HTML::TextToHTML(3pm)

NAME
HTML::TextToHTML - convert plain text file to HTML.

VERSION
version 3.0

SYNOPSIS
  From the command line:

    txt2html I<arguments>

  From Scripts:

    use HTML::TextToHTML;

    # create a new object
    my $conv = new HTML::TextToHTML();

    # convert a file
    $conv->txt2html(infile=>[$text_file],
                     outfile=>$html_file,
                     title=>"Wonderful Things",
                     mail=>1,
      ]);

    # reset arguments
    $conv->args(infile=>[], mail=>0);

    # convert a string
    $newstring = $conv->process_chunk($mystring)

DESCRIPTION
HTML::TextToHTML converts plain text files to HTML. The txt2html script uses this module to do the same from the command-line.

It supports headings, tables, lists, simple character markup, and hyperlinking, and is highly customizable. It recognizes some of the apparent structure of the source document (mostly whitespace and typographic layout), and attempts to mark that structure explicitly using HTML. The purpose for this tool is to provide an easier way of converting existing text documents to HTML format, giving something nicer than just whapping the text into a big PRE block.

  History
The original txt2html script was written by Seth Golub (see http://www.aigeek.com/txt2html/), and converted to a perl module by Kathryn Andersen (see http://www.katspace.com/tools/text_to_html/) and made into a sourceforge project by Sun Tong (see http://sourceforge.net/projects/txt2html/). Earlier versions of the HTML::TextToHTML module called the included script texthyper so as not to clash with the original txt2html script, but now the projects have all been merged. UPDATING: currently, the project is available on GitHub at https://github.com/resurrecting-open-source-projects/txt2html

OPTIONS
All arguments can be set when the object is created, and further options can be set when calling the actual txt2html method. Arguments to methods can take a hash of arguments.

Note that all option-names must match exactly -- no abbreviations are allowed. The argument-keys are expected to have values matching those required for that argument -- whether that be a boolean, a string, a reference to an array or a reference to a hash. These will replace any value for that argument that might have been there before.

append_file
        append_file=>I<filename>

    If you want something appended by default, put the filename here. The appended text will not be processed at all, so make sure it's plain text or correct HTML. i.e. do not have things like:
        Mary Andersen <kitty@example.com> but instead, have:
        Mary Andersen &lt;kitty@example.com&gt;

    (default: nothing)

append_head
        append_head=>I<filename>

    If you want something appended to the head by default, put the filename here. The appended text will not be processed at all, so make sure it's plain text or correct HTML. i.e. do not have things like:
        Mary Andersen <kitty@example.com> but instead, have:
        Mary Andersen &lt;kitty@example.com&gt;

    (default: nothing)

body_deco
        body_deco=>I<string>

    Body decoration string: a string to be added to the BODY tag so that one can set attributes to the BODY (such as class, style, bgcolor etc) For example, "class='withimage'".

bold_delimiter
        bold_delimiter=>I<string>

    This defines what character (or string) is taken to be the delimiter of text which is to be interpreted as bold (that is, to be given a STRONG tag). If this is empty, then no bolding of text will be done. (default: #)

bullets
        bullets=>I<string>

    This defines what single characters are taken to be "bullet" characters for unordered lists. Note that because this is used as a character class, if you use '-' it must come first. (default:-=o*\267)

bullets_ordered
        bullets_ordered=>I<string>

    This defines what single characters are taken to be "bullet" placeholder characters for ordered lists. Ordered lists are normally marked by a number or letter followed by '.' or ')' or ']' or ':'. If an ordered bullet is used, then it simply indicates that this is an ordered list, without giving explicit numbers.

    Note that because this is used as a character class, if you use '-' it must come first. (default:nothing)

caps_tag
        caps_tag=>I<tag>

    Tag to put around all-caps lines (default: STRONG) If an empty tag is given, then no tag will be put around all-caps lines.

custom_heading_regexp
        custom_heading_regexp=>\@custom_headings

    Add patterns for headings. Header levels are assigned by regexp in the order seen in the input text. When a line matches a custom header regexp, it is tagged as a header. If it's the first time that particular regexp has matched, the next available header level is associated with it and applied to the line. Any later matches of that regexp will use the same header level. Therefore, if you want to match numbered header lines, you could use something like this:

        my @custom_headings = ('^ *\d+\. \w+',
                               '^ *\d+\.\d+\. \w+',
                               '^ *\d+\.\d+\.\d+\. \w+');

        ...
            custom_heading_regexp=>\@custom_headings,
        ...

