//! The textwrap library provides functions for word wrapping and
//! indenting text.
//!
//! # Wrapping Text
//!
//! Wrapping text can be very useful in command-line programs where
//! you want to format dynamic output nicely so it looks good in a
//! terminal. A quick example:
//!
//! ```
//! # #[cfg(feature = "smawk")] {
//! let text = "textwrap: a small library for wrapping text.";
//! assert_eq!(textwrap::wrap(text, 18),
//! vec!["textwrap: a",
//! "small library for",
//! "wrapping text."]);
//! # }
//! ```
//!
//! The [`wrap`] function returns the individual lines, use [`fill`]
//! is you want the lines joined with `'\n'` to form a `String`.
//!
//! If you enable the `hyphenation` Cargo feature, you can get
//! automatic hyphenation for a number of languages:
//!
//! ```
//! #[cfg(feature = "hyphenation")] {
//! use hyphenation::{Language, Load, Standard};
//! use textwrap::{wrap, Options, WordSplitter};
//!
//! let text = "textwrap: a small library for wrapping text.";
//! let dictionary = Standard::from_embedded(Language::EnglishUS).unwrap();
//! let options = Options::new(18).word_splitter(WordSplitter::Hyphenation(dictionary));
//! assert_eq!(wrap(text, &options),
//! vec!["textwrap: a small",
//! "library for wrap-",
//! "ping text."]);
//! }
//! ```
//!
//! See also the [`unfill`] and [`refill`] functions which allow you to
//! manipulate already wrapped text.
//!
//! ## Wrapping Strings at Compile Time
//!
//! If your strings are known at compile time, please take a look at
//! the procedural macros from the [textwrap-macros] crate.
//!
//! ## Displayed Width vs Byte Size
//!
//! To word wrap text, one must know the width of each word so one can
//! know when to break lines. This library will by default measure the
//! width of text using the _displayed width_, not the size in bytes.
//! The `unicode-width` Cargo feature controls this.
//!
//! This is important for non-ASCII text. ASCII characters such as `a`
//! and `!` are simple and take up one column each. This means that
//! the displayed width is equal to the string length in bytes.
//! However, non-ASCII characters and symbols take up more than one
//! byte when UTF-8 encoded: `é` is `0xc3 0xa9` (two bytes) and `⚙` is
//! `0xe2 0x9a 0x99` (three bytes) in UTF-8, respectively.
//!
//! This is why we take care to use the displayed width instead of the
//! byte count when computing line lengths. All functions in this
//! library handle Unicode characters like this when the
//! `unicode-width` Cargo feature is enabled (it is enabled by
//! default).
//!
//! # Indentation and Dedentation
//!
//! The textwrap library also offers functions for adding a prefix to
//! every line of a string and to remove leading whitespace. As an
//! example, the [`indent`] function allows you to turn lines of text
//! into a bullet list:
//!
//! ```
//! let before = "\
//! foo
//! bar
//! baz
//! ";
//! let after = "\
//! * foo
//! * bar
//! * baz
//! ";
//! assert_eq!(textwrap::indent(before, "* "), after);
//! ```
//!
//! Removing leading whitespace is done with [`dedent`]:
//!
//! ```
//! let before = "
//! Some
//! indented
//! text
//! ";
//! let after = "
//! Some
//! indented
//! text
//! ";
//! assert_eq!(textwrap::dedent(before), after);
//! ```
//!
//! # Cargo Features
//!
//! The textwrap library can be slimmed down as needed via a number of
//! Cargo features. This means you only pay for the features you
//! actually use.
//!
//! The full dependency graph, where dashed lines indicate optional
//! dependencies, is shown below:
//!
//! 
//!
//! ## Default Features
//!
//! These features are enabled by default:
//!
//! * `unicode-linebreak`: enables finding words using the
//! [unicode-linebreak] crate, which implements the line breaking
//! algorithm described in [Unicode Standard Annex
//! #14](https://www.unicode.org/reports/tr14/).
//!
//! This feature can be disabled if you are happy to find words
//! separated by ASCII space characters only. People wrapping text
//! with emojis or East-Asian characters will want most likely want
//! to enable this feature. See [`WordSeparator`] for details.
//!
//! * `unicode-width`: enables correct width computation of non-ASCII
//! characters via the [unicode-width] crate. Without this feature,
//! every [`char`] is 1 column wide, except for emojis which are 2
//! columns wide. See the [`core::display_width`] function for
//! details.
//!
//! This feature can be disabled if you only need to wrap ASCII
//! text, or if the functions in [`core`] are used directly with
//! [`core::Fragment`]s for which the widths have been computed in
//! other ways.
//!
//! * `smawk`: enables linear-time wrapping of the whole paragraph via
//! the [smawk] crate. See the [`wrap_algorithms::wrap_optimal_fit`]
//! function for details on the optimal-fit algorithm.
//!
//! This feature can be disabled if you only ever intend to use
//! [`wrap_algorithms::wrap_first_fit`].
//!
//! With Rust 1.59.0, the size impact of the above features on your
//! binary is as follows:
//!
//! | Configuration | Binary Size | Delta |
//! | :--- | ---: | ---: |
//! | quick-and-dirty implementation | 289 KB | — KB |
//! | textwrap without default features | 301 KB | 12 KB |
//! | textwrap with smawk | 317 KB | 28 KB |
//! | textwrap with unicode-width | 313 KB | 24 KB |
//! | textwrap with unicode-linebreak | 395 KB | 106 KB |
//!
//! The above sizes are the stripped sizes and the binary is compiled
//! in release mode with this profile:
//!
//! ```toml
//! [profile.release]
//! lto = true
//! codegen-units = 1
//! ```
//!
//! See the [binary-sizes demo] if you want to reproduce these
//! results.
//!
//! ## Optional Features
//!
//! These Cargo features enable new functionality:
//!
//! * `terminal_size`: enables automatic detection of the terminal
//! width via the [terminal_size] crate. See the
//! [`Options::with_termwidth`] constructor for details.
//!
//! * `hyphenation`: enables language-sensitive hyphenation via the
//! [hyphenation] crate. See the [`word_splitters::WordSplitter`]
//! trait for details.
//!
//! [unicode-linebreak]: https://docs.rs/unicode-linebreak/
//! [unicode-width]: https://docs.rs/unicode-width/
//! [smawk]: https://docs.rs/smawk/
//! [binary-sizes demo]: https://github.com/mgeisler/textwrap/tree/master/examples/binary-sizes
//! [textwrap-macros]: https://docs.rs/textwrap-macros/
//! [terminal_size]: https://docs.rs/terminal_size/
//! [hyphenation]: https://docs.rs/hyphenation/
#![doc(html_root_url = "https://docs.rs/textwrap/0.15.0")]
#![forbid(unsafe_code)] // See https://github.com/mgeisler/textwrap/issues/210
#![deny(missing_docs)]
#![deny(missing_debug_implementations)]
#![allow(clippy::redundant_field_names)]
// Make `cargo test` execute the README doctests.
