                    // specialize the cases with small separator lengths
                    $num => {
                        for s in iter {
                            copy_slice_and_advance!(target, sep_bytes);
                            copy_slice_and_advance!(target, s.borrow().as_ref());
                        }
                    },
                )*
                _ => {
                    // arbitrary non-zero size fallback
                    for s in iter {
                        copy_slice_and_advance!(target, sep_bytes);
                        copy_slice_and_advance!(target, s.borrow().as_ref());
                    }
                }
            }
        };
    }

    macro_rules! copy_slice_and_advance {
        ($target:expr, $bytes:expr) => {
            let len = $bytes.len();
            let (head, tail) = {$target}.split_at_mut(len);
            head.copy_from_slice($bytes);
            $target = tail;
        }
    }

    // Optimized join implementation that works for both Vec<T> (T: Copy) and String's inner vec
    // Currently (2018-05-13) there is a bug with type inference and specialization (see issue #36262)
    // For this reason SliceConcatExt<T> is not specialized for T: Copy and SliceConcatExt<str> is the
    // only user of this function. It is left in place for the time when that is fixed.
    //
    // the bounds for String-join are S: Borrow<str> and for Vec-join Borrow<[T]>
    // [T] and str both impl AsRef<[T]> for some T
    // => s.borrow().as_ref() and we always have slices
    fn join_generic_copy<B, T, S>(slice: &[S], sep: &[T]) -> Vec<T>
    where
        T: Copy,
        B: AsRef<[T]> + ?Sized,
        S: Borrow<B>,
    {
        let sep_len = sep.len();
        let mut iter = slice.iter();

        // the first slice is the only one without a separator preceding it
        let first = match iter.next() {
            Some(first) => first,
            None => return vec![],
        };

        // compute the exact total length of the joined Vec
        // if the `len` calculation overflows, we'll panic
        // we would have run out of memory anyway and the rest of the function requires
        // the entire Vec pre-allocated for safety
        let len =  sep_len.checked_mul(iter.len()).and_then(|n| {
                slice.iter()
                    .map(|s| s.borrow().as_ref().len())
                    .try_fold(n, usize::checked_add)
            }).expect("attempt to join into collection with len > usize::MAX");

        // crucial for safety
        let mut result = Vec::with_capacity(len);
        assert!(result.capacity() >= len);

        result.extend_from_slice(first.borrow().as_ref());

        unsafe {
            {
                let pos = result.len();
                let target = result.get_unchecked_mut(pos..len);

                // copy separator and slices over without bounds checks
                // generate loops with hardcoded offsets for small separators
                // massive improvements possible (~ x2)
                spezialize_for_lengths!(sep, target, iter; 0, 1, 2, 3, 4);
            }
            result.set_len(len);
        }
        result
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl Borrow<str> for String {
        #[inline]
        fn borrow(&self) -> &str {
            &self[..]
        }
    }

    #[stable(feature = "string_borrow_mut", since = "1.36.0")]
    impl BorrowMut<str> for String {
        #[inline]
        fn borrow_mut(&mut self) -> &mut str {
            &mut self[..]
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl ToOwned for str {
        type Owned = String;
        #[inline]
        fn to_owned(&self) -> String {
            unsafe { String::from_utf8_unchecked(self.as_bytes().to_owned()) }
        }

        fn clone_into(&self, target: &mut String) {
            let mut b = mem::replace(target, String::new()).into_bytes();
            self.as_bytes().clone_into(&mut b);
            *target = unsafe { String::from_utf8_unchecked(b) }
        }
    }

    /// Methods for string slices.
    #[lang = "str_alloc"]
    #[cfg(not(test))]
    impl str {
        /// Converts a `Box<str>` into a `Box<[u8]>` without copying or allocating.
        ///
        /// # Examples
        ///
        /// Basic usage:
        ///
        /// ```
        /// let s = "this is a string";
        /// let boxed_str = s.to_owned().into_boxed_str();
        /// let boxed_bytes = boxed_str.into_boxed_bytes();
        /// assert_eq!(*boxed_bytes, *s.as_bytes());
        /// ```
        #[stable(feature = "str_box_extras", since = "1.20.0")]
        #[inline]
        pub fn into_boxed_bytes(self: Box<str>) -> Box<[u8]> {
            self.into()
        }