    Then lines like

                    " 1. Examples "
                    " 1.1. Things"
                and " 4.2.5. Cold Fusion"

    Would be marked as H1, H2, and H3 (assuming they were found in that order, and that no other header styles were encountered). If you prefer that the first one specified always be H1, the second always be H2, the third H3, etc, then use the "explicit_headings" option.

    This expects a reference to an array of strings.

    (default: none)

default_link_dict
        default_link_dict=>I<filename>

    The name of the default "user" link dictionary. (default: "$ENV{'HOME'}/.txt2html.dict" -- this is the same as for the txt2html script. If there is no $ENV{HOME} then it is just '.txt2html.dict')

demoronize
        demoronize=>1

    Convert Microsoft-generated character codes that are non-ISO codes into something more reasonable. (default:true)

doctype
        doctype=>I<doctype>

    This gets put in the DOCTYPE field at the top of the document, unless it's empty.

    Default : '-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd'

    If xhtml is true, the contents of this is ignored, unless it's empty, in which case no DOCTYPE declaration is output.

eight_bit_clean
        eight_bit_clean=>1

    If false, convert Latin-1 characters to HTML entities. If true, this conversion is disabled; also "demoronize" is set to false, since this also changes 8-bit characters. (default: false)

escape_HTML_chars
        escape_HTML_chars=>1

    turn & < > into &amp; &gt; &lt; (default: true)

explicit_headings
        explicit_headings=>1

    Don't try to find any headings except the ones specified in the --custom_heading_regexp option. Also, the custom headings will not be assigned levels in the order they are encountered in the document, but in the order they are specified on the custom_heading_regexp option. (default: false)

extract
        extract=>1

    Extract Mode; don't put HTML headers or footers on the result, just the plain HTML (thus making the result suitable for inserting into another document (or as part of the output of a CGI script). (default: false)

hrule_min
        hrule_min=>I<n>

    Min number of ---s for an HRule. (default: 4)

indent_width
        indent_width=>I<n>

    Indents this many spaces for each level of a list. (default: 2)

indent_par_break
        indent_par_break=>1

    Treat paragraphs marked solely by indents as breaks with indents. That is, instead of taking a three-space indent as a new paragraph, put in a <BR> and three non-breaking spaces instead. (see also --preserve_indent) (default: false)

infile
        infile=>\@my_files
        infile=>['chapter1.txt', 'chapter2.txt']

    The name of the input file(s). This expects a reference to an array of filenames.

    The special filename '-' designates STDIN.

    See also "inhandle" and "instring".

    (default:-)

inhandle
        inhandle=>\@my_handles
        inhandle=>[\*MYINHANDLE, \*STDIN]

    An array of input filehandles; use this instead of "infile" or "instring" to use a filehandle or filehandles as input.

instring
        instring=>\@my_strings
        instring=>[$string1, $string2]

    An array of input strings; use this instead of "infile" or "inhandle" to use a string or strings as input.

italic_delimiter
        italic_delimiter=>I<string>

    This defines what character (or string) is taken to be the delimiter of text which is to be interpreted as italic (that is, to be given a EM tag). If this is empty, no italicising of text will be done. (default: *)

underline_delimiter
        underline_delimiter=>I<string>

    This defines what character (or string) is taken to be the delimiter of text which is to be interpreted as underlined (that is, to be given a U tag). If this is empty, no underlining of text will be done. (default: _)

links_dictionaries
        links_dictionaries=>\@my_link_dicts
        links_dictionaries=>['url_links.dict', 'format_links.dict']

    File(s) to use as a link-dictionary. There can be more than one of these. These are in addition to the Global Link Dictionary and the User Link Dictionary. This expects a reference to an array of filenames.

link_only
        link_only=>1

    Do no escaping or marking up at all, except for processing the links dictionary file and applying it. This is useful if you want to use the linking feature on an HTML document. If the HTML is a complete document (includes HTML,HEAD,BODY tags, etc) then you'll probably want to use the --extract option also. (default: false)

lower_case_tags
         lower_case_tags=>1

    Force all tags to be in lower-case.

mailmode
        mailmode=>1

    Deal with mail headers & quoted text. The mail header paragraph is given the class 'mail_header', and mail-quoted text is given the class 'quote_mail'. (default: false)

make_anchors
        make_anchors=>0

    Should we try to make anchors in headings? (default: true)

make_links
        make_links=>0

    Should we try to build links? If this is false, then the links dictionaries are not consulted and only structural text-to-HTML conversion is done. (default: true)

make_tables
        make_tables=>1

    Should we try to build tables? If true, spots tables and marks them up appropriately. See "Input File Format" for information on how tables should be formatted.

    This overrides the detection of lists; if something looks like a table, it is taken as a table, and list-checking is not done for that paragraph.

