NAME

Lingua::EN::Fathom - readability and general measurements of English text

SYNOPSIS

   use Lingua::EN::Fathom;

   my $text = new Lingua::EN::Fathom; 

   $text->analyse_file("sample.txt");
   
   $text->analyse_block($text_string);
   
   $num_chars       = $text->num_chars;
   $num_words       = $text->num_words;
   $num_sentences   = $text->num_sentences;
   $num_text_lines  = $text->num_text_lines;
   $num_blank_lines = $text->num_blank_lines;
   $num_paragraphs  = $text->num_paragraphs;
   
   
   %words = $text->unique_words;
   foreach $word ( sort keys %words )
   {
      print("$words{$word} :$word\n");
   }
   
   $fog     = $text->fog;
   $flesch  = $text->flesch;
   $kincaid = $text->kincaid;
   
   print($text->report);
   

REQUIRES

Perl, version 5.001 or higher, Lingua::EN::Syllable

DESCRIPTION

This module analyses English text in either a string or file. Totals are then calculated for the number of characters, words, sentences, blank and non blank (text) lines and paragraphs.

Three common readability statistics are also derived, the Fog, Flesch and Kincaid indices.

All of these properties can be accessed through individual methods, or by generating a text report.

METHODS

new

The new method creates an instance of an text object This must be called before any of the following methods are invoked. Note that the object only needs to be created once, and can be reused with new input data.

   my $text = new Lingua::EN::Fathom; 

analyse_file

The analyse_file method takes as input the name of a text file. Various text based statistics are calculated for the file. This method and analyse_block are prerequisites for all the following methods.

analyse_block

The analyse_block method takes as input the name of a text file. Various text based statistics are calculated for the file. This method and analyse_file are prerequisites for all the following methods.

num_chars

Returns the number of characters in the analysed text file or block. This includes characters such as spaces, and punctuation marks.

num_words

Returns the number of words in the analysed text file or block. A word must consist of letters a-z with at least one vowel sound, and optionally an apostrophe or hyphen. Items such as "&, K108, NSW" are not counted as words.

num_sentences

Returns the number of sentences in the analysed text file or block. A sentence is any group of words and non words terminated with a single full stop. Spaces may occur before and after the full stop.

num_text_lines

Returns the number of lines containing some text in the analysed text file or block.

num_blank_lines

Returns the number of lines NOT containing any text in the analysed text file or block.

num_blank_lines

Returns the number of paragraphs in the analysed text file or block.

READABILITY

Three indices of text readability are calcuated. They all meausure complexity as a function of syllables per word and words per sentence. They assume the text is well formed and logical. You could analyse a passage of non-sensical English and find the readability is quite good, provided the words are not too complex and the sentences not too long.

For more information see: http://www.plainlanguage.com/Resources/readability.html

fog

Returns the Fog index for the analysed text file or block.

The Fog index, developed by Robert Gunning, is a well known and simple formula for measuring readability. The index indicates the number of years of formal education a reader of average intelligence would need to read the text once and understand that piece of writing with its word sentence workload.

   18 unreadable
   14 difficult
   12 ideal
   10 acceptable
    8 childish

flesch

Returns the Flesch reading ease score for the analysed text file or block.

This score rates text on a 100 point scale. The higher the score, the easier it is to understand the text. A score of 60 to 70 is considered to be optimal.

kincaid

Returns the Flesch-Kincaid grade level score for the analysed text file or block.

This score rates text on U.S. grade school level. So a score of 8.0 means that the document can be understood by an eighth grader. A score of 7.0 to 8.0 is considered to be optimal.

unique_words

Returns a hash of unique words. The words (in lower case) are held in the hash keys while the number of occurrences are held in the hash values.

SEE ALSO

   Lingua::EN::Syllable
   B::Fathom

POSSIBLE EXTENSIONS

   Analyse many files at once
   Analyse HTML and other formats
   Allow user control over what strictly defines a word
   Provide a density measure of white space to characters 

LIMITATIONS

Common abbreviations such as St. or Pty. Ltd. will trick the module into inflating the number of sentences it finds.

The syllable count provided in Lingua::EN;;syllable is about 90% accurate

Acronyms that contain vowels, like GPO, will be counted as word.

The fog index should exclude proper names

BUGS

COPYRIGHT

Copyright (c) 2000 Kim Ryan. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the Perl Artistic License (see http://www.perl.com/perl/misc/Artistic.html).

AUTHOR

Lingua::EN::Fathom was written by Kim Ryan <kimaryan@ozemail.com.au> in 2000.