        /// Replaces all matches of a pattern with another string.
        ///
        /// `replace` creates a new [`String`], and copies the data from this string slice into it.
        /// While doing so, it attempts to find matches of a pattern. If it finds any, it
        /// replaces them with the replacement string slice.
        ///
        /// [`String`]: string/struct.String.html
        ///
        /// # Examples
        ///
        /// Basic usage:
        ///
        /// ```
        /// let s = "this is old";
        ///
        /// assert_eq!("this is new", s.replace("old", "new"));
        /// ```
        ///
        /// When the pattern doesn't match:
        ///
        /// ```
        /// let s = "this is old";
        /// assert_eq!(s, s.replace("cookie monster", "little lamb"));
        /// ```
        #[must_use = "this returns the replaced string as a new allocation, \
                      without modifying the original"]
        #[stable(feature = "rust1", since = "1.0.0")]
        #[inline]
        pub fn replace<'a, P: Pattern<'a>>(&'a self, from: P, to: &str) -> String {
            let mut result = String::new();
            let mut last_end = 0;
            for (start, part) in self.match_indices(from) {
                result.push_str(unsafe { self.get_unchecked(last_end..start) });
                result.push_str(to);
                last_end = start + part.len();
            }
            result.push_str(unsafe { self.get_unchecked(last_end..self.len()) });
            result
        }

        /// Replaces first N matches of a pattern with another string.
        ///
        /// `replacen` creates a new [`String`], and copies the data from this string slice into it.
        /// While doing so, it attempts to find matches of a pattern. If it finds any, it
        /// replaces them with the replacement string slice at most `count` times.
        ///
        /// [`String`]: string/struct.String.html
        ///
        /// # Examples
        ///
        /// Basic usage:
        ///
        /// ```
        /// let s = "foo foo 123 foo";
        /// assert_eq!("new new 123 foo", s.replacen("foo", "new", 2));
        /// assert_eq!("faa fao 123 foo", s.replacen('o', "a", 3));
        /// assert_eq!("foo foo new23 foo", s.replacen(char::is_numeric, "new", 1));
        /// ```
        ///
        /// When the pattern doesn't match:
        ///
        /// ```
        /// let s = "this is old";
        /// assert_eq!(s, s.replacen("cookie monster", "little lamb", 10));
        /// ```
        #[must_use = "this returns the replaced string as a new allocation, \
                      without modifying the original"]
        #[stable(feature = "str_replacen", since = "1.16.0")]
        pub fn replacen<'a, P: Pattern<'a>>(&'a self, pat: P, to: &str, count: usize) -> String {
            // Hope to reduce the times of re-allocation
            let mut result = String::with_capacity(32);
            let mut last_end = 0;
            for (start, part) in self.match_indices(pat).take(count) {
                result.push_str(unsafe { self.get_unchecked(last_end..start) });
                result.push_str(to);
                last_end = start + part.len();
            }
            result.push_str(unsafe { self.get_unchecked(last_end..self.len()) });
            result
        }

