phpman > perldoc > Text::Autoformat(3pm)

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NAME
    Text::Autoformat - Automatic text wrapping and reformatting

VERSION
    This document describes version 1.72 of Text::Autoformat

SYNOPSIS
     # Minimal use: read from STDIN, format to STDOUT...

        use Text::Autoformat;
        autoformat;

     # In-memory formatting...

        $formatted = autoformat $rawtext;

     # Configuration...

        $formatted = autoformat $rawtext, { %options };

     # Margins (1..72 by default)...

        $formatted = autoformat $rawtext, { left=>8, right=>70 };

     # Justification (left by default)...

        $formatted = autoformat $rawtext, { justify => 'left' };
        $formatted = autoformat $rawtext, { justify => 'right' };
        $formatted = autoformat $rawtext, { justify => 'full' };
        $formatted = autoformat $rawtext, { justify => 'centre' };

     # Filling (does so by default)...

        $formatted = autoformat $rawtext, { fill=>0 };

     # Squeezing whitespace (does so by default)...

        $formatted = autoformat $rawtext, { squeeze=>0 };

     # Select appropriate tabspacing (default is 8 spaces per tab):

        $formatted = autoformat $rawtext, { tabspace=>4 };

     # Case conversions...

        $formatted = autoformat $rawtext, { case => 'lower' };
        $formatted = autoformat $rawtext, { case => 'upper' };
        $formatted = autoformat $rawtext, { case => 'sentence' };
        $formatted = autoformat $rawtext, { case => 'title' };
        $formatted = autoformat $rawtext, { case => 'highlight' };
        $formatted = autoformat $rawtext, { case => \&my_case_func };

     # Selective reformatting

        $formatted = autoformat $rawtext, { ignore=>qr/^\t/ };

BACKGROUND
  The problem
    Perl plaintext formatters just aren't smart enough. Given a typical piece of plaintext in need
    of formatting:

            In comp.lang.perl.misc you wrote:
            : > <CN = Clooless Noobie> writes:
            : > CN> PERL sux because:
            : > CN>    * It doesn't have a switch statement and you have to put $
            : > CN>signs in front of everything
            : > CN>    * There are too many OR operators: having |, || and 'or'
            : > CN>operators is confusing
            : > CN>    * VB rools, yeah!!!!!!!!!
            : > CN> So anyway, how can I stop reloads on a web page?
            : > CN> Email replies only, thanks - I don't read this newsgroup.
            : >
            : > Begone, sirrah! You are a pathetic, Bill-loving, microcephalic
            : > script-infant.
            : Sheesh, what's with this group - ask a question, get toasted! And how
            : *dare* you accuse me of Ianuphilia!

    both the venerable Unix fmt tool and Perl's standard Text::Wrap module produce:

            In comp.lang.perl.misc you wrote:  : > <CN = Clooless Noobie>
            writes:  : > CN> PERL sux because:  : > CN>    * It doesn't
            have a switch statement and you have to put $ : > CN>signs in
            front of everything : > CN>    * There are too many OR
            operators: having |, || and 'or' : > CN>operators is confusing
            : > CN>    * VB rools, yeah!!!!!!!!!  : > CN> So anyway, how
            can I stop reloads on a web page?  : > CN> Email replies only,
            thanks - I don't read this newsgroup.  : > : > Begone, sirrah!
            You are a pathetic, Bill-loving, microcephalic : >
            script-infant.  : Sheesh, what's with this group - ask a
            question, get toasted! And how : *dare* you accuse me of
            Ianuphilia!

    Other formatting modules -- such as Text::Correct and Text::Format -- provide more control over
    their output, but produce equally poor results when applied to arbitrary input. They simply
    don't understand the structural conventions of the text they're reformatting.

  The solution
    The Text::Autoformat module provides a subroutine named "autoformat" that wraps text to
    specified margins. However, "autoformat" reformats its input by analysing the text's structure,
    so it wraps the above example like so:

            In comp.lang.perl.misc you wrote:
            : > <CN = Clooless Noobie> writes:
            : > CN> PERL sux because:
            : > CN>    * It doesn't have a switch statement and you
            : > CN>      have to put $ signs in front of everything
            : > CN>    * There are too many OR operators: having |, ||
            : > CN>      and 'or' operators is confusing
            : > CN>    * VB rools, yeah!!!!!!!!! So anyway, how can I
            : > CN>      stop reloads on a web page? Email replies
            : > CN>      only, thanks - I don't read this newsgroup.
            : >
            : > Begone, sirrah! You are a pathetic, Bill-loving,
            : > microcephalic script-infant.
            : Sheesh, what's with this group - ask a question, get toasted!
            : And how *dare* you accuse me of Ianuphilia!

