Class: Text::Format

Class Text::Format |
In: | lib/text/format.rb
Parent: | Object

# Introduction

Text::Format provides the ability to nicely format fixed-width text with knowledge of the writeable space (number of columns), margins, and indentation settings.

Copyright: | Copyright © 2002 - 2003 by Austin Ziegler
Version: | 0.63
Based On: | Perl Text::Format, Copyright © 1998 Gábor Egressy
Licence: | Ruby’s, Perl Artistic, or GPL version 2 (or later)

Methods

== body_indent= center columns= expand first_indent= format format_style= hyphenate_to hyphenator= justify? left_align? left_margin= new paragraphs right_align? right_fill? right_margin= split_rules= tabstop= unexpand

Constants

VERSION | = | '0.63'
ABBREV | = | [ 'Mr', 'Mrs', 'Ms', 'Jr', 'Sr' ]
|  | Local abbreviations. More can be added with Text::Format.abbreviations
LEFT_ALIGN | = | 0
|  | Formatting values
RIGHT_ALIGN | = | 1
RIGHT_FILL | = | 2
JUSTIFY | = | 3
SPLIT_FIXED | = | 1
|  | Word split modes (only applies when #hard_margins is true).
SPLIT_CONTINUATION | = | 2
SPLIT_HYPHENATION | = | 4
SPLIT_CONTINUATION_FIXED | = | SPLIT_CONTINUATION | SPLIT_FIXED
SPLIT_HYPHENATION_FIXED | = | SPLIT_HYPHENATION | SPLIT_FIXED
SPLIT_HYPHENATION_CONTINUATION | = | SPLIT_HYPHENATION | SPLIT_CONTINUATION
SPLIT_ALL | = | SPLIT_HYPHENATION | SPLIT_CONTINUATION | SPLIT_FIXED
LEQ_RE | = | /[.?!]['"]?$/

