README
¶
linewrap
Wraps either a string or a byte slice so that each line doesn't exceed the specified number of characters. A character is defined as a unicode code point, not a byte. Any \r in the input will be elided.
Trailing and leading spaces on wrapped lines are elided.
Linewrap can also indent wrapped lines or format the input as comments:
# line comment
// line comment
/* */ block comment
References used:
Jukka "Yucca" Korpela's unicode tables were used as the main references especially his line break page: https://www.cs.tut.fi/~jkorpela/unicode/linebr.html and his unicode spaces and dash pages listed in their respective sections in this document.
In addition, some of the symbols were pulled from http://www.unicode.org/reports/tr14/#Properties.
The list of symbols handled is not exhaustive.
Hyphen and spaces
Linewrap will wrap lines on most unicode whitespace and dash characters, with some exceptions. Characters in the not considered list will not be considered points at which the input can be wrapped. If there are any characters that are unaccounted for, please file an issue or make a pull request. Before doing so, check the docs and/or the code to see if it has been already listed as an exception.
The \n and \t characters are handled separately. The width used for tabs is set by Wrap.TabSize(int), which defaults to 8 spaces.
Spaces
Whitespace tokens are mostly from https://www.cs.tut.fi/~jkorpela/chars/spaces.html
Not considered whitespace characters:
| code point | symbol name |
|---|---|
| U+00A0 | no-break space |
| U+202F | zero width no-break space |
Whitespace characters
code point|symbol name
--|:--|:--
U+0020|space
U+1680|ogham space mark
U+180E|mongolian vowel separator
U+2000|en quad
U+2001|em quad
U+2002|en space
U+2003|em space
U+2004|three per em space
U+2005|four per em space
U+2006|six per em space
U+2007|figure space
U+2008|punctuation space
U+2009|thin space
U+200A|hair space
U+200B|zero width space
U+205F|medium mathematical space
U+3000|ideographic space
Dashes (Hyphens)
Dash tokens are mostly from dash tokens from https://www.cs.tut.fi/~jkorpela/dashes.html
Additional explanations to entries in the tables:
The em dash (U+2014) symbol can have a break before or after its occurrence but linewrap only breaks after its occurrence.
The hyphen minus (U+002D) is not supposed to break on a numeric context but linewrap does not make such a differentiation.
Dash characters not considered dashes
| code point | symbol name |
|---|---|
| U+007E | tilde |
| U+2212 | minus sign |
| U+301C | wavy dash |
| U+3939 | wavy dash |
| U+1806 | mongolian todo hyphen |
Dash characters
| code point | symbol name |
|---|---|
| U+002D | hyphen minus |
| U+00AD | soft hyphen |
| U+058A | armenian hyphen |
| U+2010 | hyphen |
| U+2012 | figure dash |
| U+2013 | en dash |
| U+2014 | em dash |
| U+2015 | horizontal bar |
| U+2053 | swung dash |
| U+207B | superscript mnus |
| U+208B | subscript minus |
| U+2E3A | two em dash |
| U+2E3B | three em dash |
| U+FE31 | presentation form for vertical em dash |
| U+FE32 | presentation form for vertical en dash |
| U+FE58 | small em dash |
| U+FE63 | small hyphen minus |
| U+FF0D | full width hyphen minus |
Documentation
¶
Overview ¶
Package linewrap wraps text so that they are n characters, or less in length. Wrapped lines can be indented or turned into comments; c, c++, and shell style comments are supported.
Any /r characters encountered will be elided during the wrapping process; only /n is supported for new lines.
The size of tabs is configurable.
With a few exceptions, lines can be wrapped at unicode dash and whitespace characters.
The classification of unicode tokens is drawn from Jukka "Yucca" Korpela's unicode tables on: https://www.cs.tut.fi/~jkorpela/unicode/linebr.html, https://www.cs.tut.fi/~jkorpela/chars/spaces.html, and https://www.cs.tut.fi/~jkorpela/dashes.html. Additionally, information from http://www.unicode.org/reports/tr14/#Properties was used.
The list of symbols handled is not exhaustive.
Line breaks may be inserted before or after whitespace characters. Any trailing spaces on a line will be elided. With the exception of indentation, all leading whitespaces on a wrapped line will be elided.
space U+0020 ogham space mark U+1680 mongolian vowel separator U+180E en quad U+2000 em quad U+2001 en space U+2002 em space U+2003 three per em space U+2004 four per em space U+2005 six per em space U+2006 figure space U+2007 punctuation space U+2008 thin space U+2009 hair space U+200A zero width space U+200B medium mathematical space U+205F ideographic space U+3000
Exceptions to whitespace characters (no break will occur):
no-break space U+00A0 zero width no-break space U+202F
Line breaks may be inserted after a dash (hyphen) character. An em dash (U+2014) can have a break before or after its occurrence but linewrap will only break after its occurrence. A hyphen minus (U+002D) is not supposed to break on a numeric context but linewrap does not make that differentiation.
hyphen minus U+002D soft hyphen U+00AD armenian hyphen U+058A hyphen U+2010 figure dash U+2012 en dash U+2013 em dash U+2014 horizontal bar U+2015 swung dash U+2053 superscript mnus U+207B subscript minus U+208B two em dash U+2E3A three em dash U+2E3B presentation form for vertical em dash U+FE31 presentation form for vertical en dash U+FE32 small em dash U+FE58 small hyphen minus U+FE63 full width hyphen minus U+FF0D
Exceptions to dash characters (no break will occur):
tilde U+007E minus sign U+2212 wavy dash U+301C wavy dash U+3939 mongolian todo hyphen U+1806
Index ¶
Constants ¶
const ( LineLength = 80 // default line length TabSize = 8 // default tab size )
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type CommentStyle ¶
type CommentStyle int
const ( NoComment CommentStyle = iota CPPComment // C++ style line comment: // ShellComment // shell style line comment: # CComment // c style block comment: /* */ )
func ParseCommentStyle ¶
func ParseCommentStyle(s string) CommentStyle
func (CommentStyle) String ¶
func (c CommentStyle) String() string
type Wrapper ¶
type Wrapper struct {
Length int // Max length of the line.
CommentStyle // the type of comment,
// contains filtered or unexported fields
}
Wrapper wraps lines so that the output is lines of Length characters or less.
func (*Wrapper) IndentText ¶
IndentText sets the value that should be used to indent wrapped lines.
func (*Wrapper) Reset ¶
func (w *Wrapper) Reset()
Reset resets the non-configuration fields so that it's usable for a new input. The Wrapper's configuration is not affected.
Source Files