#[cfg(doctest)]
#[doc = include_str!("../README.md")]
mod readme_doctest {}
use std::borrow::Cow;
mod indentation;
pub use crate::indentation::{dedent, indent};
mod word_separators;
pub use word_separators::WordSeparator;
pub mod word_splitters;
pub use word_splitters::WordSplitter;
pub mod wrap_algorithms;
pub use wrap_algorithms::WrapAlgorithm;
pub mod core;
#[cfg(feature = "unicode-linebreak")]
macro_rules! DefaultWordSeparator {
() => {
WordSeparator::UnicodeBreakProperties
};
}
#[cfg(not(feature = "unicode-linebreak"))]
macro_rules! DefaultWordSeparator {
() => {
WordSeparator::AsciiSpace
};
}
/// Holds configuration options for wrapping and filling text.
#[derive(Debug, Clone)]
pub struct Options<'a> {
/// The width in columns at which the text will be wrapped.
pub width: usize,
/// Indentation used for the first line of output. See the
/// [`Options::initial_indent`] method.
pub initial_indent: &'a str,
/// Indentation used for subsequent lines of output. See the
/// [`Options::subsequent_indent`] method.
pub subsequent_indent: &'a str,
/// Allow long words to be broken if they cannot fit on a line.
/// When set to `false`, some lines may be longer than
/// `self.width`. See the [`Options::break_words`] method.
pub break_words: bool,
/// Wrapping algorithm to use, see the implementations of the
/// [`wrap_algorithms::WrapAlgorithm`] trait for details.
pub wrap_algorithm: WrapAlgorithm,
/// The line breaking algorithm to use, see
/// [`word_separators::WordSeparator`] trait for an overview and
/// possible implementations.
pub word_separator: WordSeparator,
/// The method for splitting words. This can be used to prohibit
/// splitting words on hyphens, or it can be used to implement
/// language-aware machine hyphenation.
pub word_splitter: WordSplitter,
}
impl<'a> From<&'a Options<'a>> for Options<'a> {
fn from(options: &'a Options<'a>) -> Self {
Self {
width: options.width,
initial_indent: options.initial_indent,
subsequent_indent: options.subsequent_indent,
break_words: options.break_words,
word_separator: options.word_separator,
wrap_algorithm: options.wrap_algorithm,
word_splitter: options.word_splitter.clone(),
}
}
}
impl<'a> From for Options<'a> {
fn from(width: usize) -> Self {
Options::new(width)
}
}
impl<'a> Options<'a> {
/// Creates a new [`Options`] with the specified width. Equivalent to
///
/// ```
/// # use textwrap::{Options, WordSplitter, WordSeparator, WrapAlgorithm};
/// # let width = 80;
/// # let actual = Options::new(width);
/// # let expected =
/// Options {
/// width: width,
/// initial_indent: "",
/// subsequent_indent: "",
/// break_words: true,
/// #[cfg(feature = "unicode-linebreak")]
/// word_separator: WordSeparator::UnicodeBreakProperties,
/// #[cfg(not(feature = "unicode-linebreak"))]
/// word_separator: WordSeparator::AsciiSpace,
/// #[cfg(feature = "smawk")]
/// wrap_algorithm: WrapAlgorithm::new_optimal_fit(),
/// #[cfg(not(feature = "smawk"))]
/// wrap_algorithm: WrapAlgorithm::FirstFit,
/// word_splitter: WordSplitter::HyphenSplitter,
/// }
/// # ;
/// # assert_eq!(actual.width, expected.width);
/// # assert_eq!(actual.initial_indent, expected.initial_indent);
/// # assert_eq!(actual.subsequent_indent, expected.subsequent_indent);
/// # assert_eq!(actual.break_words, expected.break_words);
/// # assert_eq!(actual.word_splitter, expected.word_splitter);
/// ```
///
/// Note that the default word separator and wrap algorithms
/// changes based on the available Cargo features. The best
/// available algorithms are used by default.
pub const fn new(width: usize) -> Self {
Options {
width,
initial_indent: "",
subsequent_indent: "",
break_words: true,
word_separator: DefaultWordSeparator!(),
wrap_algorithm: WrapAlgorithm::new(),
word_splitter: WordSplitter::HyphenSplitter,
}
}
/// Creates a new [`Options`] with `width` set to the current
/// terminal width. If the terminal width cannot be determined
/// (typically because the standard input and output is not
/// connected to a terminal), a width of 80 characters will be
/// used. Other settings use the same defaults as
/// [`Options::new`].
///
/// Equivalent to:
///
/// ```no_run
/// use textwrap::{termwidth, Options};
///
/// let options = Options::new(termwidth());
/// ```
///
/// **Note:** Only available when the `terminal_size` feature is
/// enabled.
#[cfg(feature = "terminal_size")]
pub fn with_termwidth() -> Self {
Self::new(termwidth())
}
}
impl<'a> Options<'a> {
/// Change [`self.initial_indent`]. The initial indentation is
/// used on the very first line of output.
///
/// # Examples
///
/// Classic paragraph indentation can be achieved by specifying an
/// initial indentation and wrapping each paragraph by itself:
///
/// ```
/// use textwrap::{wrap, Options};
///
/// let options = Options::new(16).initial_indent(" ");
/// assert_eq!(wrap("This is a little example.", options),
/// vec![" This is a",
/// "little example."]);
/// ```
///
/// [`self.initial_indent`]: #structfield.initial_indent
pub fn initial_indent(self, indent: &'a str) -> Self {
Options {
initial_indent: indent,
..self
}
}
/// Change [`self.subsequent_indent`]. The subsequent indentation
/// is used on lines following the first line of output.
///
/// # Examples
///
/// Combining initial and subsequent indentation lets you format a
/// single paragraph as a bullet list:
///
/// ```
/// use textwrap::{wrap, Options};
///
/// let options = Options::new(12)
/// .initial_indent("* ")
/// .subsequent_indent(" ");
/// #[cfg(feature = "smawk")]
/// assert_eq!(wrap("This is a little example.", options),
/// vec!["* This is",
/// " a little",
/// " example."]);
///
/// // Without the `smawk` feature, the wrapping is a little different:
/// #[cfg(not(feature = "smawk"))]
/// assert_eq!(wrap("This is a little example.", options),
/// vec!["* This is a",
/// " little",
/// " example."]);
/// ```
///
/// [`self.subsequent_indent`]: #structfield.subsequent_indent
pub fn subsequent_indent(self, indent: &'a str) -> Self {
Options {
subsequent_indent: indent,
..self
}
}
/// Change [`self.break_words`]. This controls if words longer
/// than `self.width` can be broken, or if they will be left
/// sticking out into the right margin.
///
/// # Examples
///
/// ```
/// use textwrap::{wrap, Options};
///
/// let options = Options::new(4).break_words(true);
/// assert_eq!(wrap("This is a little example.", options),
/// vec!["This",
/// "is a",
/// "litt",
/// "le",
/// "exam",
/// "ple."]);
/// ```
///
/// [`self.break_words`]: #structfield.break_words
pub fn break_words(self, setting: bool) -> Self {
Options {
break_words: setting,
..self
}
}
/// Change [`self.word_separator`].
///
/// See [`word_separators::WordSeparator`] for details on the choices.
///
/// [`self.word_separator`]: #structfield.word_separator
pub fn word_separator(self, word_separator: WordSeparator) -> Options<'a> {
Options {
width: self.width,
initial_indent: self.initial_indent,
subsequent_indent: self.subsequent_indent,
break_words: self.break_words,
word_separator: word_separator,
wrap_algorithm: self.wrap_algorithm,
word_splitter: self.word_splitter,
}
}
/// Change [`self.wrap_algorithm`].