    Note that the various quoting conventions have been observed. In fact, their structure has been
    used to determine where some paragraphs begin. Furthermore "autoformat" correctly distinguished
    between the leading '*' bullets of the nested list (which were outdented) and the leading
    emphatic '*' of "*dare*" (which was inlined).

DESCRIPTION
  Paragraphs
    The fundamental task of the "autoformat" subroutine is to identify and rearrange independent
    paragraphs in a text. Paragraphs typically consist of a series of lines containing at least one
    non-whitespace character, followed by one or more lines containing only optional whitespace.
    This is a more liberal definition than many other formatters use: most require an empty line to
    terminate a paragraph. Paragraphs may also be denoted by bulleting, numbering, or quoting (see
    the following sections).

    Once a paragraph has been isolated, "autoformat" fills and re-wraps its lines according to the
    margins that are specified in its argument list. These are placed after the text to be
    formatted, in a hash reference:

            $tidied = autoformat($messy, {left=>20, right=>60});

    By default, "autoformat" uses a left margin of 1 (first column) and a right margin of 72.

    You can also control whether (and how) "autoformat" breaks words at the end of a line, using the
    'break' option:

        # Turn off all hyphenation
        use Text::Autoformat qw(autoformat break_wrap);
            $tidied = autoformat($messy, {break=>break_wrap});

        # Default hyphenation
        use Text::Autoformat qw(autoformat break_at);
            $tidied = autoformat($messy, {break=>break_at('-')});

        # Use TeX::Hyphen module's hyphenation (module must be installed)
        use Text::Autoformat qw(autoformat break_TeX);
            $tidied = autoformat($messy, {break=>break_TeX});

    Normally, "autoformat" only reformats the first paragraph it encounters, and leaves the
    remainder of the text unaltered. This behaviour is useful because it allows a one-liner invoking
    the subroutine to be mapped onto a convenient keystroke in a text editor, to provide
    one-paragraph-at-a-time reformatting:

            % cat .exrc

            map f !Gperl -MText::Autoformat -e'autoformat'

    (Note that to facilitate such one-liners, if "autoformat" is called in a void context without
    any text data, it takes its text from "STDIN" and writes its result to "STDOUT").

    To enable "autoformat" to rearrange the entire input text at once, the "all" argument is used:

            $tidied_all = autoformat($messy, {left=>20, right=>60, all=>1});

    "autoformat" can also be directed to selectively reformat paragraphs, using the "ignore"
    argument:

            $tidied_some = autoformat($messy, {ignore=>qr/^[ \t]/});

    The value for "ignore" may be a "qr"'d regex, a subroutine reference, or the special string
    'indented'.

    If a regex is specified, any paragraph whose original text matches that regex will not be
    reformatted (i.e. it will be printed verbatim).

    If a subroutine is specified, that subroutine will be called once for each paragraph (with $_
    set to the paragraph's text). The subroutine is expected to return a true or false value. If it
    returns true, the paragraph will not be reformatted.

    If the value of the "ignore" option is the string 'indented', "autoformat" will ignore any
    paragraph in which *every* line begins with a whitespace.

    You may also specify multiple "ignore" options by including them in an array-ref:

            $tidied_mesg = autoformat($messy, {ignore=>[qr/1/,'indented']});

    One other special case of ignorance is ignoring mail headers and signature. This option is
    specified using the "mail" argument:

            $tidied_mesg = autoformat($messy_mesg, {mail=>1});

    Note that the "ignore" or "mail" options automatically imply "all".

  Bulleting and (re-)numbering
    Often plaintext will include lists that are either:

            * bulleted,
            * simply numbered (i.e. 1., 2., 3., etc.), or
            * hierarchically numbered (1, 1.1, 1.2, 1.3, 2, 2.1. and so forth).

    In such lists, each bulleted item is implicitly a separate paragraph, and is formatted
    individually, with the appropriate indentation:

            * bulleted,
            * simply numbered (i.e. 1., 2., 3.,
              etc.), or
            * hierarchically numbered (1, 1.1,
              1.2, 1.3, 2, 2.1. and so forth).