        /// Returns the lowercase equivalent of this string slice, as a new [`String`].
        ///
        /// 'Lowercase' is defined according to the terms of the Unicode Derived Core Property
        /// `Lowercase`.
        ///
        /// Since some characters can expand into multiple characters when changing
        /// the case, this function returns a [`String`] instead of modifying the
        /// parameter in-place.
        ///
        /// [`String`]: string/struct.String.html
        ///
        /// # Examples
        ///
        /// Basic usage:
        ///
        /// ```
        /// let s = "HELLO";
        ///
        /// assert_eq!("hello", s.to_lowercase());
        /// ```
        ///
        /// A tricky example, with sigma:
        ///
        /// ```
        /// let sigma = "Σ";
        ///
        /// assert_eq!("σ", sigma.to_lowercase());
        ///
        /// // but at the end of a word, it's ς, not σ:
        /// let odysseus = "ὈΔΥΣΣΕΎΣ";
        ///
        /// assert_eq!("ὀδυσσεύς", odysseus.to_lowercase());
        /// ```
        ///
        /// Languages without case are not changed:
        ///
        /// ```
        /// let new_year = "农历新年";
        ///
        /// assert_eq!(new_year, new_year.to_lowercase());
        /// ```
        #[stable(feature = "unicode_case_mapping", since = "1.2.0")]
        pub fn to_lowercase(&self) -> String {
            let mut s = String::with_capacity(self.len());
            for (i, c) in self[..].char_indices() {
                if c == 'Σ' {
                    // Σ maps to σ, except at the end of a word where it maps to ς.
                    // This is the only conditional (contextual) but language-independent mapping
                    // in `SpecialCasing.txt`,
                    // so hard-code it rather than have a generic "condition" mechanism.
                    // See https://github.com/rust-lang/rust/issues/26035
                    map_uppercase_sigma(self, i, &mut s)
                } else {
                    match conversions::to_lower(c) {
                        [a, '\0', _] => s.push(a),
                        [a, b, '\0'] => {
                            s.push(a);
                            s.push(b);
                        }
                        [a, b, c] => {
                            s.push(a);
                            s.push(b);
                            s.push(c);
                        }
                    }
                }
            }
            return s;

            fn map_uppercase_sigma(from: &str, i: usize, to: &mut String) {
                // See http://www.unicode.org/versions/Unicode7.0.0/ch03.pdf#G33992
                // for the definition of `Final_Sigma`.
                debug_assert!('Σ'.len_utf8() == 2);
                let is_word_final = case_ignoreable_then_cased(from[..i].chars().rev()) &&
                                    !case_ignoreable_then_cased(from[i + 2..].chars());
                to.push_str(if is_word_final { "ς" } else { "σ" });
            }

            fn case_ignoreable_then_cased<I: Iterator<Item = char>>(iter: I) -> bool {
                use core::unicode::derived_property::{Cased, Case_Ignorable};
                match iter.skip_while(|&c| Case_Ignorable(c)).next() {
                    Some(c) => Cased(c),
                    None => false,
                }
            }
        }

        /// Returns the uppercase equivalent of this string slice, as a new [`String`].
        ///
        /// 'Uppercase' is defined according to the terms of the Unicode Derived Core Property
        /// `Uppercase`.
        ///
        /// Since some characters can expand into multiple characters when changing
        /// the case, this function returns a [`String`] instead of modifying the
        /// parameter in-place.
        ///
        /// [`String`]: string/struct.String.html
        ///
        /// # Examples
        ///
        /// Basic usage:
        ///
        /// ```
        /// let s = "hello";
        ///
        /// assert_eq!("HELLO", s.to_uppercase());
        /// ```
        ///
        /// Scripts without case are not changed:
        ///
        /// ```
        /// let new_year = "农历新年";
        ///
        /// assert_eq!(new_year, new_year.to_uppercase());
        /// ```
        ///
        /// One character can become multiple:
        /// ```
        /// let s = "tschüß";
        ///
        /// assert_eq!("TSCHÜSS", s.to_uppercase());
        /// ```
        #[stable(feature = "unicode_case_mapping", since = "1.2.0")]
        pub fn to_uppercase(&self) -> String {
            let mut s = String::with_capacity(self.len());
            for c in self[..].chars() {
                match conversions::to_upper(c) {
                    [a, '\0', _] => s.push(a),
                    [a, b, '\0'] => {
                        s.push(a);
                        s.push(b);
                    }
                    [a, b, c] => {
                        s.push(a);
                        s.push(b);
                        s.push(c);
                    }
                }
            }
            return s;
        }