    (default: false)

min_caps_length
        min_caps_length=>I<n>

    min sequential CAPS for an all-caps line (default: 3)

outfile
        outfile=>I<filename>

    The name of the output file. If it is "-" then the output goes to Standard Output. (default: - )

outhandle
    The output filehandle; if this is given then the output goes to this filehandle instead of to the file given in "outfile".

par_indent
        par_indent=>I<n>

    Minimum number of spaces indented in first lines of paragraphs.
      Only used when there's no blank line preceding the new paragraph. (default: 2)

preformat_trigger_lines
        preformat_trigger_lines=>I<n>

    How many lines of preformatted-looking text are needed to switch to <PRE>
              <= 0 : Preformat entire document
                 1 : one line triggers
              >= 2 : two lines trigger

    (default: 2)

endpreformat_trigger_lines
        endpreformat_trigger_lines=>I<n>

    How many lines of unpreformatted-looking text are needed to switch from <PRE>
               <= 0 : Never preformat within document
                  1 : one line triggers
               >= 2 : two lines trigger (default: 2)

    NOTE for preformat_trigger_lines and endpreformat_trigger_lines: A zero takes precedence. If one is zero, the other is ignored. If both are zero, entire document is preformatted.

preformat_start_marker
        preformat_start_marker=>I<regexp>

    What flags the start of a preformatted section if --use_preformat_marker is true.

    (default: "^(:?(:?&lt;)|<)PRE(:?(:?&gt;)|>)\$")

preformat_end_marker
        preformat_end_marker=>I<regexp>

    What flags the end of a preformatted section if --use_preformat_marker is true.

    (default: "^(:?(:?&lt;)|<)/PRE(:?(:?&gt;)|>)\$")

preformat_whitespace_min
        preformat_whitespace_min=>I<n>

    Minimum number of consecutive whitespace characters to trigger normal preformatting. NOTE: Tabs are expanded to spaces before this check is made. That means if tab_width is 8 and this is 5, then one tab may be expanded to 8 spaces, which is enough to trigger preformatting. (default: 5)

prepend_file
        prepend_file=>I<filename>

    If you want something prepended to the processed body text, put the filename here. The prepended text will not be processed at all, so make sure it's plain text or correct HTML.

    (default: nothing)

preserve_indent
        preserve_indent=>1

    Preserve the first-line indentation of paragraphs marked with indents by replacing the spaces of the first line with non-breaking spaces. (default: false)

short_line_length
        short_line_length=>I<n>

    Lines this short (or shorter) must be intentionally broken and are kept that short. (default: 40)

style_url
        style_url=>I<url>

    This gives the URL of a stylesheet; a LINK tag will be added to the output.

tab_width
        tab_width=>I<n>

    How many spaces equal a tab? (default: 8)

table_type
        table_type=>{ ALIGN=>0, PGSQL=>0, BORDER=>1, DELIM=>0 }

    This determines which types of tables will be recognised when "make_tables" is true. The possible types are ALIGN, PGSQL, BORDER and DELIM. (default: all types are true)

title
        title=>I<title>

    You can specify a title. Otherwise it will use a blank one. (default: nothing)

titlefirst
        titlefirst=>1

    Use the first non-blank line as the title. (See also "title")

underline_length_tolerance
        underline_length_tolerance=>I<n>

    How much longer or shorter can underlines be and still be underlines? (default: 1)

underline_offset_tolerance
        underline_offset_tolerance=>I<n>

    How far offset can underlines be and still be underlines? (default: 1)

unhyphenation
        unhyphenation=>0

    Enables unhyphenation of text. (default: true)

use_mosaic_header
        use_mosaic_header=>1

    Use this option if you want to force the heading styles to match what Mosaic outputs. (Underlined with "***"s is H1, with "==="s is H2, with "+++" is H3, with "---" is H4, with "~~~" is H5 and with "..." is H6) This was the behavior of txt2html up to version 1.10. (default: false)

use_preformat_marker
        use_preformat_marker=>1

    Turn on preformatting when encountering "<PRE>" on a line by itself, and turn it off when there's a line containing only "</PRE>". When such preformatted text is detected, the PRE tag will be given the class 'quote_explicit'. (default: off)

xhtml
        xhtml=>1

    Try to make the output conform to the XHTML standard, including closing all open tags and marking empty tags correctly. This turns on --lower_case_tags and overrides the --doctype option. Note that if you add a header or a footer file, it is up to you to make it conform; the header/footer isn't touched by this. Likewise, if you make link-dictionary entries that break XHTML, then this won't fix them, except to the degree of putting all tags into lower-case.

