Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

add regex::Match len method #810

Closed
gabenodarse opened this issue Oct 21, 2021 · 2 comments
Closed

add regex::Match len method #810

gabenodarse opened this issue Oct 21, 2021 · 2 comments

Comments

@gabenodarse
Copy link

Describe your feature request

Match (regex::Match) represents a group match and has 4 methods, start, end, range, and as_str. While those methods are sufficient, I think len should be added. The reason simply is that I would prefer to use start + len rather than end, because I can't tell immediately if end refers to the last character or the 1 + the last character (it refers to 1 + the last character).

For instance, if I'm replacing a match m from original sting original_str, I would use:

original_str.replace_range(m.start() .. m.start() + m.len(), "foo")

rather than

original_str.replace_range(m.start()..m.end(), "foo")

I'm sure there are other instances where developers would prefer to use a len method, instances that make more sense than mine.

@BurntSushi
Copy link
Member

I know you said it, but the end of a range refers to the offset immediately following the last byte in the matched range. This is idiomatic and ubiquitous in the Rust ecosystem. I do not think a len method should be added for your use case because I consider using m.start() + m.len() to be quite odd given that m.end() exists. It's also potentially more costly, depending on whether the compiler optimizes it correctly or not.

Another idea here might be to add a range method that returns a std::ops::Range.

@gabenodarse
Copy link
Author

Thank you for the response. That end() refers to 1 after the last byte is what I would expect, but I had not seen (enough) similar functions to be confident of that. It is good to know that it is idiomatic and ubiquitous.

BurntSushi added a commit that referenced this issue Mar 6, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Mar 15, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Mar 15, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Mar 15, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Mar 15, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Mar 15, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Mar 20, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Mar 21, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Apr 15, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Apr 15, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Apr 17, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Apr 17, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Apr 17, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Apr 17, 2023
Adding these methods has almost no cost and they can be convenient to
have in some cases.

Closes #810
BurntSushi added a commit that referenced this issue Apr 20, 2023
1.8.0 (2023-04-20)
==================
This is a sizeable release that will be soon followed by another sizeable
release. Both of them will combined close over 40 existing issues and PRs.

This first release, despite its size, essentially represent preparatory work
for the second release, which will be even bigger. Namely, this release:

* Increases the MSRV to Rust 1.60.0, which was released about 1 year ago.
* Upgrades its dependency on `aho-corasick` to the recently release 1.0
version.
* Upgrades its dependency on `regex-syntax` to the simultaneously released
`0.7` version. The changes to `regex-syntax` principally revolve around a
rewrite of its literal extraction code and a number of simplifications and
optimizations to its high-level intermediate representation (HIR).

The second release, which will follow ~shortly after the release above, will
contain a soup-to-nuts rewrite of every regex engine. This will be done by
bringing [`regex-automata`](https://github.com/BurntSushi/regex-automata) into
this repository, and then changing the `regex` crate to be nothing but an API
shim layer on top of `regex-automata`'s API.

These tandem releases are the culmination of about 3
years of on-and-off work that [began in earnest in March
2020](#656).

Because of the scale of changes involved in these releases, I would love to
hear about your experience. Especially if you notice undocumented changes in
behavior or performance changes (positive *or* negative).

Most changes in the first release are listed below. For more details, please
see the commit log, which reflects a linear and decently documented history
of all changes.

New features:

