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NAME VERSION SYNOPSIS DESCRIPTION AUTHOR BUGS LICENCE AND COPYRIGHT DISCLAIMER OF WARRANTY
NAME
    Text::Reform - Manual text wrapping and reformatting

VERSION
    This document describes version 1.20 of Text::Reform, released
    2009-09-06.

SYNOPSIS
            use Text::Reform;

            print form $template,
                       $data, $to, $fill, $it, $with;


            use Text::Reform qw( tag );

            print tag 'B', $enboldened_text;

DESCRIPTION
  The "form" sub
    The "form()" subroutine may be exported from the module. It takes a
    series of format (or "picture") strings followed by replacement values,
    interpolates those values into each picture string, and returns the
    result. The effect is similar to the inbuilt perl "format" mechanism,
    although the field specification syntax is simpler and some of the
    formatting behaviour is more sophisticated.

    A picture string consists of sequences of the following characters:

    <       Left-justified field indicator. A series of two or more
            sequential <'s specify a left-justified field to be filled by a
            subsequent value. A single < is formatted as the literal
            character '<'

    >       Right-justified field indicator. A series of two or more
            sequential >'s specify a right-justified field to be filled by a
            subsequent value. A single > is formatted as the literal
            character '>'

    <<<>>>  Fully-justified field indicator. Field may be of any width, and
            brackets need not balance, but there must be at least 2 '<' and
            2 '>'.

    ^       Centre-justified field indicator. A series of two or more
            sequential ^'s specify a centred field to be filled by a
            subsequent value. A single ^ is formatted as the literal
            character '^'

    >>>.<<<<
            A numerically formatted field with the specified number of
            digits to either side of the decimal place. See "Numerical
            formatting" below.

    [       Left-justified block field indicator. Just like a < field,
            except it repeats as required on subsequent lines. See below. A
            single [ is formatted as the literal character '['

    ]       Right-justified block field indicator. Just like a > field,
            except it repeats as required on subsequent lines. See below. A
            single ] is formatted as the literal character ']'

    [[[]]]  Fully-justified block field indicator. Just like a <<<>>> field,
            except it repeats as required on subsequent lines. See below.
            Field may be of any width, and brackets need not balance, but
            there must be at least 2 '[' and 2 ']'.

    |       Centre-justified block field indicator. Just like a ^ field,
            except it repeats as required on subsequent lines. See below. A
            single | is formatted as the literal character '|'

    ]]].[[[[
            A numerically formatted block field with the specified number of
            digits to either side of the decimal place. Just like a >>>.<<<<
            field, except it repeats as required on subsequent lines. See
            below.

    ~       A one-character wide block field.

    \       Literal escape of next character (e.g. "\~" is formatted as '~',
            not a one character wide block field).

    Any other character
            That literal character.

    Any substitution value which is "undef" (either explicitly so, or
    because it is missing) is replaced by an empty string.

  Controlling line filling.
    Note that, unlike the a perl "format", "form" preserves whitespace
    (including newlines) unless called with certain options.

    The "squeeze" option (when specified with a true value) causes any
    sequence of spaces and/or tabs (but not newlines) in an interpolated
    string to be replaced with a single space.

    A true value for the "fill" option causes (only) newlines to be
    squeezed.

    To minimize all whitespace, you need to specify both options. Hence:

            $format = "EG> [[[[[[[[[[[[[[[[[[[[[";
            $data   = "h  e\t l lo\nworld\t\t\t\t\t";

            print form $format, $data;              # all whitespace preserved:
                                                    #
                                                    # EG> h  e            l lo
                                                    # EG> world


            print form {squeeze=>1},                # only newlines preserved:
                       $format, $data;              #
                                                    # EG> h e l lo
                                                    # EG> world


            print form {fill=>1},                   # only spaces/tabs preserved:
                        $format, $data;             #
                                                    # EG> h  e        l lo world


            print form {squeeze=>1, fill=>1},       # no whitespace preserved:
                       $format, $data;              #
                                                    # EG> h e l lo world

    Whether or not filling or squeezing is in effect, "form" can also be
    directed to trim any extra whitespace from the end of each line it
    formats, using the "trim" option. If this option is specified with a
    true value, every line returned by "form" will automatically have the
    substitution "s/[ \t]+$//gm" applied to it.