Attributes

abbreviations | [RW] | Defines the current abbreviations as an array. This is only used if extra_space is turned on. If one is abbreviating "President" as "Pres." (abbreviations = ["Pres"]), then the results of formatting will be as illustrated in the table below:
          extra_space  |  include?        |  !include?
            true       |  Pres. Lincoln   |  Pres.  Lincoln
            false      |  Pres. Lincoln   |  Pres. Lincoln
Default: | `{}`
Used in: | `#format`, `#paragraphs`
body_indent | [R] | The number of spaces to indent all lines after the first line of a paragraph.
                                columns
     <-------------------------------------------------------------->
     <-----------><------><---------------------------><------------>
      left margin  INDENT  text is formatted into here  right margin
Default: | `0`
Used in: | `#format`, `#paragraphs`
columns | [R] | The total width of the format area. The margins, indentation, and text are formatted into this space.
                                COLUMNS
     <-------------------------------------------------------------->
     <-----------><------><---------------------------><------------>
      left margin  indent  text is formatted into here  right margin
Default: | `72`
Used in: | `#format`, `#paragraphs`, `#center`
extra_space | [RW] | Indicates whether sentence terminators should be followed by a single space (`false`), or two spaces (`true`).
Default: | `false`
Used in: | `#format`, `#paragraphs`
first_indent | [R] | The number of spaces to indent the first line of a paragraph.
                                columns
     <-------------------------------------------------------------->
     <-----------><------><---------------------------><------------>
      left margin  INDENT  text is formatted into here  right margin
Default: | `4`
Used in: | `#format`, `#paragraphs`
format_style | [R] | Specifies the format style. Allowable values are: `LEFT_ALIGN` Left justified, ragged right.
         |A paragraph that is|
         |left aligned.|
`RIGHT_ALIGN` Right justified, ragged left.
         |A paragraph that is|
         |     right aligned.|
`RIGHT_FILL` Left justified, right ragged, filled to width by spaces. (Essentially the same as `LEFT_ALIGN` except that lines are padded on the right.)
         |A paragraph that is|
         |left aligned.      |
`JUSTIFY` Fully justified, words filled to width by spaces, except the last line.
         |A paragraph  that|
         |is     justified.|
Default: | `Text::Format::LEFT_ALIGN`
Used in: | `#format`, `#paragraphs`
hard_margins | [RW] | Normally, words larger than the format area will be placed on a line by themselves. Setting this to `true` will force words larger than the format area to be split into one or more "words" each at most the size of the format area. The first line and the original word will be placed into `#split_words`. Note that this will cause the output to look similar to a #format_style of JUSTIFY. (Lines will be filled as much as possible.)
Default: | `false`
Used in: | `#format`, `#paragraphs`
hyphenator | [R] | The object responsible for hyphenating. It must respond to #hyphenate_to(word, size) or #hyphenate_to(word, size, formatter) and return an array of the word split into two parts; if there is a hyphenation mark to be applied, responsibility belongs to the hyphenator object. The size is the MAXIMUM size permitted, including any hyphenation marks. If the #hyphenate_to method has an arity of 3, the formatter will be provided to the method. This allows the hyphenator to make decisions about the hyphenation based on the formatting rules.
Default: | `nil`
Used in: | `#format`, `#paragraphs`
left_margin | [R] | The number of spaces used for the left margin.
                                columns
     <-------------------------------------------------------------->
     <-----------><------><---------------------------><------------>
      LEFT MARGIN  indent  text is formatted into here  right margin
Default: | `0`
Used in: | `#format`, `#paragraphs`, `#center`
nobreak | [RW] | Indicates whether or not the non-breaking space feature should be used.
Default: | `false`
Used in: | `#format`, `#paragraphs`
nobreak_regex | [RW] | A hash which holds the regular expressions on which spaces should not be broken. The hash is set up such that the key is the first word and the value is the second word. For example, if `nobreak_regex` contains the following hash:
      { '^Mrs?\.$' => '\S+$', '^\S+$' => '^(?:S|J)r\.$'}
Then "Mr. Jones", "Mrs. Jones", and "Jones Jr." would not be broken. If this simple matching algorithm indicates that there should not be a break at the current end of line, then a backtrack is done until there are two words on which line breaking is permitted. If two such words are not found, then the end of the line will be broken regardless. If there is a single word on the current line, then no backtrack is done and the word is stuck on the end.
Default: | `{}`
Used in: | `#format`, `#paragraphs`
right_margin | [R] | The number of spaces used for the right margin.
                                columns
     <-------------------------------------------------------------->
     <-----------><------><---------------------------><------------>
      left margin  indent  text is formatted into here  RIGHT MARGIN
Default: | `0`
Used in: | `#format`, `#paragraphs`, `#center`
split_rules | [R] | Specifies the split mode; used only when #hard_margins is set to `true`. Allowable values are: `SPLIT_FIXED` The word will be split at the number of characters needed, with no marking at all.
         repre
         senta
         ion
`SPLIT_CONTINUATION` The word will be split at the number of characters needed, with a C-style continuation character. If a word is the only item on a line and it cannot be split into an appropriate size, SPLIT_FIXED will be used.
          repr       #       esen       #       tati       #       on
`SPLIT_HYPHENATION` The word will be split according to the hyphenator specified in #hyphenator. If there is no #hyphenator specified, works like SPLIT_CONTINUATION. The example is using TeX::Hyphen. If a word is the only item on a line and it cannot be split into an appropriate size, SPLIT_CONTINUATION mode will be used.
          rep-
          re-
          sen-
          ta-
          tion
Default: | `Text::Format::SPLIT_FIXED`
Used in: | `#format`, `#paragraphs`
split_words | [R] | An array of words split during formatting if #hard_margins is set to `true`.
      #split_words << Text::Format::SplitWord.new(word, first, rest)
tabstop | [R] | Indicates the number of spaces that a single tab represents.
Default: | `8`
Used in: | `#expand`, `#unexpand`, `#paragraphs`
tag_paragraph | [RW] | Indicates whether the formatting of paragraphs should be done with tagged paragraphs. Useful only with `#tag_text`.
Default: | `false`
Used in: | `#format`, `#paragraphs`
tag_text | [RW] | The array of text to be placed before each paragraph when `#tag_paragraph` is `true`. When `#format()` is called, only the first element of the array is used. When `#paragraphs` is called, then each entry in the array will be used once, with corresponding paragraphs. If the tag elements are exhausted before the text is exhausted, then the remaining paragraphs will not be tagged. Regardless of indentation settings, a blank line will be inserted between all paragraphs when `#tag_paragraph` is `true`.
Default: | `[]`
Used in: | `#format`, `#paragraphs`
text | [RW] | The text to be manipulated. Note that value is optional, but if the formatting functions are called without values, this text is what will be formatted.
Default: | `[]`
Used in: | All methods

