crates/textwrap/CHANGELOG.md

# Changelog

This file lists the most important changes made in each release of `textwrap`.

## Version 0.16.2 (2025-03-03)

This release fixes an unnecessary `f64` cast, updates all dependencies, bumps
the minimum supported Rust version to 1.70.

- [#540](https://github.com/mgeisler/textwrap/pull/540): Avoid spurious `f64`
  cast and comparison.
- [#565](https://github.com/mgeisler/textwrap/pull/565): Configure automatic
  Dependabot updates.
- [#579](https://github.com/mgeisler/textwrap/pull/579): Bump `rust-version` to
  1.70.

## Version 0.16.1 (2024-02-17)

This release fixes `display_width` to ignore inline-hyperlinks. The minimum
supported version of Rust is now documented to be 1.56.

- [#526](https://github.com/mgeisler/textwrap/pull/526): Ignore ANSI hyperlinks
  in `display_width`: calculations.
- [#521](https://github.com/mgeisler/textwrap/pull/521): Add `Options::width`
  setter method.
- [#520](https://github.com/mgeisler/textwrap/pull/520): Clarify that
  `WordSeparator` is an enum rather than a trait.
- [#518](https://github.com/mgeisler/textwrap/pull/518): Test with latest stable
  and nightly Rust, but check that we can build with Rust 1.56.

## Version 0.16.0 (2022-10-23)

This release marks `Options` as `non_exhaustive` and extends it to make line
endings configurable, it adds new fast paths to `fill` and `wrap`, and it fixes
crashes in `unfill` and `refill`.

- [#480](https://github.com/mgeisler/textwrap/pull/480): Mark `Options` as
  `non_exhaustive`. This will allow us to extend the struct in the future
  without breaking backwards compatibility.
- [#478](https://github.com/mgeisler/textwrap/pull/478): Add fast paths to
  `fill` and `wrap`. This makes the functions 10-25 times faster when the no
  wrapping is needed.
- [#468](https://github.com/mgeisler/textwrap/pull/468): Fix `refill` to add
  back correct line ending.
- [#467](https://github.com/mgeisler/textwrap/pull/467): Fix crashes in `unfill`
  and `refill`.
- [#458](https://github.com/mgeisler/textwrap/pull/458): Test with Rust 1.56
  (first compiler release with support for Rust 2021).
- [#454](https://github.com/mgeisler/textwrap/pull/454): Make line endings
  configurable.
- [#448](https://github.com/mgeisler/textwrap/pull/448): Migrate to the Rust
  2021 edition.

## Version 0.15.2 (2022-10-24)

This release is identical to 0.15.0 and is only there to give people a way to
install crates which depend on the yanked 0.15.1 release. See
[#484](https://github.com/mgeisler/textwrap/issues/484) for details.

## Version 0.15.1 (2022-09-15)

This release was yanked since it accidentally broke backwards compatibility with
0.15.0.

## Version 0.15.0 (2022-02-27)

This is a major feature release with two main changes:

- [#421](https://github.com/mgeisler/textwrap/pull/421): Use `f64` instead of
  `usize` for fragment widths.

  This fixes problems with overflows in the internal computations of
  `wrap_optimal_fit` when fragments (words) or line lengths had extreme values,
  such as `usize::MAX`.

- [#438](https://github.com/mgeisler/textwrap/pull/438): Simplify `Options` by
  removing generic type parameters.

  This change removes the new generic parameters introduced in version 0.14, as
  well as the original `WrapSplitter` parameter which has been present since
  very early versions.

  The result is a simplification of function and struct signatures across the
  board. So what used to be

  ```rust
  let options: Options<
      wrap_algorithms::FirstFit,
      word_separators::AsciiSpace,
      word_splitters::HyphenSplitter,
  > = Options::new(80);
  ```

  if types are fully written out, is now simply

  ```rust
  let options: Options<'_> = Options::new(80);
  ```

  The anonymous lifetime represent the lifetime of the `initial_indent` and
  `subsequent_indent` strings. The change is nearly performance neutral (a 1-2%
  regression).