    More importantly, if the points are numbered, the numbering is checked and reordered. For
    example, a list whose points have been rearranged:

            1. Analyze problem
            3. Design algorithm
            1. Code solution
            5. Test
            4. Ship

    would be renumbered automatically by "autoformat":

            1. Analyze problem
            2. Design algorithm
            3. Code solution
            4. Test
            5. Ship

    The same reordering would be performed if the "numbering" was by letters ("a." "b." "c." etc.)
    or Roman numerals ("i." "ii." "iii.)" or by some combination of these ("1a." "1b." "2a." "2b."
    etc.) Handling disordered lists of letters and Roman numerals presents an interesting challenge.
    A list such as:

            A. Put cat in box.
            D. Close lid.
            E. Activate Geiger counter.

    should be reordered as "A." "B." "C.," whereas:

            I. Put cat in box.
            D. Close lid.
            XLI. Activate Geiger counter.

    should be reordered "I." "II." "III."

    The "autoformat" subroutine solves this problem by always interpreting alphabetic bullets as
    being letters, unless the full list consists only of valid Roman numerals, at least one of which
    is two or more characters long.

    Note that renumbering starts at the first number actually given, rather than restarting at the
    first possible number. To renumber from 1 (or A.) you must change the first numbered bullet to
    that.

    If automatic renumbering isn't wanted, just specify the 'renumber' option with a false value.

    Note that normal numbers above 1000 at the start of a line are no longer considered to be
    paragraph numbering. Numbered paragraphs running that high are exceptionally rare, and much
    rarer than paragraphs that look like these:

            Although it has long been popular (especially in the year
            2001) to point out that we now live in the Future, many
            of the promised miracles of Future Life have failed to
            eventuate. This is a new phenomenon (it didn't happen in
            1001) because the idea that the future might be different
            is a new phenomenon.

    which the former numbering rules caused to be formatted like this:

            Although it has long been popular (especially in the year

            2001) to point out that we now live in the Future, many of the
                  promised miracles of Future Life have failed to eventuate.
                  This is a new phenomenon (it didn't happen in

            2002) because the idea that the future might be different is a
                  new phenomenon.

    but which are now formatted:

            Although it has long been popular (especially in the year 2001)
            to point out that we now live in the Future, many of the
            promised miracles of Future Life have failed to eventuate. This
            is a new phenomenon (it didn't happen in 1001) because the idea
            that the future might be different is a new phenomenon.

    If you want numbers less than 1000 (or other characters strings currently treated as bullets) to
    be ignored in this way, you can turn of list formatting entirely by setting the 'lists' option
    to a false value.

    You can also select which kinds of lists are recognized, by using a string as the value of
    lists:

        # Don't recognize Roman numerals or alphabetics as list markers...
        autoformat { lists => 'number, bullet' }, $text;

        # Don't recognize bullets or numbers as list markers...
        autoformat { lists => 'roman, alpha' }, $text;

        # Recognize everything except Roman numerals as list markers...
        autoformat { lists => 'number, bullet, alpha' }, $text;

    The string should contain one or more of the following words: "number", "bullet", "alpha",
    "roman". "autoformat()" will ignore any list type that doesn't appear in the 'lists' string.

  Quoting
    Another case in which contiguous lines may be interpreted as belonging to different paragraphs,
    is where they are quoted with distinct quoters. For example:

            : > CN> So anyway, how can I stop reloads on a web page? Email
            : > CN> replies only, thanks - I don't read this newsgroup.
            : > Begone, sirrah! You are a pathetic, Bill-loving,
            : > microcephalic script-infant.
            : Sheesh, what's with this group - ask a question, get toasted!
            : And how *dare* you accuse me of Ianuphilia!

    "autoformat" recognizes the various quoting conventions used in this example and treats it as
    three paragraphs to be independently reformatted.

    You may also override the default set of recognized quoters by specifying a 'quoter' argument
    when calling "autoformat()". For example, to format lines such as:

            // This is a comment
            // in the standard C(++)
            // comment-to-EOL
            // format

    specify:

        autoformat($text, { quoter =E<gt> qr{//} })

    Instead of completely replacing the existing set of quoters, you can *extend* them by specifying
    a pattern that includes the metasequence "<QUOTER>", which is then replaced by the module's
    standard pattern for quoters. So, for example, to add "//" to the set of existing quoters:

        autoformat($text, { quoter =E<gt> qr{//|<QUOTER>} })

    Block quotations present a different challenge. A typical formatter would render the following
    quotation:

            "We are all of us in the gutter, but some of us are looking at
             the stars"
                                    -- Oscar Wilde

    like so:

