// Partial port of python's argparse module, version 3.9.0 (only wrap and fill functions):
// https://github.com/python/cpython/blob/v3.9.0b4/Lib/textwrap.py
'use strict'
/*
* Text wrapping and filling.
*/
// Copyright (C) 1999-2001 Gregory P. Ward.
// Copyright (C) 2002, 2003 Python Software Foundation.
// Copyright (C) 2020 argparse.js authors
// Originally written by Greg Ward <gward@python.net>
// Hardcode the recognized whitespace characters to the US-ASCII
// whitespace characters. The main reason for doing this is that
// some Unicode spaces (like \u00a0) are non-breaking whitespaces.
//
// This less funky little regex just split on recognized spaces. E.g.
// "Hello there -- you goof-ball, use the -b option!"
// splits into
// Hello/ /there/ /--/ /you/ /goof-ball,/ /use/ /the/ /-b/ /option!/
const wordsep_simple_re = /([\t\n\x0b\x0c\r ]+)/
class TextWrapper {
/*
* Object for wrapping/filling text. The public interface consists of
* the wrap() and fill() methods; the other methods are just there for
* subclasses to override in order to tweak the default behaviour.
* If you want to completely replace the main wrapping algorithm,
* you'll probably have to override _wrap_chunks().
*
* Several instance attributes control various aspects of wrapping:
* width (default: 70)
* the maximum width of wrapped lines (unless break_long_words
* is false)
* initial_indent (default: "")
* string that will be prepended to the first line of wrapped
* output. Counts towards the line's width.
* subsequent_indent (default: "")
* string that will be prepended to all lines save the first
* of wrapped output; also counts towards each line's width.
* expand_tabs (default: true)
* Expand tabs in input text to spaces before further processing.
* Each tab will become 0 .. 'tabsize' spaces, depending on its position
* in its line. If false, each tab is treated as a single character.
* tabsize (default: 8)
* Expand tabs in input text to 0 .. 'tabsize' spaces, unless
* 'expand_tabs' is false.
* replace_whitespace (default: true)
* Replace all whitespace characters in the input text by spaces
* after tab expansion. Note that if expand_tabs is false and
* replace_whitespace is true, every tab will be converted to a
* single space!
* fix_sentence_endings (default: false)
* Ensure that sentence-ending punctuation is always followed
* by two spaces. Off by default because the algorithm is
* (unavoidably) imperfect.
* break_long_words (default: true)
* Break words longer than 'width'. If false, those words will not
* be broken, and some lines might be longer than 'width'.
* break_on_hyphens (default: true)
* Allow breaking hyphenated words. If true, wrapping will occur
* preferably on whitespaces and right after hyphens part of
* compound words.
* drop_whitespace (default: true)
* Drop leading and trailing whitespace from lines.
* max_lines (default: None)
* Truncate wrapped lines.
* placeholder (default: ' [...]')
* Append to the last line of truncated text.
*/
constructor(options = {}) {
let {
width = 70,
initial_indent = '',
subsequent_indent = '',
expand_tabs = true,
replace_whitespace = true,
fix_sentence_endings = false,
break_long_words = true,
drop_whitespace = true,
break_on_hyphens = true,
tabsize = 8,
max_lines = undefined,
placeholder=' [...]'
} = options
this.width = width
this.initial_indent = initial_indent
this.subsequent_indent = subsequent_indent
this.expand_tabs = expand_tabs
this.replace_whitespace = replace_whitespace
this.fix_sentence_endings = fix_sentence_endings
this.break_long_words = break_long_words
this.drop_whitespace = drop_whitespace
this.break_on_hyphens = break_on_hyphens
this.tabsize = tabsize
this.max_lines = max_lines
this.placeholder = placeholder
}
// -- Private methods -----------------------------------------------
// (possibly useful for subclasses to override)
_munge_whitespace(text) {
/*
* _munge_whitespace(text : string) -> string
*
* Munge whitespace in text: expand tabs and convert all other
* whitespace characters to spaces. Eg. " foo\\tbar\\n\\nbaz"
* becomes " foo bar baz".
*/
if (this.expand_tabs) {
text = text.replace(/\t/g, ' '.repeat(this.tabsize)) // not strictly correct in js
}
if (this.replace_whitespace) {
text = text.replace(/[\t\n\x0b\x0c\r]/g, ' ')
}
return text
}
_split(text) {
/*
* _split(text : string) -> [string]
*
* Split the text to wrap into indivisible chunks. Chunks are
* not quite the same as words; see _wrap_chunks() for full
* details. As an example, the text
* Look, goof-ball -- use the -b option!