Smaller improvements and changes:

- [#404](https://github.com/mgeisler/textwrap/pull/404): Make documentation for
  short last-line penalty more precise.
- [#405](https://github.com/mgeisler/textwrap/pull/405): Cleanup and simplify
  `Options` docstring.
- [#411](https://github.com/mgeisler/textwrap/pull/411): Default to `OptimalFit`
  in interactive example.
- [#415](https://github.com/mgeisler/textwrap/pull/415): Add demo program to
  help compute binary sizes.
- [#423](https://github.com/mgeisler/textwrap/pull/423): Add fuzz tests with
  fully arbitrary fragments.
- [#424](https://github.com/mgeisler/textwrap/pull/424): Change
  `wrap_optimal_fit` penalties to non-negative numbers.
- [#430](https://github.com/mgeisler/textwrap/pull/430): Add `debug-words`
  example.
- [#432](https://github.com/mgeisler/textwrap/pull/432): Use precise dependency
  versions in Cargo.toml.

## Version 0.14.2 (2021-06-27)

The 0.14.1 release included more changes than intended and has been yanked. The
change intended for 0.14.1 is now included in 0.14.2.

## Version 0.14.1 (2021-06-26)

This release fixes a panic reported by @Makoto, thanks!

- [#391](https://github.com/mgeisler/textwrap/pull/391): Fix panic in
  `find_words` due to string access outside of a character boundary.

## Version 0.14.0 (2021-06-05)

This is a major feature release which makes Textwrap more configurable and
flexible. The high-level API of `textwrap::wrap` and `textwrap::fill` remains
unchanged, but low-level structs have moved around.

The biggest change is the introduction of new generic type parameters to the
`Options` struct. These parameters lets you statically configure the wrapping
algorithm, the word separator, and the word splitter. If you previously spelled
out the full type for `Options`, you now need to take the extra type parameters
into account. This means that

```rust
let options: Options<HyphenSplitter> = Options::new(80);
```

changes to

```rust
let options: Options<
    wrap_algorithms::FirstFit,
    word_separators::AsciiSpace,
    word_splitters::HyphenSplitter,
> = Options::new(80);
```

This is quite a mouthful, so we suggest using type inference where possible. You
won’t see any chance if you call `wrap` directly with a width or with an
`Options` value constructed on the fly. Please open an issue if this causes
problems for you!

### New `WordSeparator` Trait

- [#332](https://github.com/mgeisler/textwrap/pull/332): Add `WordSeparator`
  trait to allow customizing how words are found in a line of text. Until now,
  Textwrap would always assume that words are separated by ASCII space
  characters. You can now customize this as needed.

- [#313](https://github.com/mgeisler/textwrap/pull/313): Add support for using
  the Unicode line breaking algorithm to find words. This is done by adding a
  second implementation of the new `WordSeparator` trait. The implementation
  uses the unicode-linebreak crate, which is a new optional dependency.

  With this, Textwrap can be used with East-Asian languages such as Chinese or
  Japanese where there are no spaces between words. Breaking a long sequence of
  emojis is another example where line breaks might be wanted even if there are
  no whitespace to be found. Feedback would be appreciated for this feature.

### Indent

- [#353](https://github.com/mgeisler/textwrap/pull/353): Trim trailing
  whitespace from `prefix` in `indent`.

  Before, empty lines would get no prefix added. Now, empty lines have a trimmed
  prefix added. This little trick makes `indent` much more useful since you can
  now safely indent with `"# "` without creating trailing whitespace in the
  output due to the trailing whitespace in your prefix.

- [#354](https://github.com/mgeisler/textwrap/pull/354): Make `indent` about 20%
  faster by preallocating the output string.

### Documentation

- [#308](https://github.com/mgeisler/textwrap/pull/308): Document handling of
  leading and trailing whitespace when wrapping text.

### WebAssembly Demo

- [#310](https://github.com/mgeisler/textwrap/pull/310): Thanks to WebAssembly,
  you can now try out Textwrap directly in your browser. Please try it out:
  https://mgeisler.github.io/textwrap/.