            "We are all of us in the gutter, but some of us are looking at
            the stars" -- Oscar Wilde

    "autoformat" recognizes the quotation structure by matching the following regular expression
    against the text component of each paragraph:

            / \A(\s*) # leading whitespace for quotation (["']|``) # opening
            quotemark (.*) # quotation (''|\2) # closing quotemark \s*?\n #
            trailing whitespace after quotation (\1[ ]+) # leading
            whitespace for attribution
                                    #   (must be indented more than
                                    #   quotation)
              (--|-) # attribution introducer ([^\n]*?\n) # first
              attribution line ((\5[^\n]*?$)*) # other attribution lines
                                    #   (indented no less than first line)
              \s*\Z # optional whitespace to end of paragraph /xsm

    When reformatted (see below), the indentation and the attribution structure will be preserved:

            "We are all of us in the gutter, but some of us are looking
             at the stars"
                                    -- Oscar Wilde

  Widow control
    Note that in the last example, "autoformat" broke the line at column 68, four characters earlier
    than it should have. It did so because, if the full margin width had been used, the formatting
    would have left the last two words by themselves on an oddly short last line:

            "We are all of us in the gutter, but some of us are looking at
            the stars"

    This phenomenon is known as "widowing" and is heavily frowned upon in typesetting circles. It
    looks ugly in plaintext too, so "autoformat" avoids it by stealing extra words from earlier
    lines in a paragraph, so as to leave enough for a reasonable last line. The heuristic used is
    that final lines must be at least 10 characters long (though this number may be adjusted by
    passing a "widow => *minlength*" argument to "autoformat").

    If the last line is too short, the paragraph's right margin is reduced by one column, and the
    paragraph is reformatted. This process iterates until either the last line exceeds nine
    characters or the margins have been narrowed by 10% of their original separation. In the latter
    case, the reformatter gives up and uses its original formatting.

  Justification
    The "autoformat" subroutine also takes a named argument: "{justify => *type*}", which specifies
    how each paragraph is to be justified. The options are: 'left' (the default), "'right',"
    'centre' (or 'center'), and 'full'. These act on the complete paragraph text (but *not* on any
    quoters before that text). For example, with 'right' justification:

            R3>     Now is the Winter of our discontent made
            R3> glorious Summer by this son of York. And all
            R3> the clouds that lour'd upon our house In the
            R3>              deep bosom of the ocean buried.

    Full justification is interesting in a fixed-width medium like plaintext because it usually
    results in uneven spacing between words. Typically, formatters provide this by distributing the
    extra spaces into the first available gaps of each line:

            R3> Now  is  the  Winter  of our discontent made
            R3> glorious Summer by this son of York. And all
            R3> the  clouds  that  lour'd  upon our house In
            R3> the deep bosom of the ocean buried.

    This produces a rather jarring visual effect, so "autoformat" reverses the strategy and inserts
    extra spaces at the end of lines:

            R3> Now is the  Winter of  our  discontent  made
            R3> glorious Summer by this son of York. And all
            R3> the clouds that lour'd  upon  our  house  In
            R3> the deep bosom of the ocean buried.

    Most readers find this less disconcerting.

  Implicit centring
    Even if explicit centring is not specified, "autoformat" will attempt to automatically detect
    centred paragraphs and preserve their justification. It does this by examining each line of the
    paragraph and asking: "if this line were part of a centred paragraph, where would the centre
    line have been?"

    The answer can be determined by adding the length of leading whitespace before the first word,
    plus half the length of the full set of words on the line. That is, for a single line:

            $line =~ /^(\s*)(.*?)(\s*)$/ $centre =
            length($1)+0.5*length($2);

    By making the same estimate for every line, and then comparing the estimates, it is possible to
    deduce whether all the lines are centred with respect to the same axis of symmetry (with an
    allowance of ?1 to cater for the inevitable rounding when the centre positions of even-length
    rows were originally computed). If a common axis of symmetry is detected, "autoformat" assumes
    that the lines are supposed to be centred, and switches to centre-justification mode for that
    paragraph.

    Note that this behaviour can to switched off entirely by setting the "autocentre" argument
    false.

