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

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 (c) 2002 - 2003 by Austin Ziegler
Version:0.61
Based On:Perl Text::Format, Copyright (c) 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   
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) 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
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.