        /// Converts a [`Box<str>`] into a [`String`] without copying or allocating.
        ///
        /// [`String`]: string/struct.String.html
        /// [`Box<str>`]: boxed/struct.Box.html
        ///
        /// # Examples
        ///
        /// Basic usage:
        ///
        /// ```
        /// let string = String::from("birthday gift");
        /// let boxed_str = string.clone().into_boxed_str();
        ///
        /// assert_eq!(boxed_str.into_string(), string);
        /// ```
        #[stable(feature = "box_str", since = "1.4.0")]
        #[inline]
        pub fn into_string(self: Box<str>) -> String {
            let slice = Box::<[u8]>::from(self);
            unsafe { String::from_utf8_unchecked(slice.into_vec()) }
        }

        /// Creates a new [`String`] by repeating a string `n` times.
        ///
        /// # Panics
        ///
        /// This function will panic if the capacity would overflow.
        ///
        /// [`String`]: string/struct.String.html
        ///
        /// # Examples
        ///
        /// Basic usage:
        ///
        /// ```
        /// assert_eq!("abc".repeat(4), String::from("abcabcabcabc"));
        /// ```
        ///
        /// A panic upon overflow:
        ///
        /// ```should_panic
        /// fn main() {
        ///     // this will panic at runtime
        ///     "0123456789abcdef".repeat(usize::max_value());
        /// }
        /// ```
        #[stable(feature = "repeat_str", since = "1.16.0")]
        pub fn repeat(&self, n: usize) -> String {
            unsafe { String::from_utf8_unchecked(self.as_bytes().repeat(n)) }
        }

        /// Returns a copy of this string where each character is mapped to its
        /// ASCII upper case equivalent.
        ///
        /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
        /// but non-ASCII letters are unchanged.
        ///
        /// To uppercase the value in-place, use [`make_ascii_uppercase`].
        ///
        /// To uppercase ASCII characters in addition to non-ASCII characters, use
        /// [`to_uppercase`].
        ///
        /// # Examples
        ///
        /// ```
        /// let s = "Grüße, Jürgen ❤";
        ///
        /// assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase());
        /// ```
        ///
        /// [`make_ascii_uppercase`]: #method.make_ascii_uppercase
        /// [`to_uppercase`]: #method.to_uppercase
        #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
        #[inline]
        pub fn to_ascii_uppercase(&self) -> String {
            let mut bytes = self.as_bytes().to_vec();
            bytes.make_ascii_uppercase();
            // make_ascii_uppercase() preserves the UTF-8 invariant.
            unsafe { String::from_utf8_unchecked(bytes) }
        }

        /// Returns a copy of this string where each character is mapped to its
        /// ASCII lower case equivalent.
        ///
        /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
        /// but non-ASCII letters are unchanged.
        ///
        /// To lowercase the value in-place, use [`make_ascii_lowercase`].
        ///
        /// To lowercase ASCII characters in addition to non-ASCII characters, use
        /// [`to_lowercase`].
        ///
        /// # Examples
        ///
        /// ```
        /// let s = "Grüße, Jürgen ❤";
        ///
        /// assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase());
        /// ```
        ///
        /// [`make_ascii_lowercase`]: #method.make_ascii_lowercase
        /// [`to_lowercase`]: #method.to_lowercase
        #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
        #[inline]
        pub fn to_ascii_lowercase(&self) -> String {
            let mut bytes = self.as_bytes().to_vec();
            bytes.make_ascii_lowercase();
            // make_ascii_lowercase() preserves the UTF-8 invariant.
            unsafe { String::from_utf8_unchecked(bytes) }
        }
    }

    /// Converts a boxed slice of bytes to a boxed string slice without checking
    /// that the string contains valid UTF-8.
    ///
    /// # Examples
    ///
    /// Basic usage:
    ///
    /// ```
    /// let smile_utf8 = Box::new([226, 152, 186]);
    /// let smile = unsafe { std::str::from_boxed_utf8_unchecked(smile_utf8) };
    ///
    /// assert_eq!("☺", &*smile);
    /// ```
    #[stable(feature = "str_box_extras", since = "1.20.0")]
    #[inline]
    pub unsafe fn from_boxed_utf8_unchecked(v: Box<[u8]>) -> Box<str> {
        Box::from_raw(Box::into_raw(v) as *mut str)
    }

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g., `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g., `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g., `str,u8` or `String,struct:Vec,test`)