///
/// See the [`wrap_algorithms::WrapAlgorithm`] trait for details on
/// the choices.
///
/// [`self.wrap_algorithm`]: #structfield.wrap_algorithm
pub fn wrap_algorithm(self, wrap_algorithm: WrapAlgorithm) -> Options<'a> {
Options {
width: self.width,
initial_indent: self.initial_indent,
subsequent_indent: self.subsequent_indent,
break_words: self.break_words,
word_separator: self.word_separator,
wrap_algorithm: wrap_algorithm,
word_splitter: self.word_splitter,
}
}
/// Change [`self.word_splitter`]. The
/// [`word_splitters::WordSplitter`] is used to fit part of a word
/// into the current line when wrapping text.
///
/// # Examples
///
/// ```
/// use textwrap::{Options, WordSplitter};
/// let opt = Options::new(80);
/// assert_eq!(opt.word_splitter, WordSplitter::HyphenSplitter);
/// let opt = opt.word_splitter(WordSplitter::NoHyphenation);
/// assert_eq!(opt.word_splitter, WordSplitter::NoHyphenation);
/// ```
///
/// [`self.word_splitter`]: #structfield.word_splitter
pub fn word_splitter(self, word_splitter: WordSplitter) -> Options<'a> {
Options {
width: self.width,
initial_indent: self.initial_indent,
subsequent_indent: self.subsequent_indent,
break_words: self.break_words,
word_separator: self.word_separator,
wrap_algorithm: self.wrap_algorithm,
word_splitter,
}
}
}
/// Return the current terminal width.
///
/// If the terminal width cannot be determined (typically because the
/// standard output is not connected to a terminal), a default width
/// of 80 characters will be used.
///
/// # Examples
///
/// Create an [`Options`] for wrapping at the current terminal width
/// with a two column margin to the left and the right:
///
/// ```no_run
/// use textwrap::{termwidth, Options};
///
/// let width = termwidth() - 4; // Two columns on each side.
/// let options = Options::new(width)
/// .initial_indent(" ")
/// .subsequent_indent(" ");
/// ```
///
/// **Note:** Only available when the `terminal_size` Cargo feature is
/// enabled.
#[cfg(feature = "terminal_size")]
pub fn termwidth() -> usize {
terminal_size::terminal_size().map_or(80, |(terminal_size::Width(w), _)| w.into())
}
/// Fill a line of text at a given width.
///
/// The result is a [`String`], complete with newlines between each
/// line. Use the [`wrap`] function if you need access to the
/// individual lines.
///
/// The easiest way to use this function is to pass an integer for
/// `width_or_options`:
///
/// ```
/// use textwrap::fill;
///
/// assert_eq!(
/// fill("Memory safety without garbage collection.", 15),
/// "Memory safety\nwithout garbage\ncollection."
/// );
/// ```
///
/// If you need to customize the wrapping, you can pass an [`Options`]
/// instead of an `usize`:
///
/// ```
/// use textwrap::{fill, Options};
///
/// let options = Options::new(15)
/// .initial_indent("- ")
/// .subsequent_indent(" ");
/// assert_eq!(
/// fill("Memory safety without garbage collection.", &options),
/// "- Memory safety\n without\n garbage\n collection."
/// );
/// ```
pub fn fill<'a, Opt>(text: &str, width_or_options: Opt) -> String
where
Opt: Into>,
{
// This will avoid reallocation in simple cases (no
// indentation, no hyphenation).
let mut result = String::with_capacity(text.len());
for (i, line) in wrap(text, width_or_options).iter().enumerate() {
if i > 0 {
result.push('\n');
}
result.push_str(line);
}
result
}
/// Unpack a paragraph of already-wrapped text.
///
/// This function attempts to recover the original text from a single
/// paragraph of text produced by the [`fill`] function. This means
/// that it turns
///
/// ```text
/// textwrap: a small
/// library for
/// wrapping text.
/// ```
///
/// back into
///
/// ```text
/// textwrap: a small library for wrapping text.
/// ```
///
/// In addition, it will recognize a common prefix among the lines.
/// The prefix of the first line is returned in
/// [`Options::initial_indent`] and the prefix (if any) of the the
/// other lines is returned in [`Options::subsequent_indent`].
///
/// In addition to `' '`, the prefixes can consist of characters used
/// for unordered lists (`'-'`, `'+'`, and `'*'`) and block quotes
/// (`'>'`) in Markdown as well as characters often used for inline
/// comments (`'#'` and `'/'`).
///
/// The text must come from a single wrapped paragraph. This means
/// that there can be no `"\n\n"` within the text.
///
/// # Examples
///
/// ```
/// use textwrap::unfill;
///
/// let (text, options) = unfill("\
/// * This is an
/// example of
/// a list item.
/// ");
///
/// assert_eq!(text, "This is an example of a list item.\n");
/// assert_eq!(options.initial_indent, "* ");
/// assert_eq!(options.subsequent_indent, " ");
/// ```
pub fn unfill(text: &str) -> (String, Options<'_>) {
let trimmed = text.trim_end_matches('\n');
let prefix_chars: &[_] = &[' ', '-', '+', '*', '>', '#', '/'];
let mut options = Options::new(0);
for (idx, line) in trimmed.split('\n').enumerate() {
options.width = std::cmp::max(options.width, core::display_width(line));
let without_prefix = line.trim_start_matches(prefix_chars);
let prefix = &line[..line.len() - without_prefix.len()];
if idx == 0 {
options.initial_indent = prefix;
} else if idx == 1 {
options.subsequent_indent = prefix;
} else if idx > 1 {
for ((idx, x), y) in prefix.char_indices().zip(options.subsequent_indent.chars()) {
if x != y {
options.subsequent_indent = &prefix[..idx];
break;
}
}
if prefix.len() < options.subsequent_indent.len() {
options.subsequent_indent = prefix;
}
}
}
let mut unfilled = String::with_capacity(text.len());
for (idx, line) in trimmed.split('\n').enumerate() {
if idx == 0 {
unfilled.push_str(&line[options.initial_indent.len()..]);
} else {
unfilled.push(' ');
unfilled.push_str(&line[options.subsequent_indent.len()..]);
}
}
unfilled.push_str(&text[trimmed.len()..]);
(unfilled, options)
}
/// Refill a paragraph of wrapped text with a new width.
///
/// This function will first use the [`unfill`] function to remove
/// newlines from the text. Afterwards the text is filled again using
/// the [`fill`] function.
///
/// The `new_width_or_options` argument specify the new width and can
/// specify other options as well — except for
/// [`Options::initial_indent`] and [`Options::subsequent_indent`],
/// which are deduced from `filled_text`.
///
/// # Examples
///
/// ```
/// use textwrap::refill;
///
/// // Some loosely wrapped text. The "> " prefix is recognized automatically.
/// let text = "\
/// > Memory
/// > safety without garbage
/// > collection.
/// ";
///
/// assert_eq!(refill(text, 20), "\
/// > Memory safety
/// > without garbage
/// > collection.
/// ");
///
/// assert_eq!(refill(text, 40), "\
/// > Memory safety without garbage
/// > collection.