  Case transformations
    The "autoformat" subroutine can also optionally perform case conversions on the text it
    processes. The "{case => *type*}" argument allows the user to specify six different conversions:

    'upper'
        This mode unconditionally converts every letter in the reformatted text to upper-case;

    'lower'
        This mode unconditionally converts every letter in the reformatted text to lower-case;

    'sentence'
        This mode attempts to generate correctly-cased sentences from the input text. That is, the
        first letter after a sentence-terminating punctuator is converted to upper-case. Then, each
        subsequent word in the sentence is converted to lower-case, unless that word is originally
        mixed-case or contains punctuation. For example, under "{case => 'sentence'}":

                'POVERTY, MISERY, ETC. are the lot of the PhD candidate. alas!'

        becomes:

                'Poverty, misery, etc. are the lot of the PhD candidate. Alas!'

        Note that "autoformat" is clever enough to recognize that the period after abbreviations
        such as "etc." is not a sentence terminator.

        If the argument is specified as 'sentence ' (with one or more trailing whitespace
        characters) those characters are used to replace the single space that appears at the end of
        the sentence. For example, "autoformat($text, {case=>'sentence '}") would produce:

                'Poverty, misery, etc. are the lot of the PhD candidate. Alas!'

    'title'
        This mode behaves like 'sentence' except that the first letter of *every* word is
        capitalized:

                'What I Did On My Summer Vacation In Monterey'

    'highlight'
        This mode behaves like 'title' except that trivial words are not capitalized:

                'What I Did on my Summer Vacation in Monterey'

    "sub{...}"
        If the argument for 'case' is a subroutine reference, that subroutine is applied to each
        word and the result replaces the word in the text.

        For example, to convert a string to hostage-case:

            my $ransom_note = sub {
                return join "",                    # ^  Reconcatenate
                       map {/[aeiou]/i ? lc : uc}  # |  uPPeR aND LoWeR each
                       split //,                   # |  Break into chars
                       shift;                      # |  Take argument
            };

            $text = autoformat($text, {case => $ransom_note });
            # "FoR eXaMPLe, To CoNVeRT a STRiNG To HoSTaGe-CaSe:"

        Or to highlight particular words:

            my @SPECIAL = qw( perl camel wall );
            sub highlight_specials {
                my ($word) = @_;
                return $word ~~ @SPECIAL ? uc($word) : $word;
            }

            $text = autoformat($text, {case => \&highlight_specials});
            # "It is easier for a CAMEL to pass through a WALL of PERL..."

  Selective reformatting
    You can select which paragraphs "autoformat" actually reformats (or, rather, those it *doesn't*
    reformat) using the "ignore" flag.

    For example:

            # Reformat all paras except those containing "verbatim"...
            print autoformat { all => 1, ignore => qr/verbatim/i }, $text;

            # Reformat all paras except those less that 3 lines long...
            print autoformat { all => 1, ignore => sub { tr/\n/\n/ < 3
            } }, $text;

            # Reformat all paras except those that are indented...
            print autoformat { all => 1, ignore => qr/^\s/m }, $text;

            # Reformat all paras except those that are indented (easier)...
            print autoformat { all => 1, ignore => 'indented' }, $text;

  Handling tabs
    Text::Autoformat replaces any tabs in the text it's formatting with the appropriate number of
    spaces (using Text::Tabs to do its dirty work). It normally assumes that each tab is equivalent
    to 8 space characters, but you can change that default using the 'tabspace' option:

            print autoformat { tabspace => 4 }, $text;

SEE ALSO
    Text::Reform - provides functions for manual text wrapping and reformatting.

    Text::Aligner - provides a single function for justifying strings according to various styles.

    Text::Format - a class that provides methods for formatting text in various ways.

    Data::Formatter::Text - format various Perl data structures as text, in different ways according
    to the type of data.

REPOSITORY
    <https://github.com/neilb/Text-Autoformat>

AUTHOR
    Damian Conway (damian AT conway.org)

BUGS
    There are undoubtedly serious bugs lurking somewhere in code this funky :-) Bug reports and
    other feedback are most welcome.

LICENCE AND COPYRIGHT
    Copyright (c) 1997-2007, Damian Conway "<DCONWAY AT CPAN.org>". All rights reserved.

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

DISCLAIMER OF WARRANTY
    BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE
    EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
    HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
    EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
    AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE
    SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY
    SERVICING, REPAIR, OR CORRECTION.

    IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER,
    OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE
    LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR
    CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT
    LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
    PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR
    OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

Text::Autoformat(3pm)
NAME VERSION SYNOPSIS BACKGROUND
The problem The solution
DESCRIPTION
Paragraphs Quoting Widow control Justification Implicit centring Case transformations Selective reformatting Handling tabs
SEE ALSO REPOSITORY AUTHOR BUGS LICENCE AND COPYRIGHT DISCLAIMER OF WARRANTY

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