* [FEATURE #501](#501):
Permit many more characters to be escaped, even if they have no significance.
More specifically, any ASCII character except for `[0-9A-Za-z<>]` can now be
escaped. Also, a new routine, `is_escapeable_character`, has been added to
`regex-syntax` to query whether a character is escapeable or not.
* [FEATURE #547](#547):
Add `Regex::captures_at`. This filles a hole in the API, but doesn't otherwise
introduce any new expressive power.
* [FEATURE #595](#595):
Capture group names are now Unicode-aware. They can now begin with either a `_`
or any "alphabetic" codepoint. After the first codepoint, subsequent codepoints
can be any sequence of alpha-numeric codepoints, along with `_`, `.`, `[` and
`]`. Note that replacement syntax has not changed.
* [FEATURE #810](#810):
Add `Match::is_empty` and `Match::len` APIs.
* [FEATURE #905](#905):
Add an `impl Default for RegexSet`, with the default being the empty set.
* [FEATURE #908](#908):
A new method, `Regex::static_captures_len`, has been added which returns the
number of capture groups in the pattern if and only if every possible match
always contains the same number of matching groups.
* [FEATURE #955](#955):
Named captures can now be written as `(?<name>re)` in addition to
`(?P<name>re)`.
* FEATURE: `regex-syntax` now supports empty character classes.
* FEATURE: `regex-syntax` now has an optional `std` feature. (This will come
to `regex` in the second release.)
* FEATURE: The `Hir` type in `regex-syntax` has had a number of simplifications
made to it.
* FEATURE: `regex-syntax` has support for a new `R` flag for enabling CRLF
mode. This will be supported in `regex` proper in the second release.
* FEATURE: `regex-syntax` now has proper support for "regex that never
matches" via `Hir::fail()`.
* FEATURE: The `hir::literal` module of `regex-syntax` has been completely
re-worked. It now has more documentation, examples and advice.
* FEATURE: The `allow_invalid_utf8` option in `regex-syntax` has been renamed
to `utf8`, and the meaning of the boolean has been flipped.

Performance improvements:

* PERF: The upgrade to `aho-corasick 1.0` may improve performance in some
cases. It's difficult to characterize exactly which patterns this might impact,
but if there are a small number of longish (>= 4 bytes) prefix literals, then
it might be faster than before.

Bug fixes:

* [BUG #514](#514):
Improve `Debug` impl for `Match` so that it doesn't show the entire haystack.
* BUGS [#516](#516),
[#731](#731):
Fix a number of issues with printing `Hir` values as regex patterns.
* [BUG #610](#610):
Add explicit example of `foo|bar` in the regex syntax docs.
* [BUG #625](#625):
Clarify that `SetMatches::len` does not (regretably) refer to the number of
matches in the set.
* [BUG #660](#660):
Clarify "verbose mode" in regex syntax documentation.
* BUG [#738](#738),
[#950](#950):
Fix `CaptureLocations::get` so that it never panics.
* [BUG #747](#747):
Clarify documentation for `Regex::shortest_match`.
* [BUG #835](#835):
Fix `\p{Sc}` so that it is equivalent to `\p{Currency_Symbol}`.
* [BUG #846](#846):
Add more clarifying documentation to the `CompiledTooBig` error variant.
* [BUG #854](#854):
Clarify that `regex::Regex` searches as if the haystack is a sequence of
Unicode scalar values.
* [BUG #884](#884):
Replace `__Nonexhaustive` variants with `#[non_exhaustive]` attribute.
* [BUG #893](#893):
Optimize case folding since it can get quite slow in some pathological cases.
* [BUG #895](#895):
Reject `(?-u:\W)` in `regex::Regex` APIs.
* [BUG #942](#942):
Add a missing `void` keyword to indicate "no parameters" in C API.
* [BUG #965](#965):
Fix `\p{Lc}` so that it is equivalent to `\p{Cased_Letter}`.
* [BUG #975](#975):
Clarify documentation for `\pX` syntax.
BurntSushi added a commit that referenced this issue Apr 20, 2023
1.8.0 (2023-04-20)
==================
This is a sizeable release that will be soon followed by another sizeable
release. Both of them will combined close over 40 existing issues and PRs.

This first release, despite its size, essentially represent preparatory work
for the second release, which will be even bigger. Namely, this release:

* Increases the MSRV to Rust 1.60.0, which was released about 1 year ago.
* Upgrades its dependency on `aho-corasick` to the recently release 1.0
version.
* Upgrades its dependency on `regex-syntax` to the simultaneously released
`0.7` version. The changes to `regex-syntax` principally revolve around a
rewrite of its literal extraction code and a number of simplifications and
optimizations to its high-level intermediate representation (HIR).

The second release, which will follow ~shortly after the release above, will
contain a soup-to-nuts rewrite of every regex engine. This will be done by
bringing [`regex-automata`](https://github.com/BurntSushi/regex-automata) into
this repository, and then changing the `regex` crate to be nothing but an API
shim layer on top of `regex-automata`'s API.