/// ");
///
/// assert_eq!(refill(text, 60), "\
/// > Memory safety without garbage collection.
/// ");
/// ```
///
/// You can also reshape bullet points:
///
/// ```
/// use textwrap::refill;
///
/// let text = "\
/// - This is my
/// list item.
/// ";
///
/// assert_eq!(refill(text, 20), "\
/// - This is my list
/// item.
/// ");
/// ```
pub fn refill<'a, Opt>(filled_text: &str, new_width_or_options: Opt) -> String
where
Opt: Into>,
{
let trimmed = filled_text.trim_end_matches('\n');
let (text, options) = unfill(trimmed);
let mut new_options = new_width_or_options.into();
new_options.initial_indent = options.initial_indent;
new_options.subsequent_indent = options.subsequent_indent;
let mut refilled = fill(&text, new_options);
refilled.push_str(&filled_text[trimmed.len()..]);
refilled
}
/// Wrap a line of text at a given width.
///
/// The result is a vector of lines, each line is of type [`Cow<'_,
/// str>`](Cow), which means that the line will borrow from the input
/// `&str` if possible. The lines do not have trailing whitespace,
/// including a final `'\n'`. Please use the [`fill`] function if you
/// need a [`String`] instead.
///
/// The easiest way to use this function is to pass an integer for
/// `width_or_options`:
///
/// ```
/// use textwrap::wrap;
///
/// let lines = wrap("Memory safety without garbage collection.", 15);
/// assert_eq!(lines, &[
/// "Memory safety",
/// "without garbage",
/// "collection.",
/// ]);
/// ```
///
/// If you need to customize the wrapping, you can pass an [`Options`]
/// instead of an `usize`:
///
/// ```
/// use textwrap::{wrap, Options};
///
/// let options = Options::new(15)
/// .initial_indent("- ")
/// .subsequent_indent(" ");
/// let lines = wrap("Memory safety without garbage collection.", &options);
/// assert_eq!(lines, &[
/// "- Memory safety",
/// " without",
/// " garbage",
/// " collection.",
/// ]);
/// ```
///
/// # Optimal-Fit Wrapping
///
/// By default, `wrap` will try to ensure an even right margin by
/// finding breaks which avoid short lines. We call this an
/// “optimal-fit algorithm” since the line breaks are computed by
/// considering all possible line breaks. The alternative is a
/// “first-fit algorithm” which simply accumulates words until they no
/// longer fit on the line.
///
/// As an example, using the first-fit algorithm to wrap the famous
/// Hamlet quote “To be, or not to be: that is the question” in a
/// narrow column with room for only 10 characters looks like this:
///
/// ```
/// # use textwrap::{WrapAlgorithm::FirstFit, Options, wrap};
/// #
/// # let lines = wrap("To be, or not to be: that is the question",
/// # Options::new(10).wrap_algorithm(FirstFit));
/// # assert_eq!(lines.join("\n") + "\n", "\
/// To be, or
/// not to be:
/// that is
/// the
/// question
/// # ");
/// ```
///
/// Notice how the second to last line is quite narrow because
/// “question” was too large to fit? The greedy first-fit algorithm
/// doesn’t look ahead, so it has no other option than to put
/// “question” onto its own line.
///
/// With the optimal-fit wrapping algorithm, the previous lines are
/// shortened slightly in order to make the word “is” go into the
/// second last line:
///
/// ```
/// # #[cfg(feature = "smawk")] {
/// # use textwrap::{Options, WrapAlgorithm, wrap};
/// #
/// # let lines = wrap(
/// # "To be, or not to be: that is the question",
/// # Options::new(10).wrap_algorithm(WrapAlgorithm::new_optimal_fit())
/// # );
/// # assert_eq!(lines.join("\n") + "\n", "\
/// To be,
/// or not to
/// be: that
/// is the
/// question
/// # "); }
/// ```
///
/// Please see [`WrapAlgorithm`] for details on the choices.
///
/// # Examples
///
/// The returned iterator yields lines of type `Cow<'_, str>`. If
/// possible, the wrapped lines will borrow from the input string. As
/// an example, a hanging indentation, the first line can borrow from
/// the input, but the subsequent lines become owned strings:
///
/// ```
/// use std::borrow::Cow::{Borrowed, Owned};
/// use textwrap::{wrap, Options};
///
/// let options = Options::new(15).subsequent_indent("....");
/// let lines = wrap("Wrapping text all day long.", &options);
/// let annotated = lines
/// .iter()
/// .map(|line| match line {
/// Borrowed(text) => format!("[Borrowed] {}", text),
/// Owned(text) => format!("[Owned] {}", text),
/// })
/// .collect::>();
/// assert_eq!(
/// annotated,
/// &[
/// "[Borrowed] Wrapping text",
/// "[Owned] ....all day",
/// "[Owned] ....long.",
/// ]
/// );
/// ```
///
/// ## Leading and Trailing Whitespace
///
/// As a rule, leading whitespace (indentation) is preserved and
/// trailing whitespace is discarded.
///
/// In more details, when wrapping words into lines, words are found
/// by splitting the input text on space characters. One or more
/// spaces (shown here as “␣”) are attached to the end of each word:
///
/// ```text
/// "Foo␣␣␣bar␣baz" -> ["Foo␣␣␣", "bar␣", "baz"]
/// ```
///
/// These words are then put into lines. The interword whitespace is
/// preserved, unless the lines are wrapped so that the `"Foo␣␣␣"`
/// word falls at the end of a line:
///
/// ```
/// use textwrap::wrap;
///
/// assert_eq!(wrap("Foo bar baz", 10), vec!["Foo bar", "baz"]);
/// assert_eq!(wrap("Foo bar baz", 8), vec!["Foo", "bar baz"]);
/// ```
///
/// Notice how the trailing whitespace is removed in both case: in the
/// first example, `"bar␣"` becomes `"bar"` and in the second case
/// `"Foo␣␣␣"` becomes `"Foo"`.
///
/// Leading whitespace is preserved when the following word fits on
/// the first line. To understand this, consider how words are found
/// in a text with leading spaces:
///
/// ```text
/// "␣␣foo␣bar" -> ["␣␣", "foo␣", "bar"]
/// ```
///
/// When put into lines, the indentation is preserved if `"foo"` fits
/// on the first line, otherwise you end up with an empty line:
///
/// ```
/// use textwrap::wrap;
///
/// assert_eq!(wrap(" foo bar", 8), vec![" foo", "bar"]);
/// assert_eq!(wrap(" foo bar", 4), vec!["", "foo", "bar"]);
/// ```
pub fn wrap<'a, Opt>(text: &str, width_or_options: Opt) -> Vec>
where
Opt: Into>,
{
let options = width_or_options.into();
let initial_width = options
.width
.saturating_sub(core::display_width(options.initial_indent));
let subsequent_width = options
.width
.saturating_sub(core::display_width(options.subsequent_indent));
let mut lines = Vec::new();
for line in text.split('\n') {
let words = options.word_separator.find_words(line);
let split_words = word_splitters::split_words(words, &options.word_splitter);
let broken_words = if options.break_words {
let mut broken_words = core::break_words(split_words, subsequent_width);
if !options.initial_indent.is_empty() {
// Without this, the first word will always go into
// the first line. However, since we break words based
// on the _second_ line width, it can be wrong to
// unconditionally put the first word onto the first
// line. An empty zero-width word fixed this.
broken_words.insert(0, core::Word::from(""));
}
broken_words
} else {
split_words.collect::>()
};
let line_widths = [initial_width, subsequent_width];
let wrapped_words = options.wrap_algorithm.wrap(&broken_words, &line_widths);
let mut idx = 0;
for words in wrapped_words {
let last_word = match words.last() {
None => {
lines.push(Cow::from(""));
continue;
}
Some(word) => word,
};
// We assume here that all words are contiguous in `line`.
