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Rollup merge of rust-lang#71334 - ehuss:pattern-docs, r=kennytm
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Update pattern docs.

A few changes to help clarify string pattern usage:

* Add some examples and stability information in the `pattern` module.
* Fixes the links at https://doc.rust-lang.org/std/str/pattern/ because intra-doc-links don't work with re-exported modules (rust-lang#65983 I think?).
* Consistently use the same phrasing for `str` methods taking a pattern.
    * Also mention that array of `char` is also accepted.

When `Pattern` is stabilized, the phrasing in the `str` methods can be updated to be more general to reflect the exact behavior. I'm reluctant to do this now because the stability story for `Pattern` is uncertain. It may perhaps look something like:

> The pattern can be any type that implements the [`Pattern`] trait. Notable examples are `&str`, [`char`], arrays of [`char`], or functions or closures that determines if a character matches. Additional libraries might provide more complex patterns like regular expressions.

This is complicated because methods like `trim_matches` have bounds, which for example don't support `str`, so those methods may need more elaboration.
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@Dylan-DPC
Dylan-DPC authored Apr 20, 2020
2 parents 156ed10 + ca61fd5 commit db64e00
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151 changes: 115 additions & 36 deletions src/libcore/str/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3010,6 +3010,12 @@ impl str {
///
/// Returns `false` if it does not.
///
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Examples
///
/// Basic usage:
Expand All @@ -3031,6 +3037,12 @@ impl str {
///
/// Returns `false` if it does not.
///
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Examples
///
/// Basic usage:
Expand All @@ -3051,6 +3063,12 @@ impl str {
///
/// Returns `false` if it does not.
///
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Examples
///
/// Basic usage:
Expand All @@ -3074,10 +3092,12 @@ impl str {
///
/// Returns [`None`] if the pattern doesn't match.
///
/// The pattern can be a `&str`, [`char`], or a closure that determines if
/// a character matches.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`None`]: option/enum.Option.html#variant.None
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Examples
///
Expand Down Expand Up @@ -3121,10 +3141,12 @@ impl str {
///
/// Returns [`None`] if the pattern doesn't match.
///
/// The pattern can be a `&str`, [`char`], or a closure that determines if
/// a character matches.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`None`]: option/enum.Option.html#variant.None
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Examples
///
Expand Down Expand Up @@ -3166,8 +3188,11 @@ impl str {
/// An iterator over substrings of this string slice, separated by
/// characters matched by a pattern.
///
/// The pattern can be any type that implements the Pattern trait. Notable
/// examples are `&str`, [`char`], and closures that determines the split.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Iterator behavior
///
Expand Down Expand Up @@ -3285,6 +3310,12 @@ impl str {
/// `split` in that `split_inclusive` leaves the matched part as the
/// terminator of the substring.
///
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Examples
///
/// ```
Expand Down Expand Up @@ -3319,8 +3350,11 @@ impl str {
/// An iterator over substrings of the given string slice, separated by
/// characters matched by a pattern and yielded in reverse order.
///
/// The pattern can be any type that implements the Pattern trait. Notable
/// examples are `&str`, [`char`], and closures that determines the split.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Iterator behavior
///
Expand Down Expand Up @@ -3370,8 +3404,11 @@ impl str {
/// An iterator over substrings of the given string slice, separated by
/// characters matched by a pattern.
///
/// The pattern can be any type that implements the Pattern trait. Notable
/// examples are `&str`, [`char`], and closures that determines the split.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// Equivalent to [`split`], except that the trailing substring
/// is skipped if empty.
Expand Down Expand Up @@ -3414,10 +3451,11 @@ impl str {
/// An iterator over substrings of `self`, separated by characters
/// matched by a pattern and yielded in reverse order.
///
/// The pattern can be any type that implements the Pattern trait. Notable
/// examples are `&str`, [`char`], and closures that determines the split.
/// Additional libraries might provide more complex patterns like
/// regular expressions.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// Equivalent to [`split`], except that the trailing substring is
/// skipped if empty.
Expand Down Expand Up @@ -3462,8 +3500,11 @@ impl str {
/// If `n` substrings are returned, the last substring (the `n`th substring)
/// will contain the remainder of the string.
///
/// The pattern can be any type that implements the Pattern trait. Notable
/// examples are `&str`, [`char`], and closures that determines the split.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Iterator behavior
///
Expand Down Expand Up @@ -3512,8 +3553,11 @@ impl str {
/// If `n` substrings are returned, the last substring (the `n`th substring)
/// will contain the remainder of the string.
///
/// The pattern can be any type that implements the Pattern trait. Notable
/// examples are `&str`, [`char`], and closures that determines the split.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Iterator behavior