These tandem releases are the culmination of about 3
years of on-and-off work that [began in earnest in March
2020](#656).

Because of the scale of changes involved in these releases, I would love to
hear about your experience. Especially if you notice undocumented changes in
behavior or performance changes (positive *or* negative).

Most changes in the first release are listed below. For more details, please
see the commit log, which reflects a linear and decently documented history
of all changes.

New features:

* [FEATURE #501](#501):
Permit many more characters to be escaped, even if they have no significance.
More specifically, any ASCII character except for `[0-9A-Za-z<>]` can now be
escaped. Also, a new routine, `is_escapeable_character`, has been added to
`regex-syntax` to query whether a character is escapeable or not.
* [FEATURE #547](#547):
Add `Regex::captures_at`. This filles a hole in the API, but doesn't otherwise
introduce any new expressive power.
* [FEATURE #595](#595):
Capture group names are now Unicode-aware. They can now begin with either a `_`
or any "alphabetic" codepoint. After the first codepoint, subsequent codepoints
can be any sequence of alpha-numeric codepoints, along with `_`, `.`, `[` and
`]`. Note that replacement syntax has not changed.
* [FEATURE #810](#810):
Add `Match::is_empty` and `Match::len` APIs.
* [FEATURE #905](#905):
Add an `impl Default for RegexSet`, with the default being the empty set.
* [FEATURE #908](#908):
A new method, `Regex::static_captures_len`, has been added which returns the
number of capture groups in the pattern if and only if every possible match
always contains the same number of matching groups.
* [FEATURE #955](#955):
Named captures can now be written as `(?<name>re)` in addition to
`(?P<name>re)`.
* FEATURE: `regex-syntax` now supports empty character classes.
* FEATURE: `regex-syntax` now has an optional `std` feature. (This will come
to `regex` in the second release.)
* FEATURE: The `Hir` type in `regex-syntax` has had a number of simplifications
made to it.
* FEATURE: `regex-syntax` has support for a new `R` flag for enabling CRLF
mode. This will be supported in `regex` proper in the second release.
* FEATURE: `regex-syntax` now has proper support for "regex that never
matches" via `Hir::fail()`.
* FEATURE: The `hir::literal` module of `regex-syntax` has been completely
re-worked. It now has more documentation, examples and advice.
* FEATURE: The `allow_invalid_utf8` option in `regex-syntax` has been renamed
to `utf8`, and the meaning of the boolean has been flipped.

Performance improvements:

* PERF: The upgrade to `aho-corasick 1.0` may improve performance in some
cases. It's difficult to characterize exactly which patterns this might impact,
but if there are a small number of longish (>= 4 bytes) prefix literals, then
it might be faster than before.

Bug fixes:

* [BUG #514](#514):
Improve `Debug` impl for `Match` so that it doesn't show the entire haystack.
* BUGS [#516](#516),
[#731](#731):
Fix a number of issues with printing `Hir` values as regex patterns.
* [BUG #610](#610):
Add explicit example of `foo|bar` in the regex syntax docs.
* [BUG #625](#625):
Clarify that `SetMatches::len` does not (regretably) refer to the number of
matches in the set.
* [BUG #660](#660):
Clarify "verbose mode" in regex syntax documentation.
* BUG [#738](#738),
[#950](#950):
Fix `CaptureLocations::get` so that it never panics.
* [BUG #747](#747):
Clarify documentation for `Regex::shortest_match`.
* [BUG #835](#835):
Fix `\p{Sc}` so that it is equivalent to `\p{Currency_Symbol}`.
* [BUG #846](#846):
Add more clarifying documentation to the `CompiledTooBig` error variant.
* [BUG #854](#854):
Clarify that `regex::Regex` searches as if the haystack is a sequence of
Unicode scalar values.
* [BUG #884](#884):
Replace `__Nonexhaustive` variants with `#[non_exhaustive]` attribute.
* [BUG #893](#893):
Optimize case folding since it can get quite slow in some pathological cases.
* [BUG #895](#895):
Reject `(?-u:\W)` in `regex::Regex` APIs.
* [BUG #942](#942):
Add a missing `void` keyword to indicate "no parameters" in C API.
* [BUG #965](#965):
Fix `\p{Lc}` so that it is equivalent to `\p{Cased_Letter}`.
* [BUG #975](#975):
Clarify documentation for `\pX` syntax.
crapStone added a commit to Calciumdibromid/CaBr2 that referenced this issue May 2, 2023
This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [regex](https://github.com/rust-lang/regex) | dependencies | minor | `1.7.3` -> `1.8.1` |