// That is, the sum of their lengths should add up to the
// length of `line`.
let len = words
.iter()
.map(|word| word.len() + word.whitespace.len())
.sum::()
- last_word.whitespace.len();
// The result is owned if we have indentation, otherwise
// we can simply borrow an empty string.
let mut result = if lines.is_empty() && !options.initial_indent.is_empty() {
Cow::Owned(options.initial_indent.to_owned())
} else if !lines.is_empty() && !options.subsequent_indent.is_empty() {
Cow::Owned(options.subsequent_indent.to_owned())
} else {
// We can use an empty string here since string
// concatenation for `Cow` preserves a borrowed value
// when either side is empty.
Cow::from("")
};
result += &line[idx..idx + len];
if !last_word.penalty.is_empty() {
result.to_mut().push_str(last_word.penalty);
}
lines.push(result);
// Advance by the length of `result`, plus the length of
// `last_word.whitespace` -- even if we had a penalty, we
// need to skip over the whitespace.
idx += len + last_word.whitespace.len();
}
}
lines
}
/// Wrap text into columns with a given total width.
///
/// The `left_gap`, `middle_gap` and `right_gap` arguments specify the
/// strings to insert before, between, and after the columns. The
/// total width of all columns and all gaps is specified using the
/// `total_width_or_options` argument. This argument can simply be an
/// integer if you want to use default settings when wrapping, or it
/// can be a [`Options`] value if you want to customize the wrapping.
///
/// If the columns are narrow, it is recommended to set
/// [`Options::break_words`] to `true` to prevent words from
/// protruding into the margins.
///
/// The per-column width is computed like this:
///
/// ```
/// # let (left_gap, middle_gap, right_gap) = ("", "", "");
/// # let columns = 2;
/// # let options = textwrap::Options::new(80);
/// let inner_width = options.width
/// - textwrap::core::display_width(left_gap)
/// - textwrap::core::display_width(right_gap)
/// - textwrap::core::display_width(middle_gap) * (columns - 1);
/// let column_width = inner_width / columns;
/// ```
///
/// The `text` is wrapped using [`wrap`] and the given `options`
/// argument, but the width is overwritten to the computed
/// `column_width`.
///
/// # Panics
///
/// Panics if `columns` is zero.
///
/// # Examples
///
/// ```
/// use textwrap::wrap_columns;
///
/// let text = "\
/// This is an example text, which is wrapped into three columns. \
/// Notice how the final column can be shorter than the others.";
///
/// #[cfg(feature = "smawk")]
/// assert_eq!(wrap_columns(text, 3, 50, "| ", " | ", " |"),
/// vec!["| This is | into three | column can be |",
/// "| an example | columns. | shorter than |",
/// "| text, which | Notice how | the others. |",
/// "| is wrapped | the final | |"]);
///
/// // Without the `smawk` feature, the middle column is a little more uneven:
/// #[cfg(not(feature = "smawk"))]
/// assert_eq!(wrap_columns(text, 3, 50, "| ", " | ", " |"),
/// vec!["| This is an | three | column can be |",
/// "| example text, | columns. | shorter than |",
/// "| which is | Notice how | the others. |",
/// "| wrapped into | the final | |"]);
pub fn wrap_columns<'a, Opt>(
text: &str,
columns: usize,
total_width_or_options: Opt,
left_gap: &str,
middle_gap: &str,
right_gap: &str,
) -> Vec
where
Opt: Into>,
{
assert!(columns > 0);
let mut options = total_width_or_options.into();
let inner_width = options
.width
.saturating_sub(core::display_width(left_gap))
.saturating_sub(core::display_width(right_gap))
.saturating_sub(core::display_width(middle_gap) * (columns - 1));
let column_width = std::cmp::max(inner_width / columns, 1);
options.width = column_width;
let last_column_padding = " ".repeat(inner_width % column_width);
let wrapped_lines = wrap(text, options);
let lines_per_column =
wrapped_lines.len() / columns + usize::from(wrapped_lines.len() % columns > 0);
let mut lines = Vec::new();
for line_no in 0..lines_per_column {
let mut line = String::from(left_gap);
for column_no in 0..columns {
match wrapped_lines.get(line_no + column_no * lines_per_column) {
Some(column_line) => {
line.push_str(column_line);
line.push_str(&" ".repeat(column_width - core::display_width(column_line)));
}
None => {
line.push_str(&" ".repeat(column_width));
}
}
if column_no == columns - 1 {
line.push_str(&last_column_padding);
} else {
line.push_str(middle_gap);
}
}
line.push_str(right_gap);
lines.push(line);
}
lines
}
/// Fill `text` in-place without reallocating the input string.
///
/// This function works by modifying the input string: some `' '`
/// characters will be replaced by `'\n'` characters. The rest of the
/// text remains untouched.
///
/// Since we can only replace existing whitespace in the input with
/// `'\n'`, we cannot do hyphenation nor can we split words longer
/// than the line width. We also need to use `AsciiSpace` as the word
/// separator since we need `' '` characters between words in order to
/// replace some of them with a `'\n'`. Indentation is also ruled out.
/// In other words, `fill_inplace(width)` behaves as if you had called
/// [`fill`] with these options:
///
/// ```
/// # use textwrap::{core, Options, WordSplitter, WordSeparator, WrapAlgorithm};
/// # let width = 80;
/// Options {
/// width: width,
/// initial_indent: "",
/// subsequent_indent: "",
/// break_words: false,
/// word_separator: WordSeparator::AsciiSpace,
/// wrap_algorithm: WrapAlgorithm::FirstFit,
/// word_splitter: WordSplitter::NoHyphenation,
/// };
/// ```
///
/// The wrap algorithm is [`WrapAlgorithm::FirstFit`] since this
/// is the fastest algorithm — and the main reason to use
/// `fill_inplace` is to get the string broken into newlines as fast
/// as possible.
///
/// A last difference is that (unlike [`fill`]) `fill_inplace` can
/// leave trailing whitespace on lines. This is because we wrap by
/// inserting a `'\n'` at the final whitespace in the input string:
///
/// ```
/// let mut text = String::from("Hello World!");
/// textwrap::fill_inplace(&mut text, 10);
/// assert_eq!(text, "Hello \nWorld!");
/// ```
///
/// If we didn't do this, the word `World!` would end up being
/// indented. You can avoid this if you make sure that your input text
/// has no double spaces.
///
/// # Performance
///
/// In benchmarks, `fill_inplace` is about twice as fast as [`fill`].