    (default: true)

DEBUGGING
There are global variables for setting types and levels of debugging. These should only be used by developers.

$HTML::TextToHTML::Debug
    $HTML::TextToHTML::Debug = 1;

    Enable copious debugging output. (default: false)

$HTML::TextToHTML::DictDebug
        $HTML::TextToHTML::DictDebug = I<n>;

    Debug mode for link dictionaries. Bitwise-Or what you want to see:

              1: The parsing of the dictionary
              2: The code that will make the links
              4: When each rule matches something
              8: When each tag is created

    (default: 0)

METHODS

  new
    $conv = new HTML::TextToHTML()

    $conv = new HTML::TextToHTML(titlefirst=>1,
        ...
    );

Create a new object with new. If arguments are given, these arguments will be used in invocations of other methods.

See "OPTIONS" for the possible values of the arguments.

  args
    $conv->args(short_line_length=>60,
        titlefirst=>1,
        ....
    );

Updates the current arguments/options of the HTML::TextToHTML object. Takes hash of arguments, which will be used in invocations of other methods. See "OPTIONS" for the possible values of the arguments.

  process_chunk
$newstring = $conv->process_chunk($mystring);

Convert a string to a HTML fragment. This assumes that this string is at the least, a single paragraph, but it can contain more than that. This returns the processed string. If you want to pass arguments to alter the behaviour of this conversion, you need to do that earlier, either when you create the object, or with the "args" method.

    $newstring = $conv->process_chunk($mystring,
                            close_tags=>0);

If there are open tags (such as lists) in the input string, process_chunk will automatically close them, unless you specify not to, with the close_tags option.

    $newstring = $conv->process_chunk($mystring,
                            is_fragment=>1);

If you want this string to be treated as a fragment, and not assumed to be a paragraph, set is_fragment to true. If there is more than one paragraph in the string (ie it contains blank lines) then this option will be ignored.

  process_para
$newstring = $conv->process_para($mystring);

Convert a string to a HTML fragment. This assumes that this string is at the most a single paragraph, with no blank lines in it. If you don't know whether your string will contain blank lines or not, use the "process_chunk" method instead.

This returns the processed string. If you want to pass arguments to alter the behaviour of this conversion, you need to do that earlier, either when you create the object, or with the "args" method.

    $newstring = $conv->process_para($mystring,
                            close_tags=>0);

If there are open tags (such as lists) in the input string, process_para will automatically close them, unless you specify not to, with the close_tags option.

    $newstring = $conv->process_para($mystring,
                            is_fragment=>1);

If you want this string to be treated as a fragment, and not assumed to be a paragraph, set is_fragment to true.

  txt2html
    $conv->txt2html(%args);

Convert a text file to HTML. Takes a hash of arguments. See "OPTIONS" for the possible values of the arguments. Arguments which have already been set with new or args will remain as they are, unless they are overridden.

PRIVATE METHODS
These are methods used internally, only of interest to developers.

  init_our_data
$self->init_our_data();

Initializes the internal object data.

  deal_with_options
$self->deal_with_options();

do extra processing related to particular options

  escape
$newtext = escape($text);

Escape & < and >

  demoronize_char
$newtext = demoronize_char($text);

Convert Microsoft character entities into characters.

Added by Alan Jackson, alan at ajackson dot org, and based on the demoronize script by John Walker, http://www.fourmilab.ch/

  demoronize_code
$newtext = demoronize_code($text);

convert Microsoft character entities into HTML code

  get_tag
$tag = $self->get_tag($in_tag);

$tag = $self->get_tag($in_tag,
    tag_type=>TAG_START,
    inside_tag=>'');

output the tag wanted (add the <> and the / if necessary) - output in lower or upper case - do tag-related processing options:
  tag_type=>TAG_START | tag_type=>TAG_END | tag_type=>TAG_EMPTY
  (default start)
  inside_tag=>string (default empty)

  close_tag
$tag = $self->close_tag($in_tag);

close the open tag

  hrule
   $self->hrule(para_lines_ref=>$para_lines,
             para_action_ref=>$para_action,
             ind=>0);

Deal with horizontal rules.

  shortline
    $self->shortline(line_ref=>$line_ref,
                     line_action_ref=>$line_action_ref,
                     prev_ref=>$prev_ref,
                     prev_action_ref=>$prev_action_ref,
                     prev_line_len=>$prev_line_len);

Deal with short lines.

  is_mailheader
    if ($self->is_mailheader(rows_ref=>$rows_ref))
    {
        ...
    }

Is this a mailheader line?

  mailheader
    $self->mailheader(rows_ref=>$rows_ref);

Deal with a mailheader.