---

### Release Notes

<details>
<summary>rust-lang/regex</summary>

### [`v1.8.1`](https://github.com/rust-lang/regex/blob/HEAD/CHANGELOG.md#&#8203;181-2023-04-21)

\==================
This is a patch release that fixes a bug where a regex match could be reported
where none was found. Specifically, the bug occurs when a pattern contains some
literal prefixes that could be extracted *and* an optional word boundary in the
prefix.

Bug fixes:

-   [BUG #&#8203;981](rust-lang/regex#981):
    Fix a bug where a word boundary could interact with prefix literal
    optimizations and lead to a false positive match.

### [`v1.8.0`](https://github.com/rust-lang/regex/blob/HEAD/CHANGELOG.md#&#8203;180-2023-04-20)

\==================
This is a sizeable release that will be soon followed by another sizeable
release. Both of them will combined close over 40 existing issues and PRs.

This first release, despite its size, essentially represents preparatory work
for the second release, which will be even bigger. Namely, this release:

-   Increases the MSRV to Rust 1.60.0, which was released about 1 year ago.
-   Upgrades its dependency on `aho-corasick` to the recently released 1.0
    version.
-   Upgrades its dependency on `regex-syntax` to the simultaneously released
    `0.7` version. The changes to `regex-syntax` principally revolve around a
    rewrite of its literal extraction code and a number of simplifications and
    optimizations to its high-level intermediate representation (HIR).

The second release, which will follow ~shortly after the release above, will
contain a soup-to-nuts rewrite of every regex engine. This will be done by
bringing [`regex-automata`](https://github.com/BurntSushi/regex-automata) into
this repository, and then changing the `regex` crate to be nothing but an API
shim layer on top of `regex-automata`'s API.

These tandem releases are the culmination of about 3
years of on-and-off work that [began in earnest in March
2020](rust-lang/regex#656).

Because of the scale of changes involved in these releases, I would love to
hear about your experience. Especially if you notice undocumented changes in
behavior or performance changes (positive *or* negative).

Most changes in the first release are listed below. For more details, please
see the commit log, which reflects a linear and decently documented history
of all changes.

New features:

-   [FEATURE #&#8203;501](rust-lang/regex#501):
    Permit many more characters to be escaped, even if they have no significance.
    More specifically, any ASCII character except for `[0-9A-Za-z<>]` can now be
    escaped. Also, a new routine, `is_escapeable_character`, has been added to
    `regex-syntax` to query whether a character is escapeable or not.
-   [FEATURE #&#8203;547](rust-lang/regex#547):
    Add `Regex::captures_at`. This filles a hole in the API, but doesn't otherwise
    introduce any new expressive power.
-   [FEATURE #&#8203;595](rust-lang/regex#595):
    Capture group names are now Unicode-aware. They can now begin with either a `_`
    or any "alphabetic" codepoint. After the first codepoint, subsequent codepoints
    can be any sequence of alpha-numeric codepoints, along with `_`, `.`, `[` and
    `]`. Note that replacement syntax has not changed.
-   [FEATURE #&#8203;810](rust-lang/regex#810):
    Add `Match::is_empty` and `Match::len` APIs.
-   [FEATURE #&#8203;905](rust-lang/regex#905):
    Add an `impl Default for RegexSet`, with the default being the empty set.
-   [FEATURE #&#8203;908](rust-lang/regex#908):
    A new method, `Regex::static_captures_len`, has been added which returns the
    number of capture groups in the pattern if and only if every possible match
    always contains the same number of matching groups.
-   [FEATURE #&#8203;955](rust-lang/regex#955):
    Named captures can now be written as `(?<name>re)` in addition to
    `(?P<name>re)`.
-   FEATURE: `regex-syntax` now supports empty character classes.
-   FEATURE: `regex-syntax` now has an optional `std` feature. (This will come
    to `regex` in the second release.)
-   FEATURE: The `Hir` type in `regex-syntax` has had a number of simplifications
    made to it.
-   FEATURE: `regex-syntax` has support for a new `R` flag for enabling CRLF
    mode. This will be supported in `regex` proper in the second release.
-   FEATURE: `regex-syntax` now has proper support for "regex that never
    matches" via `Hir::fail()`.
-   FEATURE: The `hir::literal` module of `regex-syntax` has been completely
    re-worked. It now has more documentation, examples and advice.
-   FEATURE: The `allow_invalid_utf8` option in `regex-syntax` has been renamed
    to `utf8`, and the meaning of the boolean has been flipped.