Classes and Modules

Class Text::Format::SplitWord

Public Class methods

new(arg = nil, &block)

This constructor takes advantage of a technique for Ruby object construction introduced by Andy Hunt and Dave Thomas (see reference), where optional values are set using commands in a block.

      Text::Format.new {
          columns         = 72
          left_margin     = 0
          right_margin    = 0
          first_indent    = 4
          body_indent     = 0
          format_style    = Text::Format::LEFT_ALIGN
          extra_space     = false
          abbreviations   = {}
          tag_paragraph   = false
          tag_text        = []
          nobreak         = false
          nobreak_regex   = {}
          tabstop         = 8
          text            = nil
      }

As shown above, `arg` is optional. If `arg` is specified and is a `String`, then arg is used as the default value of `#text`. Alternately, an existing Text::Format object can be used or a Hash can be used. With all forms, a block can be specified.

Reference: | "Object Construction and Blocks" <www.pragmaticprogrammer.com/ruby/articles/insteval.html>

Public Instance methods

==(o)

Compares two Text::Format objects. All settings of the objects are compared except #hyphenator. Generated results (e.g., #split_words) are not compared, either.

columns=(c)

The total width of the format area. The margins, indentation, and text are formatted into this space. The value provided is silently converted to a positive integer.

                                COLUMNS
     <-------------------------------------------------------------->
     <-----------><------><---------------------------><------------>
      left margin  indent  text is formatted into here  right margin

Default: | `72`
Used in: | `#format`, `#paragraphs`, `#center`

left_margin=(left)

The number of spaces used for the left margin. The value provided is silently converted to a positive integer value.

                                columns
     <-------------------------------------------------------------->
     <-----------><------><---------------------------><------------>
      LEFT MARGIN  indent  text is formatted into here  right margin

Default: | `0`
Used in: | `#format`, `#paragraphs`, `#center`

right_margin=(r)

The number of spaces used for the right margin. The value provided is silently converted to a positive integer value.

                                columns
     <-------------------------------------------------------------->
     <-----------><------><---------------------------><------------>
      left margin  indent  text is formatted into here  RIGHT MARGIN

Default: | `0`
Used in: | `#format`, `#paragraphs`, `#center`

first_indent=(f)

The number of spaces to indent the first line of a paragraph. The value provided is silently converted to a positive integer value.

                                columns
     <-------------------------------------------------------------->
     <-----------><------><---------------------------><------------>
      left margin  INDENT  text is formatted into here  right margin

Default: | `4`
Used in: | `#format`, `#paragraphs`

body_indent=(b)

The number of spaces to indent all lines after the first line of a paragraph. The value provided is silently converted to a positive integer value.

                                columns
     <-------------------------------------------------------------->
     <-----------><------><---------------------------><------------>
      left margin  INDENT  text is formatted into here  right margin

Default: | `0`
Used in: | `#format`, `#paragraphs`

hyphenator=(h)

The object responsible for hyphenating. It must respond to #hyphenate_to(word, size) and return an array of the word hyphenated into two parts. The size is the MAXIMUM size permitted, including any hyphenation marks.