  mailquote
    $self->mailquote(line_ref=>$line_ref,
                     line_action_ref=>$line_action_ref,
                     prev_ref=>$prev_ref,
                     prev_action_ref=>$prev_action_ref,
                     next_ref=>$next_ref);

Deal with quoted mail.

  subtract_modes
    $newvector = subtract_modes($vector, $mask);

Subtracts modes listed in $mask from $vector.

  paragraph
    $self->paragraph(line_ref=>$line_ref,
                     line_action_ref=>$line_action_ref,
                     prev_ref=>$prev_ref,
                     prev_action_ref=>$prev_action_ref,
                     line_indent=>$line_indent,
                     prev_indent=>$prev_indent,
                     is_fragment=>$is_fragment,
                     ind=>$ind);

Detect paragraph indentation.

  listprefix
    ($prefix, $number, $rawprefix, $term) = $self->listprefix($line);

Detect and parse a list item.

  startlist
    $self->startlist(prefix=>$prefix,
                     number=>0,
                     rawprefix=>$rawprefix,
                     term=>$term,
                     para_lines_ref=>$para_lines_ref,
                     para_action_ref=>$para_action_ref,
                     ind=>0,
                     prev_ref=>$prev_ref,
                     total_prefix=>$total_prefix);

Start a list.

  endlist
    $self->endlist(num_lists=>0,
        prev_ref=>$prev_ref,
        line_action_ref=>$line_action_ref);

End N lists

  continuelist
    $self->continuelist(para_lines_ref=>$para_lines_ref,
                        para_action_ref=>$para_action_ref,
                        ind=>0,
                        term=>$term);

Continue a list.

  liststuff
    $self->liststuff(para_lines_ref=>$para_lines_ref,
                     para_action_ref=>$para_action_ref,
                     para_line_indent_ref=>$para_line_indent_ref,
                     ind=>0,
                     prev_ref=>$prev_ref);

Process a list (higher-level method).

  get_table_type
    $table_type = $self->get_table_type(rows_ref=>$rows_ref,
                                        para_len=>0);

Figure out the table type of this table, if any

  is_aligned_table
    if ($self->is_aligned_table(rows_ref=>$rows_ref, para_len=>0))
    {
        ...
    }

Check if the given paragraph-array is an aligned table

  is_pgsql_table
    if ($self->is_pgsql_table(rows_ref=>$rows_ref, para_len=>0))
    {
        ...
    }

Check if the given paragraph-array is a Postgresql table (the ascii format produced by Postgresql)

A PGSQL table can start with an optional table-caption,

    then it has a row of column headings separated by |
    then it has a row of ------+-----
    then it has one or more rows of column values separated by |
    then it has a row-count (N rows)

  is_border_table
    if ($self->is_border_table(rows_ref=>$rows_ref, para_len=>0))
    {
        ...
    }

Check if the given paragraph-array is a Border table.

A BORDER table can start with an optional table-caption,

    then it has a row of +------+-----+
    then it has a row of column headings separated by |
    then it has a row of +------+-----+
    then it has one or more rows of column values separated by |
    then it has a row of +------+-----+

  is_delim_table
    if ($self->is_delim_table(rows_ref=>$rows_ref, para_len=>0))
    {
        ...
    }

Check if the given paragraph-array is a Delimited table.

A DELIM table can start with an optional table-caption, then it has at least two rows which start and end and are punctuated by a non-alphanumeric delimiter.

    | val1 | val2 |
    | val3 | val4 |

  tablestuff
    $self->tablestuff(table_type=>0,
                      rows_ref=>$rows_ref,
                      para_len=>0);

Process a table.

  make_aligned_table
    $self->make_aligned_table(rows_ref=>$rows_ref,
                              para_len=>0);

Make an Aligned table.

  make_pgsql_table
    $self->make_pgsql_table(rows_ref=>$rows_ref,
                              para_len=>0);

Make a PGSQL table.

  make_border_table
    $self->make_border_table(rows_ref=>$rows_ref,
                             para_len=>0);

Make a BORDER table.

  make_delim_table
    $self->make_delim_table(rows_ref=>$rows_ref,
                            para_len=>0);

Make a Delimited table.

  is_preformatted
    if ($self->is_preformatted($line))
    {
        ...
    }

Returns true if the passed string is considered to be preformatted.

  split_end_explicit_preformat
    $front = $self->split_end_explicit_preformat(para_ref=>$para_ref);

Modifies the given string, and returns the front preformatted part.

  endpreformat
    $self->endpreformat(para_lines_ref=>$para_lines_ref,
                        para_action_ref=>$para_action_ref,
                        ind=>0,
                        prev_ref=>$prev_ref);

