# Lingua::EN::Fathom - phpMan

## NAME
    [Lingua::EN::Fathom] - Measure readability of English text

## SYNOPSIS
        use [Lingua::EN::Fathom];

        my $text = [Lingua::EN::Fathom]->new();

        # Analyse contents of a text file
        $text->analyse_file("sample.txt"); # Analyse contents of a text file

        $accumulate = 1;
        # Analyse contents of a text string
        $text->analyse_block($text_string,$accumulate);

        # TO Do, remove repetition
        $num_chars             = $text->num_chars;
        $num_words             = $text->num_words;
        $percent_complex_words = $text->percent_complex_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;
        $syllables_per_word    = $text->syllables_per_word;
        $words_per_sentence    = $text->words_per_sentence;

       # comment needed
        %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.

    A hash of all unique words and the number of times they occur is
    generated.

## 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 = [Lingua::EN::Fathom]->new();

  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. An
    optional argument may be supplied to control accumulation of statistics.
    If set to a non zero value, all statistics are accumulated with each
    successive call.

        $text->analyse_file("sample.txt");

  analyse_block
    The "analyse_block" method takes as input a text string. Various text
    based statistics are calculated for the file. This method and
    "analyse_file" are prerequisites for all the following methods. An
    optional argument may be supplied to control accumulation of statistics.
    If set to a non zero value, all statistics are accumulated with each
    successive call.

        $text->analyse_block($text_str);

  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, NW" are not
    counted as words.

  percent_complex_words
    Returns the percentage of complex words in the analysed text file or
    block. A complex word must consist of three or more syllables. This
    statistic is used to calculate the fog index.

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

  syllables_per_word
    Returns the average number of syllables per word in the analysed text
    file or block.

  words_per_sentence
    Returns the average number of words per sentence in the analysed text
    file or block.

  READABILITY
    Three indices of text readability are calculated. They all measure
    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 nonsensical 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.

      ( words_per_sentence + percent_complex_words ) * 0.4

    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.

       206.835 - (1.015 * words_per_sentence) - (84.6 * syllables_per_word)

    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.

       (11.8 * syllables_per_word) +  (0.39 * words_per_sentence) - 15.59;

    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.

  report
        print($text->report);

    Produces a text based report containing all Fathom statistics for the
    currently analysed text block or file. For example:

    Number of characters : 813 Number of words : 135 Percent of complex
    words : 20.00 Average syllables per word : 1.7704 Number of sentences :
    12 Average words per sentence : 11.2500 Number of text lines : 13 Number
    of blank lines : 8 Number of paragraphs : 4

    READABILITY INDICES

    Fog : 12.5000 Flesch : 45.6429 Flesch-Kincaid : 9.6879

    The return value is a string containing the report contents

## SEE ALSO
    [Lingua::EN::Syllable],[Lingua::EN::Sentence],[B::Fathom]

## POSSIBLE EXTENSIONS
       Count white space and punctuation characters
       Allow user control over what strictly defines a word

## LIMITATIONS
    The syllable count provided in [Lingua::EN::Syllable] is about 90%
    accurate

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

    The fog index should exclude proper names

## BUGS
    None known

## AUTHOR
    [Lingua::EN::Fathom] was written by Kim Ryan <kimryan at cpan dot org>.

## COPYRIGHT AND LICENSE
    Copyright (c) 2018 Kim Ryan. All rights reserved.

    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