* breaks into the following chunks:
* 'Look,', ' ', 'goof-', 'ball', ' ', '--', ' ',
* 'use', ' ', 'the', ' ', '-b', ' ', 'option!'
* if break_on_hyphens is True, or in:
* 'Look,', ' ', 'goof-ball', ' ', '--', ' ',
* 'use', ' ', 'the', ' ', '-b', ' ', option!'
* otherwise.
*/
let chunks = text.split(wordsep_simple_re)
chunks = chunks.filter(Boolean)
return chunks
}
_handle_long_word(reversed_chunks, cur_line, cur_len, width) {
/*
* _handle_long_word(chunks : [string],
* cur_line : [string],
* cur_len : int, width : int)
*
* Handle a chunk of text (most likely a word, not whitespace) that
* is too long to fit in any line.
*/
// Figure out when indent is larger than the specified width, and make
// sure at least one character is stripped off on every pass
let space_left
if (width < 1) {
space_left = 1
} else {
space_left = width - cur_len
}
// If we're allowed to break long words, then do so: put as much
// of the next chunk onto the current line as will fit.
if (this.break_long_words) {
cur_line.push(reversed_chunks[reversed_chunks.length - 1].slice(0, space_left))
reversed_chunks[reversed_chunks.length - 1] = reversed_chunks[reversed_chunks.length - 1].slice(space_left)
// Otherwise, we have to preserve the long word intact. Only add
// it to the current line if there's nothing already there --
// that minimizes how much we violate the width constraint.
} else if (!cur_line) {
cur_line.push(...reversed_chunks.pop())
}
// If we're not allowed to break long words, and there's already
// text on the current line, do nothing. Next time through the
// main loop of _wrap_chunks(), we'll wind up here again, but
// cur_len will be zero, so the next line will be entirely
// devoted to the long word that we can't handle right now.
}
_wrap_chunks(chunks) {
/*
* _wrap_chunks(chunks : [string]) -> [string]
*
* Wrap a sequence of text chunks and return a list of lines of
* length 'self.width' or less. (If 'break_long_words' is false,
* some lines may be longer than this.) Chunks correspond roughly
* to words and the whitespace between them: each chunk is
* indivisible (modulo 'break_long_words'), but a line break can
* come between any two chunks. Chunks should not have internal
* whitespace; ie. a chunk is either all whitespace or a "word".
* Whitespace chunks will be removed from the beginning and end of
* lines, but apart from that whitespace is preserved.
*/
let lines = []
let indent
if (this.width <= 0) {
throw Error(`invalid width ${this.width} (must be > 0)`)
}
if (this.max_lines !== undefined) {
if (this.max_lines > 1) {
indent = this.subsequent_indent
} else {
indent = this.initial_indent
}
if (indent.length + this.placeholder.trimStart().length > this.width) {
throw Error('placeholder too large for max width')
}
}
// Arrange in reverse order so items can be efficiently popped
// from a stack of chucks.
chunks = chunks.reverse()
while (chunks.length > 0) {
// Start the list of chunks that will make up the current line.
// cur_len is just the length of all the chunks in cur_line.
let cur_line = []
let cur_len = 0
// Figure out which static string will prefix this line.
let indent
if (lines) {
indent = this.subsequent_indent
} else {
indent = this.initial_indent
}
// Maximum width for this line.
let width = this.width - indent.length
// First chunk on line is whitespace -- drop it, unless this
// is the very beginning of the text (ie. no lines started yet).
if (this.drop_whitespace && chunks[chunks.length - 1].trim() === '' && lines.length > 0) {
chunks.pop()
}
while (chunks.length > 0) {
let l = chunks[chunks.length - 1].length
// Can at least squeeze this chunk onto the current line.
if (cur_len + l <= width) {
cur_line.push(chunks.pop())
cur_len += l
// Nope, this line is full.
} else {
break
}
}
// The current line is full, and the next chunk is too big to
// fit on *any* line (not just this one).
if (chunks.length && chunks[chunks.length - 1].length > width) {
this._handle_long_word(chunks, cur_line, cur_len, width)
cur_len = cur_line.map(l => l.length).reduce((a, b) => a + b, 0)
}
// If the last chunk on this line is all whitespace, drop it.
if (this.drop_whitespace && cur_line.length > 0 && cur_line[cur_line.length - 1].trim() === '') {
cur_len -= cur_line[cur_line.length - 1].length
cur_line.pop()
}
if (cur_line) {
if (this.max_lines === undefined ||
lines.length + 1 < this.max_lines ||
(chunks.length === 0 ||
this.drop_whitespace &&
chunks.length === 1 &&
!chunks[0].trim()) && cur_len <= width) {
// Convert current line back to a string and store it in
// list of all lines (return value).