/// Please see the [`linear`
/// benchmark](https://github.com/mgeisler/textwrap/blob/master/benches/linear.rs)
/// for details.
pub fn fill_inplace(text: &mut String, width: usize) {
let mut indices = Vec::new();
let mut offset = 0;
for line in text.split('\n') {
let words = WordSeparator::AsciiSpace
.find_words(line)
.collect::>();
let wrapped_words = wrap_algorithms::wrap_first_fit(&words, &[width as f64]);
let mut line_offset = offset;
for words in &wrapped_words[..wrapped_words.len() - 1] {
let line_len = words
.iter()
.map(|word| word.len() + word.whitespace.len())
.sum::();
line_offset += line_len;
// We've advanced past all ' ' characters -- want to move
// one ' ' backwards and insert our '\n' there.
indices.push(line_offset - 1);
}
// Advance past entire line, plus the '\n' which was removed
// by the split call above.
offset += line.len() + 1;
}
let mut bytes = std::mem::take(text).into_bytes();
for idx in indices {
bytes[idx] = b'\n';
}
*text = String::from_utf8(bytes).unwrap();
}
#[cfg(test)]
mod tests {
use super::*;
#[cfg(feature = "hyphenation")]
use hyphenation::{Language, Load, Standard};
#[test]
fn options_agree_with_usize() {
let opt_usize = Options::from(42_usize);
let opt_options = Options::new(42);
assert_eq!(opt_usize.width, opt_options.width);
assert_eq!(opt_usize.initial_indent, opt_options.initial_indent);
assert_eq!(opt_usize.subsequent_indent, opt_options.subsequent_indent);
assert_eq!(opt_usize.break_words, opt_options.break_words);
assert_eq!(
opt_usize.word_splitter.split_points("hello-world"),
opt_options.word_splitter.split_points("hello-world")
);
}
#[test]
fn no_wrap() {
assert_eq!(wrap("foo", 10), vec!["foo"]);
}
#[test]
fn wrap_simple() {
assert_eq!(wrap("foo bar baz", 5), vec!["foo", "bar", "baz"]);
}
#[test]
fn to_be_or_not() {
assert_eq!(
wrap(
"To be, or not to be, that is the question.",
Options::new(10).wrap_algorithm(WrapAlgorithm::FirstFit)
),
vec!["To be, or", "not to be,", "that is", "the", "question."]
);
}
#[test]
fn multiple_words_on_first_line() {
assert_eq!(wrap("foo bar baz", 10), vec!["foo bar", "baz"]);
}
#[test]
fn long_word() {
assert_eq!(wrap("foo", 0), vec!["f", "o", "o"]);
}
#[test]
fn long_words() {
assert_eq!(wrap("foo bar", 0), vec!["f", "o", "o", "b", "a", "r"]);
}
#[test]
fn max_width() {
assert_eq!(wrap("foo bar", usize::MAX), vec!["foo bar"]);
let text = "Hello there! This is some English text. \
It should not be wrapped given the extents below.";
assert_eq!(wrap(text, usize::MAX), vec![text]);
}
#[test]
fn leading_whitespace() {
assert_eq!(wrap(" foo bar", 6), vec![" foo", "bar"]);
}
#[test]
fn leading_whitespace_empty_first_line() {
// If there is no space for the first word, the first line
// will be empty. This is because the string is split into
// words like [" ", "foobar ", "baz"], which puts "foobar " on
// the second line. We never output trailing whitespace
assert_eq!(wrap(" foobar baz", 6), vec!["", "foobar", "baz"]);
}
#[test]
fn trailing_whitespace() {
// Whitespace is only significant inside a line. After a line
// gets too long and is broken, the first word starts in
// column zero and is not indented.
assert_eq!(wrap("foo bar baz ", 5), vec!["foo", "bar", "baz"]);
}
#[test]
fn issue_99() {
// We did not reset the in_whitespace flag correctly and did
// not handle single-character words after a line break.
assert_eq!(
wrap("aaabbbccc x yyyzzzwww", 9),
vec!["aaabbbccc", "x", "yyyzzzwww"]
);
}
#[test]
fn issue_129() {
// The dash is an em-dash which takes up four bytes. We used
// to panic since we tried to index into the character.
let options = Options::new(1).word_separator(WordSeparator::AsciiSpace);
assert_eq!(wrap("x – x", options), vec!["x", "–", "x"]);
}
#[test]
fn wide_character_handling() {
assert_eq!(wrap("Hello, World!", 15), vec!["Hello, World!"]);
assert_eq!(
wrap(
"Ｈｅｌｌｏ, Ｗｏｒｌｄ!",
Options::new(15).word_separator(WordSeparator::AsciiSpace)
),
vec!["Ｈｅｌｌｏ,", "Ｗｏｒｌｄ!"]
);
// Wide characters are allowed to break if the
// unicode-linebreak feature is enabled.
#[cfg(feature = "unicode-linebreak")]
assert_eq!(
wrap(
"Ｈｅｌｌｏ, Ｗｏｒｌｄ!",
Options::new(15).word_separator(WordSeparator::UnicodeBreakProperties)
),
vec!["Ｈｅｌｌｏ, Ｗ", "ｏｒｌｄ!"]
);
}
#[test]
fn empty_line_is_indented() {
// Previously, indentation was not applied to empty lines.
// However, this is somewhat inconsistent and undesirable if
// the indentation is something like a border ("| ") which you
// want to apply to all lines, empty or not.
let options = Options::new(10).initial_indent("!!!");
assert_eq!(fill("", &options), "!!!");
}
#[test]
fn indent_single_line() {
let options = Options::new(10).initial_indent(">>>"); // No trailing space
assert_eq!(fill("foo", &options), ">>>foo");
}
#[test]
fn indent_first_emoji() {
let options = Options::new(10).initial_indent("👉👉");
assert_eq!(
wrap("x x x x x x x x x x x x x", &options),
vec!["👉👉x x x", "x x x x x", "x x x x x"]
);
}
#[test]
fn indent_multiple_lines() {
let options = Options::new(6).initial_indent("* ").subsequent_indent(" ");
assert_eq!(
wrap("foo bar baz", &options),
vec!["* foo", " bar", " baz"]
);
}
#[test]
fn indent_break_words() {
let options = Options::new(5).initial_indent("* ").subsequent_indent(" ");
assert_eq!(wrap("foobarbaz", &options), vec!["* foo", " bar", " baz"]);
}
#[test]
fn initial_indent_break_words() {
// This is a corner-case showing how the long word is broken
// according to the width of the subsequent lines. The first
// fragment of the word no longer fits on the first line,
// which ends up being pure indentation.
let options = Options::new(5).initial_indent("-->");
assert_eq!(wrap("foobarbaz", &options), vec!["-->", "fooba", "rbaz"]);
}
#[test]
fn hyphens() {
assert_eq!(wrap("foo-bar", 5), vec!["foo-", "bar"]);
}
#[test]
fn trailing_hyphen() {
let options = Options::new(5).break_words(false);
assert_eq!(wrap("foobar-", &options), vec!["foobar-"]);
}
#[test]
fn multiple_hyphens() {
assert_eq!(wrap("foo-bar-baz", 5), vec!["foo-", "bar-", "baz"]);
}
#[test]
fn hyphens_flag() {
let options = Options::new(5).break_words(false);
assert_eq!(
wrap("The --foo-bar flag.", &options),
vec!["The", "--foo-", "bar", "flag."]
