Enum textwrap::WordSeparator

pub enum WordSeparator {
    AsciiSpace,
    UnicodeBreakProperties,
    Custom(fn(line: &str) -> Box<dyn Iterator<Item = Word<'_>> + '_>),
}

Describes where words occur in a line of text.

The simplest approach is say that words are separated by one or more ASCII spaces (' '). This works for Western languages without emojis. A more complex approach is to use the Unicode line breaking algorithm, which finds break points in non-ASCII text.

The line breaks occur between words, please see WordSplitter for options of how to handle hyphenation of individual words.

Examples

use textwrap::core::Word;
use textwrap::WordSeparator::AsciiSpace;

let words = AsciiSpace.find_words("Hello World!").collect::<Vec<_>>();
assert_eq!(words, vec![Word::from("Hello "), Word::from("World!")]);

Variants

AsciiSpace

Find words by splitting on runs of ' ' characters.

Examples

use textwrap::core::Word;
use textwrap::WordSeparator::AsciiSpace;

let words = AsciiSpace.find_words("Hello   World!").collect::<Vec<_>>();
assert_eq!(words, vec![Word::from("Hello   "),
                       Word::from("World!")]);

UnicodeBreakProperties

Split line into words using Unicode break properties.

This word separator uses the Unicode line breaking algorithm described in Unicode Standard Annex #14 to find legal places to break lines. There is a small difference in that the U+002D (Hyphen-Minus) and U+00AD (Soft Hyphen) don’t create a line break: to allow a line break at a hyphen, use WordSplitter::HyphenSplitter. Soft hyphens are not currently supported.

Examples

Unlike WordSeparator::AsciiSpace, the Unicode line breaking algorithm will find line break opportunities between some characters with no intervening whitespace:

#[cfg(feature = "unicode-linebreak")] {
use textwrap::core::Word;
use textwrap::WordSeparator::UnicodeBreakProperties;

assert_eq!(UnicodeBreakProperties.find_words("Emojis: 😂😍").collect::<Vec<_>>(),
           vec![Word::from("Emojis: "),
                Word::from("😂"),
                Word::from("😍")]);

assert_eq!(UnicodeBreakProperties.find_words("CJK: 你好").collect::<Vec<_>>(),
           vec![Word::from("CJK: "),
                Word::from("你"),
                Word::from("好")]);
}

A U+2060 (Word Joiner) character can be inserted if you want to manually override the defaults and keep the characters together:

#[cfg(feature = "unicode-linebreak")] {
use textwrap::core::Word;
use textwrap::WordSeparator::UnicodeBreakProperties;

assert_eq!(UnicodeBreakProperties.find_words("Emojis: 😂\u{2060}😍").collect::<Vec<_>>(),
           vec![Word::from("Emojis: "),
                Word::from("😂\u{2060}😍")]);
}

The Unicode line breaking algorithm will also automatically suppress break breaks around certain punctuation characters::

#[cfg(feature = "unicode-linebreak")] {
use textwrap::core::Word;
use textwrap::WordSeparator::UnicodeBreakProperties;

assert_eq!(UnicodeBreakProperties.find_words("[ foo ] bar !").collect::<Vec<_>>(),
           vec![Word::from("[ foo ] "),
                Word::from("bar !")]);
}

Custom(fn(line: &str) -> Box<dyn Iterator<Item = Word<'_>> + '_>)

Find words using a custom word separator

Implementations

impl WordSeparator

pub const fn new() -> Self

Create a new word separator.

The best available algorithm is used by default, i.e., WordSeparator::UnicodeBreakProperties if available, otherwise WordSeparator::AsciiSpace.

pub fn find_words<'a>( &self, line: &'a str ) -> Box<dyn Iterator<Item = Word<'a>> + 'a>

Find all words in line.

Trait Implementations

impl Clone for WordSeparator

fn clone(&self) -> WordSeparator

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for WordSeparator

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for WordSeparator

fn eq(&self, other: &Self) -> bool

Compare two word separators.

use textwrap::WordSeparator;

assert_eq!(WordSeparator::AsciiSpace, WordSeparator::AsciiSpace);
#[cfg(feature = "unicode-linebreak")] {
    assert_eq!(WordSeparator::UnicodeBreakProperties,
               WordSeparator::UnicodeBreakProperties);
}

Note that WordSeparator::Custom values never compare equal:

use textwrap::WordSeparator;
use textwrap::core::Word;
fn word_separator(line: &str) -> Box<dyn Iterator<Item = Word<'_>> + '_> {
    Box::new(line.split_inclusive(' ').map(Word::from))
}
assert_ne!(WordSeparator::Custom(word_separator),
           WordSeparator::Custom(word_separator));

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for WordSeparator