### New Generic Parameters

- [#331](https://github.com/mgeisler/textwrap/pull/331): Remove outer boxing
  from `Options`.

- [#357](https://github.com/mgeisler/textwrap/pull/357): Replace
  `core::WrapAlgorithm` enum with a `wrap_algorithms::WrapAlgorithm` trait. This
  allows for arbitrary wrapping algorithms to be plugged into the library.

- [#358](https://github.com/mgeisler/textwrap/pull/358): Switch wrapping
  functions to use a slice for `line_widths`.

- [#368](https://github.com/mgeisler/textwrap/pull/368): Move `WordSeparator`
  and `WordSplitter` traits to separate modules. Before, Textwrap had several
  top-level structs such as `NoHyphenation` and `HyphenSplitter`. These
  implementations of `WordSplitter` now lives in a dedicated `word_splitters`
  module. Similarly, we have a new `word_separators` module for implementations
  of `WordSeparator`.

- [#369](https://github.com/mgeisler/textwrap/pull/369): Rename
  `Options::splitter` to `Options::word_splitter` for consistency with the other
  fields backed by traits.

## Version 0.13.4 (2021-02-23)

This release removes `println!` statements which was left behind in `unfill` by
mistake.

- [#296](https://github.com/mgeisler/textwrap/pull/296): Improve house building
  example with more comments.
- [#297](https://github.com/mgeisler/textwrap/pull/297): Remove debug prints in
  the new `unfill` function.

## Version 0.13.3 (2021-02-20)

This release contains a bugfix for `indent` and improved handling of emojis.
We’ve also added a new function for formatting text in columns and functions for
reformatting already wrapped text.

- [#276](https://github.com/mgeisler/textwrap/pull/276): Extend
  `core::display_width` to handle emojis when the unicode-width Cargo feature is
  disabled.
- [#279](https://github.com/mgeisler/textwrap/pull/279): Make `indent` preserve
  existing newlines in the input string. Before, `indent("foo", "")` would
  return `"foo\n"` by mistake. It now returns `"foo"` instead.
- [#281](https://github.com/mgeisler/textwrap/pull/281): Ensure all `Options`
  fields have examples.
- [#282](https://github.com/mgeisler/textwrap/pull/282): Add a `wrap_columns`
  function.
- [#294](https://github.com/mgeisler/textwrap/pull/294): Add new `unfill` and
  `refill` functions.

## Version 0.13.2 (2020-12-30)

This release primarily makes all dependencies optional. This makes it possible
to slim down textwrap as needed.

- [#254](https://github.com/mgeisler/textwrap/pull/254): `impl WordSplitter` for
  `Box<T> where T: WordSplitter`.
- [#255](https://github.com/mgeisler/textwrap/pull/255): Use command line
  arguments as initial text in interactive example.
- [#256](https://github.com/mgeisler/textwrap/pull/256): Introduce fuzz tests
  for `wrap_optimal_fit` and `wrap_first_fit`.
- [#260](https://github.com/mgeisler/textwrap/pull/260): Make the unicode-width
  dependency optional.
- [#261](https://github.com/mgeisler/textwrap/pull/261): Make the smawk
  dependency optional.

## Version 0.13.1 (2020-12-10)

This is a bugfix release which fixes a regression in 0.13.0. The bug meant that
colored text was wrapped incorrectly.

- [#245](https://github.com/mgeisler/textwrap/pull/245): Support deleting a word
  with Ctrl-Backspace in the interactive demo.
- [#246](https://github.com/mgeisler/textwrap/pull/246): Show build type
  (debug/release) in interactive demo.
- [#249](https://github.com/mgeisler/textwrap/pull/249): Correctly compute width
  while skipping over ANSI escape sequences.

## Version 0.13.0 (2020-12-05)

This is a major release which rewrites the core logic, adds many new features,
and fixes a couple of bugs. Most programs which use `textwrap` stays the same,
incompatibilities and upgrade notes are given below.