);
}
#[test]
fn repeated_hyphens() {
let options = Options::new(4).break_words(false);
assert_eq!(wrap("foo--bar", &options), vec!["foo--bar"]);
}
#[test]
fn hyphens_alphanumeric() {
assert_eq!(wrap("Na2-CH4", 5), vec!["Na2-", "CH4"]);
}
#[test]
fn hyphens_non_alphanumeric() {
let options = Options::new(5).break_words(false);
assert_eq!(wrap("foo(-)bar", &options), vec!["foo(-)bar"]);
}
#[test]
fn multiple_splits() {
assert_eq!(wrap("foo-bar-baz", 9), vec!["foo-bar-", "baz"]);
}
#[test]
fn forced_split() {
let options = Options::new(5).break_words(false);
assert_eq!(wrap("foobar-baz", &options), vec!["foobar-", "baz"]);
}
#[test]
fn multiple_unbroken_words_issue_193() {
let options = Options::new(3).break_words(false);
assert_eq!(
wrap("small large tiny", &options),
vec!["small", "large", "tiny"]
);
assert_eq!(
wrap("small large tiny", &options),
vec!["small", "large", "tiny"]
);
}
#[test]
fn very_narrow_lines_issue_193() {
let options = Options::new(1).break_words(false);
assert_eq!(wrap("fooo x y", &options), vec!["fooo", "x", "y"]);
assert_eq!(wrap("fooo x y", &options), vec!["fooo", "x", "y"]);
}
#[test]
fn simple_hyphens() {
let options = Options::new(8).word_splitter(WordSplitter::HyphenSplitter);
assert_eq!(wrap("foo bar-baz", &options), vec!["foo bar-", "baz"]);
}
#[test]
fn no_hyphenation() {
let options = Options::new(8).word_splitter(WordSplitter::NoHyphenation);
assert_eq!(wrap("foo bar-baz", &options), vec!["foo", "bar-baz"]);
}
#[test]
#[cfg(feature = "hyphenation")]
fn auto_hyphenation_double_hyphenation() {
let dictionary = Standard::from_embedded(Language::EnglishUS).unwrap();
let options = Options::new(10);
assert_eq!(
wrap("Internationalization", &options),
vec!["Internatio", "nalization"]
);
let options = Options::new(10).word_splitter(WordSplitter::Hyphenation(dictionary));
assert_eq!(
wrap("Internationalization", &options),
vec!["Interna-", "tionaliza-", "tion"]
);
}
#[test]
#[cfg(feature = "hyphenation")]
fn auto_hyphenation_issue_158() {
let dictionary = Standard::from_embedded(Language::EnglishUS).unwrap();
let options = Options::new(10);
assert_eq!(
wrap("participation is the key to success", &options),
vec!["participat", "ion is", "the key to", "success"]
);
let options = Options::new(10).word_splitter(WordSplitter::Hyphenation(dictionary));
assert_eq!(
wrap("participation is the key to success", &options),
vec!["partici-", "pation is", "the key to", "success"]
);
}
#[test]
#[cfg(feature = "hyphenation")]
fn split_len_hyphenation() {
// Test that hyphenation takes the width of the whitespace
// into account.
let dictionary = Standard::from_embedded(Language::EnglishUS).unwrap();
let options = Options::new(15).word_splitter(WordSplitter::Hyphenation(dictionary));
assert_eq!(
wrap("garbage collection", &options),
vec!["garbage col-", "lection"]
);
}
#[test]
#[cfg(feature = "hyphenation")]
fn borrowed_lines() {
// Lines that end with an extra hyphen are owned, the final
// line is borrowed.
use std::borrow::Cow::{Borrowed, Owned};
let dictionary = Standard::from_embedded(Language::EnglishUS).unwrap();
let options = Options::new(10).word_splitter(WordSplitter::Hyphenation(dictionary));
let lines = wrap("Internationalization", &options);
assert_eq!(lines, vec!["Interna-", "tionaliza-", "tion"]);
if let Borrowed(s) = lines[0] {
assert!(false, "should not have been borrowed: {:?}", s);
}
if let Borrowed(s) = lines[1] {
assert!(false, "should not have been borrowed: {:?}", s);
}
if let Owned(ref s) = lines[2] {
assert!(false, "should not have been owned: {:?}", s);
}
}
#[test]
#[cfg(feature = "hyphenation")]
fn auto_hyphenation_with_hyphen() {
let dictionary = Standard::from_embedded(Language::EnglishUS).unwrap();
let options = Options::new(8).break_words(false);
assert_eq!(
wrap("over-caffinated", &options),
vec!["over-", "caffinated"]
);
let options = options.word_splitter(WordSplitter::Hyphenation(dictionary));
assert_eq!(
wrap("over-caffinated", &options),
vec!["over-", "caffi-", "nated"]
);
}
#[test]
fn break_words() {
assert_eq!(wrap("foobarbaz", 3), vec!["foo", "bar", "baz"]);
}
#[test]
fn break_words_wide_characters() {
// Even the poor man's version of `ch_width` counts these
// characters as wide.
let options = Options::new(5).word_separator(WordSeparator::AsciiSpace);
assert_eq!(wrap("Ｈｅｌｌｏ", options), vec!["Ｈｅ", "ｌｌ", "ｏ"]);
}
#[test]
fn break_words_zero_width() {
assert_eq!(wrap("foobar", 0), vec!["f", "o", "o", "b", "a", "r"]);
}
#[test]
fn break_long_first_word() {
assert_eq!(wrap("testx y", 4), vec!["test", "x y"]);
}
#[test]
fn break_words_line_breaks() {
assert_eq!(fill("ab\ncdefghijkl", 5), "ab\ncdefg\nhijkl");
assert_eq!(fill("abcdefgh\nijkl", 5), "abcde\nfgh\nijkl");
}
#[test]
fn break_words_empty_lines() {
assert_eq!(
fill("foo\nbar", &Options::new(2).break_words(false)),
"foo\nbar"
);
}
#[test]
fn preserve_line_breaks() {
assert_eq!(fill("", 80), "");
assert_eq!(fill("\n", 80), "\n");
assert_eq!(fill("\n\n\n", 80), "\n\n\n");
assert_eq!(fill("test\n", 80), "test\n");
assert_eq!(fill("test\n\na\n\n", 80), "test\n\na\n\n");
assert_eq!(
fill(
"1 3 5 7\n1 3 5 7",
Options::new(7).wrap_algorithm(WrapAlgorithm::FirstFit)
),
"1 3 5 7\n1 3 5 7"
);
assert_eq!(
fill(
"1 3 5 7\n1 3 5 7",
Options::new(5).wrap_algorithm(WrapAlgorithm::FirstFit)
),
"1 3 5\n7\n1 3 5\n7"
);
}
#[test]
fn preserve_line_breaks_with_whitespace() {
assert_eq!(fill(" ", 80), "");
assert_eq!(fill(" \n ", 80), "\n");
assert_eq!(fill(" \n \n \n ", 80), "\n\n\n");
}
#[test]
fn non_breaking_space() {
let options = Options::new(5).break_words(false);
assert_eq!(fill("foo bar baz", &options), "foo bar baz");
}
#[test]
fn non_breaking_hyphen() {
let options = Options::new(5).break_words(false);
assert_eq!(fill("foo‑bar‑baz", &options), "foo‑bar‑baz");
}
#[test]
fn fill_simple() {
assert_eq!(fill("foo bar baz", 10), "foo bar\nbaz");
}
#[test]
fn fill_colored_text() {
// The words are much longer than 6 bytes, but they remain
// intact after filling the text.