Performance improvements:

-   PERF: The upgrade to `aho-corasick 1.0` may improve performance in some
    cases. It's difficult to characterize exactly which patterns this might impact,
    but if there are a small number of longish (>= 4 bytes) prefix literals, then
    it might be faster than before.

Bug fixes:

-   [BUG #&#8203;514](rust-lang/regex#514):
    Improve `Debug` impl for `Match` so that it doesn't show the entire haystack.
-   BUGS [#&#8203;516](rust-lang/regex#516),
    [#&#8203;731](rust-lang/regex#731):
    Fix a number of issues with printing `Hir` values as regex patterns.
-   [BUG #&#8203;610](rust-lang/regex#610):
    Add explicit example of `foo|bar` in the regex syntax docs.
-   [BUG #&#8203;625](rust-lang/regex#625):
    Clarify that `SetMatches::len` does not (regretably) refer to the number of
    matches in the set.
-   [BUG #&#8203;660](rust-lang/regex#660):
    Clarify "verbose mode" in regex syntax documentation.
-   BUG [#&#8203;738](rust-lang/regex#738),
    [#&#8203;950](rust-lang/regex#950):
    Fix `CaptureLocations::get` so that it never panics.
-   [BUG #&#8203;747](rust-lang/regex#747):
    Clarify documentation for `Regex::shortest_match`.
-   [BUG #&#8203;835](rust-lang/regex#835):
    Fix `\p{Sc}` so that it is equivalent to `\p{Currency_Symbol}`.
-   [BUG #&#8203;846](rust-lang/regex#846):
    Add more clarifying documentation to the `CompiledTooBig` error variant.
-   [BUG #&#8203;854](rust-lang/regex#854):
    Clarify that `regex::Regex` searches as if the haystack is a sequence of
    Unicode scalar values.
-   [BUG #&#8203;884](rust-lang/regex#884):
    Replace `__Nonexhaustive` variants with `#[non_exhaustive]` attribute.
-   [BUG #&#8203;893](rust-lang/regex#893):
    Optimize case folding since it can get quite slow in some pathological cases.
-   [BUG #&#8203;895](rust-lang/regex#895):
    Reject `(?-u:\W)` in `regex::Regex` APIs.
-   [BUG #&#8203;942](rust-lang/regex#942):
    Add a missing `void` keyword to indicate "no parameters" in C API.
-   [BUG #&#8203;965](rust-lang/regex#965):
    Fix `\p{Lc}` so that it is equivalent to `\p{Cased_Letter}`.
-   [BUG #&#8203;975](rust-lang/regex#975):
    Clarify documentation for `\pX` syntax.

</details>

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNS42MS4wIiwidXBkYXRlZEluVmVyIjoiMzUuNjYuMyIsInRhcmdldEJyYW5jaCI6ImRldmVsb3AifQ==-->

Co-authored-by: cabr2-bot <cabr2.help@gmail.com>
Co-authored-by: crapStone <crapstone01@gmail.com>
Reviewed-on: https://codeberg.org/Calciumdibromid/CaBr2/pulls/1874
Reviewed-by: crapStone <crapstone@noreply.codeberg.org>
Co-authored-by: Calciumdibromid Bot <cabr2_bot@noreply.codeberg.org>
Co-committed-by: Calciumdibromid Bot <cabr2_bot@noreply.codeberg.org>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Projects
None yet
Development

No branches or pull requests

2 participants