Clone the repository and run the following to explore the new features in an
interactive demo (Linux only):

```sh
$ cargo run --example interactive --all-features
```

### Bug Fixes

#### Rewritten core wrapping algorithm

- [#221](https://github.com/mgeisler/textwrap/pull/221): Reformulate wrapping in
  terms of words with whitespace and penalties.

The core wrapping algorithm has been completely rewritten. This fixed bugs and
simplified the code, while also making it possible to use `textwrap` outside the
context of the terminal.

As part of this, trailing whitespace is now discarded consistently from wrapped
lines. Before we would inconsistently remove whitespace at the end of wrapped
lines, except for the last. Leading whitespace is still preserved.

### New Features

#### Optimal-fit wrapping

- [#234](https://github.com/mgeisler/textwrap/pull/234): Introduce wrapping
  using an optimal-fit algorithm.

This release adds support for new wrapping algorithm which finds a globally
optimal set of line breaks, taking certain penalties into account. As an
example, the old algorithm would produce

    "To be, or"
    "not to be:"
    "that is"
    "the"
    "question"

Notice how the fourth line with “the” is very short. The new algorithm shortens
the previous lines slightly to produce fewer short lines:

    "To be,"
    "or not to"
    "be: that"
    "is the"
    "question"

Use the new `textwrap::core::WrapAlgorithm` enum to select between the new and
old algorithm. By default, the new algorithm is used.

The optimal-fit algorithm is inspired by the line breaking algorithm used in
TeX, described in the 1981 article
[_Breaking Paragraphs into Lines_](http://www.eprg.org/G53DOC/pdfs/knuth-plass-breaking.pdf)
by Knuth and Plass.

#### In-place wrapping

- [#226](https://github.com/mgeisler/textwrap/pull/226): Add a `fill_inplace`
  function.

When the text you want to fill is already a temporary `String`, you can now
mutate it in-place with `fill_inplace`:

```rust
let mut greeting = format!("Greetings {}, welcome to the game! You have {} lives left.",
                           player.name, player.lives);
fill_inplace(&mut greeting, line_width);
```

This is faster than calling `fill` and it will reuse the memory already
allocated for the string.

### Changed Features

#### `Wrapper` is replaced with `Options`

- [#213](https://github.com/mgeisler/textwrap/pull/213): Simplify API with only
  top-level functions.
- [#215](https://github.com/mgeisler/textwrap/pull/215): Reintroducing the type
  parameter on `Options` (previously known as `Wrapper`).
- [#219](https://github.com/mgeisler/textwrap/pull/219): Allow using trait
  objects with `fill` & `wrap`.
- [#227](https://github.com/mgeisler/textwrap/pull/227): Replace `WrapOptions`
  with `Into<Options>`.

The `Wrapper` struct held the options (line width, indentation, etc) for
wrapping text. It was also the entry point for actually wrapping the text via
its methods such as `wrap`, `wrap_iter`, `into_wrap_iter`, and `fill` methods.

The struct has been replaced by a simpler `Options` struct which only holds
options. The `Wrapper` methods are gone, their job has been taken over by the
top-level `wrap` and `fill` functions. The signature of these functions have
changed from

```rust
fn fill(s: &str, width: usize) -> String;

fn wrap(s: &str, width: usize) -> Vec<Cow<'_, str>>;
```

to the more general

```rust
fn fill<'a, S, Opt>(text: &str, options: Opt) -> String
where
    S: WordSplitter,
    Opt: Into<Options<'a, S>>;

fn wrap<'a, S, Opt>(text: &str, options: Opt) -> Vec<Cow<'_, str>>
where
    S: WordSplitter,
    Opt: Into<Options<'a, S>>;
```

The `Into<Options<'a, S>` bound allows you to pass an `usize` (which is
interpreted as the line width) _and_ a full `Options` object. This allows the
new functions to work like the old, plus you can now fully customize the
behavior of the wrapping via `Options` when needed.

Code that call `textwrap::wrap` or `textwrap::fill` can remain unchanged. Code
that calls into `Wrapper::wrap` or `Wrapper::fill` will need to be update. This
is a mechanical change, please see
[#213](https://github.com/mgeisler/textwrap/pull/213) for examples.