End a preformatted section.

  preformat
    $self->preformat(mode_ref=>$mode_ref,
                     line_ref=>$line_ref,
                     line_action_ref=>$line_action_ref,
                     prev_ref=>$prev_ref,
                     next_ref=>$next_ref,
                     prev_action_ref);

Detect and process a preformatted section.

  make_new_anchor
    $anchor = $self->make_new_anchor($heading_level);

Make a new anchor.

  anchor_mail
    $self->anchor_mail($line_ref);

Make an anchor for a mail section.

  anchor_heading
    $self->anchor_heading($heading_level, $line_ref);

Make an anchor for a heading.

  heading_level
    $self->heading_level($style);

Add a new heading style if this is a new heading style.

  is_ul_list_line
    if ($self->is_ul_list_line($line))
    {
        ...
    }

Tests if this line starts a UL list item.

  is_heading
    if ($self->is_heading(line_ref=>$line_ref, next_ref=>$next_ref))
    {
        ...
    }

Tests if this line is a heading. Needs to take account of the next line, because a standard heading is defined by "underlining" the text of the heading.

  heading
    $self->heading(line_ref=>$line_ref,
        next_ref=>$next_ref);

Make a heading. Assumes is_heading is true.

  is_custom_heading
    if ($self->is_custom_heading($line))
    {
        ...
    }

Check if the given line matches a custom heading.

  custom_heading
    $self->custom_heading(line_ref=>$line_ref);

Make a custom heading. Assumes is_custom_heading is true.

  unhyphenate_para
    $self->unhyphenate_para($para_ref);

Join up hyphenated words that are split across lines.

  tagline
    $self->tagline($tag, $line_ref);

Put the given tag around the given line.

  iscaps
    if ($self->iscaps($line))
    {
        ...
    }

Check if a line is all capitals.

  caps
    $self->caps(line_ref=>$line_ref,
                line_action_ref=>$line_action_ref);

Detect and deal with an all-caps line.

  do_delim
    $self->do_delim(line_ref=>$line_ref,
                    line_action_ref=>$line_action_ref,
                    delim=>'*',
                    tag=>'STRONG');

Deal with a line which has words delimited by the given delimiter; this is used to deal with italics, bold and underline formatting.

  glob2regexp
    $regexp = glob2regexp($glob);

Convert very simple globs to regexps

  add_regexp_to_links_table
    $self->add_regexp_to_links_table(label=>$label,
                                     pattern=>$pattern,
                                     url=>$url,
                                     switches=>$switches);

Add the given regexp "link definition" to the links table.

  add_literal_to_links_table
    $self->add_literal_to_links_table(label=>$label,
                                      pattern=>$pattern,
                                      url=>$url,
                                      switches=>$switches);

Add the given literal "link definition" to the links table.

  add_glob_to_links_table
    $self->add_glob_to_links_table(label=>$label,
                                   pattern=>$pattern,
                                   url=>$url,
                                   switches=>$switches);

Add the given glob "link definition" to the links table.

  parse_dict
    $self->parse_dict($dictfile, $dict);

Parse the dictionary file. (see also load_dictionary_links, for things that were stripped)

  setup_dict_checking
    $self->setup_dict_checking();

Set up the dictionary checking.

  in_link_context
    if ($self->in_link_context($match, $before))
    {
        ...
    }

Check if we are inside a link (<a ...>); certain kinds of substitution are not allowed here.

  apply_links
    $self->apply_links(para_ref=>$para_ref,
                       para_action_ref=>$para_action_ref);

Apply links and formatting to this paragraph.

  check_dictionary_links
    $self->check_dictionary_links(line_ref=>$line_ref,
                                  line_action_ref=>$line_action_ref);

Check (and alter if need be) the bits in this line matching the patterns in the link dictionary.

  load_dictionary_links
    $self->load_dictionary_links();

Load the dictionary links.

  do_file_start
    $self->do_file_start($outhandle, $para);

Extra stuff needed for the beginning: HTML headers, and prepending a file if desired.

  do_init_call
    $self->do_init_call();

Certain things, like reading link dictionaries, need to be done only once.

FILE FORMATS
There are two files which are used which can affect the outcome of the conversion. One is the link dictionary, which contains patterns (of how to recognise http links and other things) and how to convert them. The other is, naturally, the format of the input file itself.

  Link Dictionary
A link dictionary file contains patterns to match, and what to convert them to. It is called a "link" dictionary because it was intended to be something which defined what a href link was, but it can be used for more than that. However, if you wish to define your own links, it is strongly advised to read up on regular expressions (regexes) because this relies heavily on them.