let green_hello = "\u{1b}[0m\u{1b}[32mHello\u{1b}[0m";
let blue_world = "\u{1b}[0m\u{1b}[34mWorld!\u{1b}[0m";
assert_eq!(
fill(&(String::from(green_hello) + " " + &blue_world), 6),
String::from(green_hello) + "\n" + &blue_world
);
}
#[test]
fn fill_unicode_boundary() {
// https://github.com/mgeisler/textwrap/issues/390
fill("\u{1b}!Ͽ", 10);
}
#[test]
fn fill_inplace_empty() {
let mut text = String::from("");
fill_inplace(&mut text, 80);
assert_eq!(text, "");
}
#[test]
fn fill_inplace_simple() {
let mut text = String::from("foo bar baz");
fill_inplace(&mut text, 10);
assert_eq!(text, "foo bar\nbaz");
}
#[test]
fn fill_inplace_multiple_lines() {
let mut text = String::from("Some text to wrap over multiple lines");
fill_inplace(&mut text, 12);
assert_eq!(text, "Some text to\nwrap over\nmultiple\nlines");
}
#[test]
fn fill_inplace_long_word() {
let mut text = String::from("Internationalization is hard");
fill_inplace(&mut text, 10);
assert_eq!(text, "Internationalization\nis hard");
}
#[test]
fn fill_inplace_no_hyphen_splitting() {
let mut text = String::from("A well-chosen example");
fill_inplace(&mut text, 10);
assert_eq!(text, "A\nwell-chosen\nexample");
}
#[test]
fn fill_inplace_newlines() {
let mut text = String::from("foo bar\n\nbaz\n\n\n");
fill_inplace(&mut text, 10);
assert_eq!(text, "foo bar\n\nbaz\n\n\n");
}
#[test]
fn fill_inplace_newlines_reset_line_width() {
let mut text = String::from("1 3 5\n1 3 5 7 9\n1 3 5 7 9 1 3");
fill_inplace(&mut text, 10);
assert_eq!(text, "1 3 5\n1 3 5 7 9\n1 3 5 7 9\n1 3");
}
#[test]
fn fill_inplace_leading_whitespace() {
let mut text = String::from(" foo bar baz");
fill_inplace(&mut text, 10);
assert_eq!(text, " foo bar\nbaz");
}
#[test]
fn fill_inplace_trailing_whitespace() {
let mut text = String::from("foo bar baz ");
fill_inplace(&mut text, 10);
assert_eq!(text, "foo bar\nbaz ");
}
#[test]
fn fill_inplace_interior_whitespace() {
// To avoid an unwanted indentation of "baz", it is important
// to replace the final ' ' with '\n'.
let mut text = String::from("foo bar baz");
fill_inplace(&mut text, 10);
assert_eq!(text, "foo bar \nbaz");
}
#[test]
fn unfill_simple() {
let (text, options) = unfill("foo\nbar");
assert_eq!(text, "foo bar");
assert_eq!(options.width, 3);
}
#[test]
fn unfill_trailing_newlines() {
let (text, options) = unfill("foo\nbar\n\n\n");
assert_eq!(text, "foo bar\n\n\n");
assert_eq!(options.width, 3);
}
#[test]
fn unfill_initial_indent() {
let (text, options) = unfill(" foo\nbar\nbaz");
assert_eq!(text, "foo bar baz");
assert_eq!(options.width, 5);
assert_eq!(options.initial_indent, " ");
}
#[test]
fn unfill_differing_indents() {
let (text, options) = unfill(" foo\n bar\n baz");
assert_eq!(text, "foo bar baz");
assert_eq!(options.width, 7);
assert_eq!(options.initial_indent, " ");
assert_eq!(options.subsequent_indent, " ");
}
#[test]
fn unfill_list_item() {
let (text, options) = unfill("* foo\n bar\n baz");
assert_eq!(text, "foo bar baz");
assert_eq!(options.width, 5);
assert_eq!(options.initial_indent, "* ");
assert_eq!(options.subsequent_indent, " ");
}
#[test]
fn unfill_multiple_char_prefix() {
let (text, options) = unfill(" // foo bar\n // baz\n // quux");
assert_eq!(text, "foo bar baz quux");
assert_eq!(options.width, 14);
assert_eq!(options.initial_indent, " // ");
assert_eq!(options.subsequent_indent, " // ");
}
#[test]
fn unfill_block_quote() {
let (text, options) = unfill("> foo\n> bar\n> baz");
assert_eq!(text, "foo bar baz");
assert_eq!(options.width, 5);
assert_eq!(options.initial_indent, "> ");
assert_eq!(options.subsequent_indent, "> ");
}
#[test]
fn unfill_whitespace() {
assert_eq!(unfill("foo bar").0, "foo bar");
}
#[test]
fn wrap_columns_empty_text() {
assert_eq!(wrap_columns("", 1, 10, "| ", "", " |"), vec!["| |"]);
}
#[test]
fn wrap_columns_single_column() {
assert_eq!(
wrap_columns("Foo", 3, 30, "| ", " | ", " |"),
vec!["| Foo | | |"]
);
}
#[test]
fn wrap_columns_uneven_columns() {
// The gaps take up a total of 5 columns, so the columns are
// (21 - 5)/4 = 4 columns wide:
assert_eq!(
wrap_columns("Foo Bar Baz Quux", 4, 21, "|", "|", "|"),
vec!["|Foo |Bar |Baz |Quux|"]
);
// As the total width increases, the last column absorbs the
// excess width:
assert_eq!(
wrap_columns("Foo Bar Baz Quux", 4, 24, "|", "|", "|"),
vec!["|Foo |Bar |Baz |Quux |"]
);
// Finally, when the width is 25, the columns can be resized
// to a width of (25 - 5)/4 = 5 columns:
assert_eq!(
wrap_columns("Foo Bar Baz Quux", 4, 25, "|", "|", "|"),
vec!["|Foo |Bar |Baz |Quux |"]
);
}
#[test]
#[cfg(feature = "unicode-width")]
fn wrap_columns_with_emojis() {
assert_eq!(
wrap_columns(
"Words and a few emojis 😍 wrapped in ⓶ columns",
2,
30,
"✨ ",
" ⚽ ",
" 👀"
),
vec![
"✨ Words ⚽ wrapped in 👀",
"✨ and a few ⚽ ⓶ columns 👀",
"✨ emojis 😍 ⚽ 👀"
]
);
}
#[test]
fn wrap_columns_big_gaps() {
// The column width shrinks to 1 because the gaps take up all
// the space.
assert_eq!(
wrap_columns("xyz", 2, 10, "----> ", " !!! ", " <----"),
vec![
"----> x !!! z <----", //
"----> y !!! <----"
]
);
}
#[test]
#[should_panic]
fn wrap_columns_panic_with_zero_columns() {
wrap_columns("", 0, 10, "", "", "");
}
}