Thanks to @CryptJar and @Koxiat for their support in the PRs above!

### Removed Features

- The `wrap_iter` and `into_wrap_iter` methods are gone. This means that lazy
  iteration is no longer supported: you always get all wrapped lines back as a
  `Vec`. This was done to simplify the code and to support the optimal-fit
  algorithm.

  The first-fit algorithm could still be implemented in an incremental fashion.
  Please let us know if this is important to you.

### Other Changes

- [#206](https://github.com/mgeisler/textwrap/pull/206): Change
  `Wrapper.splitter` from `T: WordSplitter` to `Box<dyn WordSplitter>`.
- [#216](https://github.com/mgeisler/textwrap/pull/216): Forbid the use of
  unsafe code.

## Version 0.12.1 (2020-07-03)

This is a bugfix release.

- Fixed [#176][issue-176]: Mention compile-time wrapping by linking to the
  [`textwrap-macros` crate].
- Fixed [#193][issue-193]: Wrapping with `break_words(false)` was broken and
  would cause extra whitespace to be inserted when words were longer than the
  line width.

## Version 0.12.0 (2020-06-26)

The code has been updated to the [Rust 2018 edition][rust-2018] and each new
release of `textwrap` will only support the latest stable version of Rust.
Trying to support older Rust versions is a fool's errand: our dependencies keep
releasing new patch versions that require newer and newer versions of Rust.

The `term_size` feature has been replaced by `terminal_size`. The API is
unchanged, it is just the name of the Cargo feature that changed.

The `hyphenation` feature now only embeds the hyphenation patterns for
US-English. This slims down the dependency.

- Fixed [#140][issue-140]: Ignore ANSI escape sequences.
- Fixed [#158][issue-158]: Unintended wrapping when using external splitter.
- Fixed [#177][issue-177]: Update examples to the 2018 edition.

## Version 0.11.0 (2018-12-09)

Due to our dependencies bumping their minimum supported version of Rust, the
minimum version of Rust we test against is now 1.22.0.

- Merged [#141][issue-141]: Fix `dedent` handling of empty lines and trailing
  newlines. Thanks @bbqsrc!
- Fixed [#151][issue-151]: Release of version with hyphenation 0.7.

## Version 0.10.0 (2018-04-28)

Due to our dependencies bumping their minimum supported version of Rust, the
minimum version of Rust we test against is now 1.17.0.

- Fixed [#99][issue-99]: Word broken even though it would fit on line.
- Fixed [#107][issue-107]: Automatic hyphenation is off by one.
- Fixed [#122][issue-122]: Take newlines into account when wrapping.
- Fixed [#129][issue-129]: Panic on string with em-dash.

## Version 0.9.0 (2017-10-05)

The dependency on `term_size` is now optional, and by default this feature is
not enabled. This is a _breaking change_ for users of `Wrapper::with_termwidth`.
Enable the `term_size` feature to restore the old functionality.

Added a regression test for the case where `width` is set to `usize::MAX`,
thanks @Fraser999! All public structs now implement `Debug`, thanks @hcpl!

- Fixed [#101][issue-101]: Make `term_size` an optional dependency.

## Version 0.8.0 (2017-09-04)

The `Wrapper` struct is now generic over the type of word splitter being used.
This means less boxing and a nicer API. The `Wrapper::word_splitter` method has
been removed. This is a _breaking API change_ if you used the method to change
the word splitter.

The `Wrapper` struct has two new methods that will wrap the input text lazily:
`Wrapper::wrap_iter` and `Wrapper::into_wrap_iter`. Use those if you will be
iterating over the wrapped lines one by one.

- Fixed [#59][issue-59]: `wrap` could return an iterator. Thanks @hcpl!
- Fixed [#81][issue-81]: Set `html_root_url`.

## Version 0.7.0 (2017-07-20)

Version 0.7.0 changes the return type of `Wrapper::wrap` from `Vec<String>` to
`Vec<Cow<'a, str>>`. This means that the output lines borrow data from the input
string. This is a _breaking API change_ if you relied on the exact return type
of `Wrapper::wrap`. Callers of the `textwrap::fill` convenience function will
see no breakage.