The file consists of comments (which are lines starting with #) and blank lines, and link entries. Each entry consists of a regular expression, a -> separator (with optional flags), and a link "result".

In the simplest case, with no flags, the regular expression defines the pattern to look for, and the result says what part of the regular expression is the actual link, and the link which is generated has the href as the link, and the whole matched pattern as the visible part of the link. The first character of the regular expression is taken to be the separator for the regex, so one could either use the traditional / separator, or something else such as | (which can be helpful with URLs which are full of / characters).

So, for example, an ftp URL might be defined as:

    |ftp:[\w/\.:+\-]+|      -> $&

This takes the whole pattern as the href, and the resultant link has the same thing in the href as in the contents of the anchor.

But sometimes the href isn't the whole pattern.

    /&lt;URL:\s*(\S+?)\s*&gt;/ --> $1

With the above regex, a () grouping marks the first subexpression, which is represented as $1 (rather than $& the whole expression). This entry matches a URL which was marked explicitly as a URL with the pattern <URL:foo> (note the &lt; is shown as the entity, not the actual character. This is because by the time the links dictionary is checked, all such things have already been converted to their HTML entity forms, unless, of course, the escape_HTML_chars option was turned off) This would give us a link in the form <A HREF="foo">&lt;URL:foo&gt;</A>

The h flag

However, if we want more control over the way the link is constructed, we can construct it ourself. If one gives the h flag, then the "result" part of the entry is taken not to contain the href part of the link, but the whole link.

For example, the entry:

    /&lt;URL:\s*(\S+?)\s*&gt;/ -h-> <A HREF="$1">$1</A>

will take <URL:foo> and give us <A HREF="foo">foo</A>

However, this is a very powerful mechanism, because it can be used to construct custom tags which aren't links at all. For example, to flag *italicised words* the following entry will surround the words with EM tags.

    /\B\*([a-z][a-z -]*[a-z])\*\B/ -hi-> <EM>$1</EM>

The i flag

This turns on ignore case in the pattern matching.

The e flag

This turns on execute in the pattern substitution. This really only makes sense if h is turned on too. In that case, the "result" part of the entry is taken as perl code to be executed, and the result of that code is what replaces the pattern.

The o flag

This marks the entry as a once-only link. This will convert the first instance of a matching pattern, and ignore any others further on.

For example, the following pattern will take the first mention of HTML::TextToHTML and convert it to a link to the module's home page.

    "HTML::TextToHTML"  -io-> http://www.katspace.com/tools/text_to_html/

  Input File Format
For the most part, this module tries to use intuitive conventions for determining the structure of the text input. Unordered lists are marked by bullets; ordered lists are marked by numbers or letters; in either case, an increase in indentation marks a sub-list contained in the outer list.

Headers (apart from custom headers) are distinguished by "underlines" underneath them; headers in all-capitals are distinguished from those in mixed case. All headers, both normal and custom headers, are expected to start at the first line in a "paragraph".

In other words, the following is a header:

    I am Head Man
    -------------

But the following does not have a header:

    I am not a head Man, man
    I am Head Man
    -------------

Tables require a more rigid convention. A table must be marked as a separate paragraph, that is, it must be surrounded by blank lines. Tables come in different types. For a table to be parsed, its --table_type option must be on, and the --make_tables option must be true.

ALIGN Table Type

Columns must be separated by two or more spaces (this prevents accidental incorrect recognition of a paragraph where interword spaces happen to line up). If there are two or more rows in a paragraph and all rows share the same set of (two or more) columns, the paragraph is assumed to be a table. For example

    -e  File exists.
    -z  File has zero size.
    -s  File has nonzero size (returns size).

becomes

    <table>
    <tr><td>-e</td><td>File exists.</td></tr>
    <tr><td>-z</td><td>File has zero size.</td></tr>
    <tr><td>-s</td><td>File has nonzero size (returns size).</td></tr>
    </table>

This guesses for each column whether it is intended to be left, centre or right aligned.

BORDER Table Type

This table type has nice borders around it, and will be rendered with a border, like so:

    +---------+---------+
    | Column1 | Column2 |
    +---------+---------+
    | val1    | val2    |
    | val3    | val3    |
    +---------+---------+

The above becomes

    <table border="1">
    <thead><tr><th>Column1</th><th>Column2</th></tr></thead>
    <tbody>
    <tr><td>val1</td><td>val2</td></tr>
    <tr><td>val3</td><td>val3</td></tr>
    </tbody>
    </table>

It can also have an optional caption at the start.