Default: | `nil`
Used in: | `#format`, `#paragraphs`

split_rules=(s)

Specifies the split mode; used only when #hard_margins is set to `true`. Allowable values are:

`SPLIT_FIXED`
  The word will be split at the number of characters needed, with no marking at all.

         repre
         senta
         ion

`SPLIT_CONTINUATION`
  The word will be split at the number of characters needed, with a C-style continuation character.

          repr       #       esen       #       tati       #       on

`SPLIT_HYPHENATION`
  The word will be split according to the hyphenator specified in #hyphenator. If there is no #hyphenator specified, works like SPLIT_CONTINUATION. The example is using TeX::Hyphen as the #hyphenator.

          rep-
          re-
          sen-
          ta-
          tion

These values can be bitwise ORed together (e.g., `SPLIT_FIXED | SPLIT_CONTINUATION`) to provide fallback split methods. In the example given, an attempt will be made to split the word using the rules of SPLIT_CONTINUATION; if there is not enough room, the word will be split with the rules of SPLIT_FIXED. These combinations are also available as the following values:

- `SPLIT_CONTINUATION_FIXED`
- `SPLIT_HYPHENATION_FIXED`
- `SPLIT_HYPHENATION_CONTINUATION`
- `SPLIT_ALL`

Default: | `Text::Format::SPLIT_FIXED`
Used in: | `#format`, `#paragraphs`

tabstop=(t)

Indicates the number of spaces that a single tab represents.

Default: | `8`
Used in: | `#expand`, `#unexpand`, `#paragraphs`

format_style=(fs)

Specifies the format style. Allowable values are:

`LEFT_ALIGN`
  Left justified, ragged right.

         |A paragraph that is|
         |left aligned.|

`RIGHT_ALIGN`
  Right justified, ragged left.

         |A paragraph that is|
         |     right aligned.|

`RIGHT_FILL`
  Left justified, right ragged, filled to width by spaces. (Essentially the same as `LEFT_ALIGN` except that lines are padded on the right.)

         |A paragraph that is|
         |left aligned.      |

`JUSTIFY`
  Fully justified, words filled to width by spaces.

         |A paragraph  that|
         |is     justified.|

Default: | `Text::Format::LEFT_ALIGN`
Used in: | `#format`, `#paragraphs`

left_align?()

Indicates that the format style is left alignment.

Default: | `true`
Used in: | `#format`, `#paragraphs`

right_align?()

Indicates that the format style is right alignment.

Default: | `false`
Used in: | `#format`, `#paragraphs`

right_fill?()

Indicates that the format style is right fill.

Default: | `false`
Used in: | `#format`, `#paragraphs`

justify?()

Indicates that the format style is full justification.

Default: | `false`
Used in: | `#format`, `#paragraphs`

hyphenate_to(word, size)

The default implementation of #hyphenate_to implements SPLIT_CONTINUATION.

format(to_wrap = nil)

Formats text into a nice paragraph format. The text is separated into words and then reassembled a word at a time using the settings of this Format object. If a word is larger than the number of columns available for formatting, then that word will appear on the line by itself.

If `to_wrap` is `nil`, then the value of `#text` will be worked on.

paragraphs(to_wrap = nil)

Considers each element of text (provided or internal) as a paragraph. If `#first_indent` is the same as `#body_indent`, then paragraphs will be separated by a single empty line in the result; otherwise, the paragraphs will follow immediately after each other. Uses `#format` to do the heavy lifting.

center(to_center = nil)

Centers the text, preserving empty lines and tabs.

expand(to_expand = nil)

Replaces all tab characters in the text with `#tabstop` spaces.

unexpand(to_unexpand = nil)

Replaces all occurrences of `#tabstop` consecutive spaces with a tab character.