The above change and other optimizations makes version 0.7.0 roughly 15-30%
faster than version 0.6.0.

The `squeeze_whitespace` option has been removed since it was complicating the
above optimization. Let us know if this option is important for you so we can
provide a work around.

- Fixed [#58][issue-58]: Add a "fast_wrap" function.
- Fixed [#61][issue-61]: Documentation errors.

## Version 0.6.0 (2017-05-22)

Version 0.6.0 adds builder methods to `Wrapper` for easy one-line initialization
and configuration:

```rust
let wrapper = Wrapper::new(60).break_words(false);
```

It also add a new `NoHyphenation` word splitter that will never split words, not
even at existing hyphens.

- Fixed [#28][issue-28]: Support not squeezing whitespace.

## Version 0.5.0 (2017-05-15)

Version 0.5.0 has _breaking API changes_. However, this only affects code using
the hyphenation feature. The feature is now optional, so you will first need to
enable the `hyphenation` feature as described above. Afterwards, please change
your code from

```rust
wrapper.corpus = Some(&corpus);
```

to

```rust
wrapper.splitter = Box::new(corpus);
```

Other changes include optimizations, so version 0.5.0 is roughly 10-15% faster
than version 0.4.0.

- Fixed [#19][issue-19]: Add support for finding terminal size.
- Fixed [#25][issue-25]: Handle words longer than `self.width`.
- Fixed [#26][issue-26]: Support custom indentation.
- Fixed [#36][issue-36]: Support building without `hyphenation`.
- Fixed [#39][issue-39]: Respect non-breaking spaces.

## Version 0.4.0 (2017-01-24)

Documented complexities and tested these via `cargo bench`.

- Fixed [#13][issue-13]: Immediately add word if it fits.
- Fixed [#14][issue-14]: Avoid splitting on initial hyphens.

## Version 0.3.0 (2017-01-07)

Added support for automatic hyphenation.

## Version 0.2.0 (2016-12-28)

Introduced `Wrapper` struct. Added support for wrapping on hyphens.

## Version 0.1.0 (2016-12-17)

First public release with support for wrapping strings on whitespace.

[rust-2018]: https://doc.rust-lang.org/edition-guide/rust-2018/
[`textwrap-macros` crate]: https://crates.io/crates/textwrap-macros
[issue-13]: https://github.com/mgeisler/textwrap/issues/13
[issue-14]: https://github.com/mgeisler/textwrap/issues/14
[issue-19]: https://github.com/mgeisler/textwrap/issues/19
[issue-25]: https://github.com/mgeisler/textwrap/issues/25
[issue-26]: https://github.com/mgeisler/textwrap/issues/26
[issue-28]: https://github.com/mgeisler/textwrap/issues/28
[issue-36]: https://github.com/mgeisler/textwrap/issues/36
[issue-39]: https://github.com/mgeisler/textwrap/issues/39
[issue-58]: https://github.com/mgeisler/textwrap/issues/58
[issue-59]: https://github.com/mgeisler/textwrap/issues/59
[issue-61]: https://github.com/mgeisler/textwrap/issues/61
[issue-81]: https://github.com/mgeisler/textwrap/issues/81
[issue-99]: https://github.com/mgeisler/textwrap/issues/99
[issue-101]: https://github.com/mgeisler/textwrap/issues/101
[issue-107]: https://github.com/mgeisler/textwrap/issues/107
[issue-122]: https://github.com/mgeisler/textwrap/issues/122
[issue-129]: https://github.com/mgeisler/textwrap/issues/129
[issue-140]: https://github.com/mgeisler/textwrap/issues/140
[issue-141]: https://github.com/mgeisler/textwrap/issues/141
[issue-151]: https://github.com/mgeisler/textwrap/issues/151
[issue-158]: https://github.com/mgeisler/textwrap/issues/158
[issue-176]: https://github.com/mgeisler/textwrap/issues/176
[issue-177]: https://github.com/mgeisler/textwrap/issues/177
[issue-193]: https://github.com/mgeisler/textwrap/issues/193