lines.push(indent + cur_line.join(''))
} else {
let had_break = false
while (cur_line) {
if (cur_line[cur_line.length - 1].trim() &&
cur_len + this.placeholder.length <= width) {
cur_line.push(this.placeholder)
lines.push(indent + cur_line.join(''))
had_break = true
break
}
cur_len -= cur_line[-1].length
cur_line.pop()
}
if (!had_break) {
if (lines) {
let prev_line = lines[lines.length - 1].trimEnd()
if (prev_line.length + this.placeholder.length <=
this.width) {
lines[lines.length - 1] = prev_line + this.placeholder
break
}
}
lines.push(indent + this.placeholder.lstrip())
}
break
}
}
}
return lines
}
_split_chunks(text) {
text = this._munge_whitespace(text)
return this._split(text)
}
// -- Public interface ----------------------------------------------
wrap(text) {
/*
* wrap(text : string) -> [string]
*
* Reformat the single paragraph in 'text' so it fits in lines of
* no more than 'self.width' columns, and return a list of wrapped
* lines. Tabs in 'text' are expanded with string.expandtabs(),
* and all other whitespace characters (including newline) are
* converted to space.
*/
let chunks = this._split_chunks(text)
// not implemented in js
//if (this.fix_sentence_endings) {
// this._fix_sentence_endings(chunks)
//}
return this._wrap_chunks(chunks)
}
fill(text) {
/*
* fill(text : string) -> string
*
* Reformat the single paragraph in 'text' to fit in lines of no
* more than 'self.width' columns, and return a new string
* containing the entire wrapped paragraph.
*/
return this.wrap(text).join('\n')
}
}
// -- Convenience interface ---------------------------------------------
function wrap(text, options = {}) {
/*
* Wrap a single paragraph of text, returning a list of wrapped lines.
*
* Reformat the single paragraph in 'text' so it fits in lines of no
* more than 'width' columns, and return a list of wrapped lines. By
* default, tabs in 'text' are expanded with string.expandtabs(), and
* all other whitespace characters (including newline) are converted to
* space. See TextWrapper class for available keyword args to customize
* wrapping behaviour.
*/
let { width = 70, ...kwargs } = options
let w = new TextWrapper(Object.assign({ width }, kwargs))
return w.wrap(text)
}
function fill(text, options = {}) {
/*
* Fill a single paragraph of text, returning a new string.
*
* Reformat the single paragraph in 'text' to fit in lines of no more
* than 'width' columns, and return a new string containing the entire
* wrapped paragraph. As with wrap(), tabs are expanded and other
* whitespace characters converted to space. See TextWrapper class for
* available keyword args to customize wrapping behaviour.
*/
let { width = 70, ...kwargs } = options
let w = new TextWrapper(Object.assign({ width }, kwargs))
return w.fill(text)
}
// -- Loosely related functionality -------------------------------------
let _whitespace_only_re = /^[ \t]+$/mg
let _leading_whitespace_re = /(^[ \t]*)(?:[^ \t\n])/mg
function dedent(text) {
/*
* Remove any common leading whitespace from every line in `text`.
*
* This can be used to make triple-quoted strings line up with the left
* edge of the display, while still presenting them in the source code
* in indented form.
*
* Note that tabs and spaces are both treated as whitespace, but they
* are not equal: the lines " hello" and "\\thello" are
* considered to have no common leading whitespace.
*
* Entirely blank lines are normalized to a newline character.
*/
// Look for the longest leading string of spaces and tabs common to
// all lines.
let margin = undefined
text = text.replace(_whitespace_only_re, '')
let indents = text.match(_leading_whitespace_re) || []
for (let indent of indents) {
indent = indent.slice(0, -1)
if (margin === undefined) {
margin = indent
// Current line more deeply indented than previous winner:
// no change (previous winner is still on top).
} else if (indent.startsWith(margin)) {
// pass
// Current line consistent with and no deeper than previous winner:
// it's the new winner.
} else if (margin.startsWith(indent)) {
margin = indent
// Find the largest common whitespace between current line and previous
// winner.
} else {
for (let i = 0; i < margin.length && i < indent.length; i++) {
if (margin[i] !== indent[i]) {
margin = margin.slice(0, i)
break
}
}
}
}
if (margin) {
text = text.replace(new RegExp('^' + margin, 'mg'), '')
}
return text
}
module.exports = { wrap, fill, dedent }