///
Expand Down Expand Up @@ -3557,8 +3601,11 @@ impl str {
/// An iterator over the disjoint matches of a pattern within the given string
/// slice.
///
/// The pattern can be a `&str`, [`char`], or a closure that determines if
/// a character matches.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Iterator behavior
///
Expand Down Expand Up @@ -3593,8 +3640,11 @@ impl str {
/// An iterator over the disjoint matches of a pattern within this string slice,
/// yielded in reverse order.
///
/// The pattern can be a `&str`, [`char`], or a closure that determines if
/// a character matches.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Iterator behavior
///
Expand Down Expand Up @@ -3634,8 +3684,11 @@ impl str {
/// For matches of `pat` within `self` that overlap, only the indices
/// corresponding to the first match are returned.
///
/// The pattern can be a `&str`, [`char`], or a closure that determines
/// if a character matches.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Iterator behavior
///
Expand Down Expand Up @@ -3676,8 +3729,11 @@ impl str {
/// For matches of `pat` within `self` that overlap, only the indices
/// corresponding to the last match are returned.
///
/// The pattern can be a `&str`, [`char`], or a closure that determines if a
/// character matches.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Iterator behavior
///
Expand Down Expand Up @@ -3894,8 +3950,11 @@ impl str {
/// Returns a string slice with all prefixes and suffixes that match a
/// pattern repeatedly removed.
///
/// The pattern can be a [`char`] or a closure that determines if a
/// character matches.
/// The [pattern] can be a [`char`], a slice of [`char`]s, or a function
/// or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Examples
///
Expand Down Expand Up @@ -3939,8 +3998,11 @@ impl str {
/// Returns a string slice with all prefixes that match a pattern
/// repeatedly removed.
///
/// The pattern can be a `&str`, [`char`], or a closure that determines if
/// a character matches.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Text directionality
///
Expand Down Expand Up @@ -3981,6 +4043,12 @@ impl str {
///
/// If the string does not start with `prefix`, `None` is returned.
///
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Examples
///
/// ```
Expand All @@ -4005,6 +4073,12 @@ impl str {
///
/// If the string does not end with `suffix`, `None` is returned.
///
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Examples
///
/// ```
Expand All @@ -4027,8 +4101,11 @@ impl str {
/// Returns a string slice with all suffixes that match a pattern
/// repeatedly removed.
///
/// The pattern can be a `&str`, [`char`], or a closure that
/// determines if a character matches.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Text directionality
///
Expand Down Expand Up @@ -4073,10 +4150,11 @@ impl str {
/// Returns a string slice with all prefixes that match a pattern
/// repeatedly removed.
///
/// The pattern can be a `&str`, [`char`], or a closure that determines if
/// a character matches.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Text directionality
///
Expand Down Expand Up @@ -4109,10 +4187,11 @@ impl str {
/// Returns a string slice with all suffixes that match a pattern
/// repeatedly removed.
///
/// The pattern can be a `&str`, [`char`], or a closure that
/// determines if a character matches.
/// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
/// function or closure that determines if a character matches.
///
/// [`char`]: primitive.char.html
/// [pattern]: str/pattern/index.html
///
/// # Text directionality
///
Expand Down
36 changes: 35 additions & 1 deletion src/libcore/str/pattern.rs
View file
Original file line number Diff line number Diff line change
@@ -1,7 +1,41 @@
//! The string Pattern API.
//!
//! The Pattern API provides a generic mechanism for using different pattern
//! types when searching through a string.
//!
//! For more details, see the traits [`Pattern`], [`Searcher`],
//! [`ReverseSearcher`], and [`DoubleEndedSearcher`].
//!
//! Although this API is unstable, it is exposed via stable APIs on the
//! [`str`] type.
//!
//! # Examples
//!
//! [`Pattern`] is [implemented][pattern-impls] in the stable API for
//! [`&str`], [`char`], slices of [`char`], and functions and closures
//! implementing `FnMut(char) -> bool`.
//!
//! ```
//! let s = "Can you find a needle in a haystack?";
//!
//! // &str pattern
//! assert_eq!(s.find("you"), Some(4));
//! // char pattern
//! assert_eq!(s.find('n'), Some(2));
//! // slice of chars pattern
//! assert_eq!(s.find(&['a', 'e', 'i', 'o', 'u'][..]), Some(1));
//! // closure pattern
//! assert_eq!(s.find(|c: char| c.is_ascii_punctuation()), Some(35));
//! ```
//!
//! [`&str`]: ../../../std/primitive.str.html
//! [`char`]: ../../../std/primitive.char.html
//! [`str`]: ../../../std/primitive.str.html
//! [`DoubleEndedSearcher`]: trait.DoubleEndedSearcher.html
//! [`Pattern`]: trait.Pattern.html
//! [`ReverseSearcher`]: trait.ReverseSearcher.html
//! [`Searcher`]: trait.Searcher.html
//! [pattern-impls]: trait.Pattern.html#implementors

#![unstable(
feature = "pattern",
Expand Down Expand Up @@ -702,7 +736,7 @@ unsafe impl<'a, 'b> ReverseSearcher<'a> for CharSliceSearcher<'a, 'b> {

impl<'a, 'b> DoubleEndedSearcher<'a> for CharSliceSearcher<'a, 'b> {}

/// Searches for chars that are equal to any of the chars in the array.
/// Searches for chars that are equal to any of the chars in the slice.
///
/// # Examples
///
Expand Down

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