         My Caption
    +---------+---------+
    | Column1 | Column2 |
    +---------+---------+
    | val1    | val2    |
    | val3    | val3    |
    +---------+---------+

PGSQL Table Type

This format of table is what one gets from the output of a Postgresql query.

     Column1 | Column2
    ---------+---------
     val1    | val2
     val3    | val3
    (2 rows)

This can also have an optional caption at the start. This table is also rendered with a border and table-headers like the BORDER type.

DELIM Table Type

This table type is delimited by non-alphanumeric characters, and has to have at least two rows and two columns before it's recognised as a table.

This one is delimited by the '| character:

    | val1  | val2  |
    | val3  | val3  |

But one can use almost any suitable character such as : # $ % + and so on. This is clever enough to figure out what you are using as the delimiter if you have your data set up like a table. Note that the line has to both begin and end with the delimiter, as well as using it to separate values.

This can also have an optional caption at the start.

EXAMPLES
    use HTML::TextToHTML;

  Create a new object
    my $conv = new HTML::TextToHTML();

    my $conv = new HTML::TextToHTML(title=>"Wonderful Things",
                            default_link_dict=>$my_link_file,
      );

  Add further arguments
    $conv->args(short_line_length=>60,
               preformat_trigger_lines=>4,
               caps_tag=>"strong",
      );

  Convert a file
    $conv->txt2html(infile=>[$text_file],
                     outfile=>$html_file,
                     title=>"Wonderful Things",
                     mail=>1
      );

  Make a pipleline
    open(IN, "ls |") or die "could not open!";
    $conv->txt2html(inhandle=>[\*IN],
                     outfile=>'-',
      );

NOTES

•   If the underline used to mark a header is off by more than 1, then that part of the text will not be picked up as a header unless you change the value of --underline_length_tolerance and/or --underline_offset_tolerance. People tend to forget this.

REQUIRES
HTML::TextToHTML requires Perl 5.8.1 or later.

For installation, it needs:

    Module::Build

The txt2html script needs:

    Getopt::Long
    Getopt::ArgvFile
    Pod::Usage
    File::Basename

For testing, it also needs:

    Test::More

For debugging, it also needs:

    YAML::Syck

INSTALLATION
Make sure you have the dependencies installed first! (see REQUIRES above)

Some of those modules come standard with more recent versions of perl, but I thought I'd mention them anyway, just in case you may not have them.

If you don't know how to install these, try using the CPAN module, an easy way of auto-installing modules from the Comprehensive Perl Archive Network, where the above modules reside. Do "perldoc perlmodinstall" or "perldoc CPAN" for more information.

To install this module type the following:

   perl Build.PL
   ./Build
   ./Build test
   ./Build install

Or, if you're on a platform (like DOS or Windows) that doesn't like the "./" notation, you can do this:

   perl Build.PL
   perl Build
   perl Build test
   perl Build install

In order to install somewhere other than the default, such as in a directory under your home directory, like "/home/fred/perl" go

   perl Build.PL --install_base /home/fred/perl

as the first step instead.

This will install the files underneath /home/fred/perl.

You will then need to make sure that you alter the PERL5LIB variable to find the modules, and the PATH variable to find the script.

Therefore you will need to change: your path, to include /home/fred/perl/script (where the script will be)

        PATH=/home/fred/perl/script:${PATH}

the PERL5LIB variable to add /home/fred/perl/lib

        PERL5LIB=/home/fred/perl/lib:${PERL5LIB}

Note that the system links dictionary will be installed as "/home/fred/perl/share/txt2html/txt2html.dict"

If you want to install in a temporary install directory (such as if you are building a package) then instead of going

   perl Build install

go

   perl Build install destdir=/my/temp/dir

and it will be installed there, with a directory structure under /my/temp/dir the same as it would be if it were installed plain. Note that this is NOT the same as setting --install_base, because certain things are done at build-time which use the install_base info.

See "perldoc perlrun" for more information on PERL5LIB, and see "perldoc Module::Build" for more information on installation options.

BUGS
Please, send to https://github.com/resurrecting-open-source-projects/txt2html/issues

SEE ALSO
perl txt2html.

AUTHOR
    Kathryn Andersen (RUBYKAT)
    perlkat AT katspace dot com
    http//www.katspace.com/

based on txt2html by Seth Golub

COPYRIGHT AND LICENCE
Original txt2html script copyright (c) 1994-2000 Seth Golub <seth AT aigeek.com>

Copyright (c) 2002-2005 by Kathryn Andersen <perlkat AT katspace dot com>

Copyright (c) 2018-2019 Joao Eriberto Mota Filho <eriberto@eriberto.pro.br> Copyright (c) 2019 Bruce Momjian <bruce@momjian.us>

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