    Hence:

            print length form "[[[[[[[[[[", "short";
            # 11

            print length form {trim=>1}, "[[[[[[[[[[", "short";
            # 6

    It is also possible to control the character used to fill lines that are
    too short, using the 'filler' option. If this option is specified the
    value of the 'filler' flag is used as the fill string, rather than the
    default " ".

    For example:

            print form { filler=>'*' },
                    "Pay bearer: ^^^^^^^^^^^^^^^^^^^",
                    '$123.45';

    prints:

            Pay bearer: ******$123.45******

    If the filler string is longer than one character, it is truncated to
    the appropriate length. So:

            print form { filler=>'-->' },
                    "Pay bearer: ]]]]]]]]]]]]]]]]]]]",
                    ['$1234.50', '$123.45', '$12.34'];

    prints:

            Pay bearer: ->-->-->-->$1234.50
            Pay bearer: -->-->-->-->$123.45
            Pay bearer: >-->-->-->-->$12.34

    If the value of the 'filler' option is a hash, then it's 'left' and
    'right' entries specify separate filler strings for each side of an
    interpolated value. So:

            print form { filler=>{left=>'->', right=>'*'} },
                    "Pay bearer: <<<<<<<<<<<<<<<<<<",
                    '$123.45',
                    "Pay bearer: >>>>>>>>>>>>>>>>>>",
                    '$123.45',
                    "Pay bearer: ^^^^^^^^^^^^^^^^^^",
                    '$123.45';

    prints:

            Pay bearer: $123.45***********
            Pay bearer: >->->->->->$123.45
            Pay bearer: >->->$123.45******

  Temporary and permanent default options
    If "form" is called with options, but no template string or data, it
    resets it's defaults to the options specified. If called in a void
    context:

            form { squeeze => 1, trim => 1 };

    the options become permanent defaults.

    However, when called with only options in non-void context, "form"
    resets its defaults to those options and returns an object. The reset
    default values persist only until that returned object is destroyed.
    Hence to temporarily reset "form"'s defaults within a single subroutine:

            sub single {
                    my $tmp = form { squeeze => 1, trim => 1 };

                    # do formatting with the obove defaults

            } # form's defaults revert to previous values as $tmp object destroyed

  Multi-line format specifiers and interleaving
    By default, if a format specifier contains two or more lines (i.e. one
    or more newline characters), the entire format specifier is repeatedly
    filled as a unit, until all block fields have consumed their
    corresponding arguments. For example, to build a simple look-up table:

            my @values   = (1..12);

            my @squares  = map { sprintf "%.6g", $_**2    } @values;
            my @roots    = map { sprintf "%.6g", sqrt($_) } @values;
            my @logs     = map { sprintf "%.6g", log($_)  } @values;
            my @inverses = map { sprintf "%.6g", 1/$_     } @values;

            print form
            "  N      N**2    sqrt(N)      log(N)      1/N",
            "=====================================================",
            "| [[  |  [[[  |  [[[[[[[[[[ | [[[[[[[[[ | [[[[[[[[[ |
            -----------------------------------------------------",
            \@values, \@squares, \@roots, \@logs, \@inverses;

    The multiline format specifier:

            "| [[  |  [[[  |  [[[[[[[[[[ | [[[[[[[[[ | [[[[[[[[[ |
            -----------------------------------------------------",

    is treated as a single logical line. So "form" alternately fills the
    first physical line (interpolating one value from each of the arrays)
    and the second physical line (which puts a line of dashes between each
    row of the table) producing:

              N      N**2    sqrt(N)      log(N)      1/N
            =====================================================
            | 1   |  1    |  1          | 0         | 1         |
            -----------------------------------------------------
            | 2   |  4    |  1.41421    | 0.693147  | 0.5       |
            -----------------------------------------------------
            | 3   |  9    |  1.73205    | 1.09861   | 0.333333  |
            -----------------------------------------------------
            | 4   |  16   |  2          | 1.38629   | 0.25      |
            -----------------------------------------------------
            | 5   |  25   |  2.23607    | 1.60944   | 0.2       |
            -----------------------------------------------------
            | 6   |  36   |  2.44949    | 1.79176   | 0.166667  |
            -----------------------------------------------------
            | 7   |  49   |  2.64575    | 1.94591   | 0.142857  |
            -----------------------------------------------------
            | 8   |  64   |  2.82843    | 2.07944   | 0.125     |
            -----------------------------------------------------
            | 9   |  81   |  3          | 2.19722   | 0.111111  |
            -----------------------------------------------------
            | 10  |  100  |  3.16228    | 2.30259   | 0.1       |
            -----------------------------------------------------
            | 11  |  121  |  3.31662    | 2.3979    | 0.0909091 |
            -----------------------------------------------------
            | 12  |  144  |  3.4641     | 2.48491   | 0.0833333 |
            -----------------------------------------------------

    This implies that formats and the variables from which they're filled
    need to be interleaved. That is, a multi-line specification like this:

            print form
            "Passed:                      ##
               [[[[[[[[[[[[[[[             # single format specification
            Failed:                        # (needs two sets of data)
               [[[[[[[[[[[[[[[",          ##

            \@passes, \@fails;            ##  data for previous format

    would print:

            Passed:
               <pass 1>
            Failed:
               <fail 1>
            Passed:
               <pass 2>
            Failed:
               <fail 2>
            Passed:
               <pass 3>
            Failed:
               <fail 3>

    because the four-line format specifier is treated as a single unit, to
    be repeatedly filled until all the data in @passes and @fails has been
    consumed.

    Unlike the table example, where this unit filling correctly put a line
    of dashes between lines of data, in this case the alternation of passes
    and fails is probably *not* the desired effect.

    Judging by the labels, it is far more likely that the user wanted:

            Passed:
               <pass 1>
               <pass 2>
               <pass 3>
            Failed:
               <fail 4>
               <fail 5>
               <fail 6>

    To achieve that, either explicitly interleave the formats and their data
    sources:

            print form
            "Passed:",               ## single format (no data required)
            "   [[[[[[[[[[[[[[[",    ## single format (needs one set of data)
                \@passes,            ## data for previous format
            "Failed:",               ## single format (no data required)
            "   [[[[[[[[[[[[[[[",    ## single format (needs one set of data)
                \@fails;             ## data for previous format

    or instruct "form" to do it for you automagically, by setting the
    'interleave' flag true:

            print form {interleave=>1}
            "Passed:                 ##
               [[[[[[[[[[[[[[[        # single format
            Failed:                   # (needs two sets of data)
               [[[[[[[[[[[[[[[",     ##

                                     ## data to be automagically interleaved
            \@passes, \@fails;        # as necessary between lines of previous
                                     ## format

  How "form" hyphenates
    Any line with a block field repeats on subsequent lines until all block
    fields on that line have consumed all their data. Non-block fields on
    these lines are replaced by the appropriate number of spaces.

    Words are wrapped whole, unless they will not fit into the field at all,
    in which case they are broken and (by default) hyphenated. Simple
    hyphenation is used (i.e. break at the *N-1*th character and insert a
    '-'), unless a suitable alternative subroutine is specified instead.

    Words will not be broken if the break would leave less than 2 characters
    on the current line. This minimum can be varied by setting the
    'minbreak' option to a numeric value indicating the minimum total broken
    characters (including hyphens) required on the current line. Note that,
    for very narrow fields, words will still be broken (but *unhyphenated*).
    For example:

            print form '~', 'split';

    would print:

            s
            p
            l
            i
            t

    whilst:

            print form {minbreak=>1}, '~', 'split';

    would print:

            s-
            p-
            l-
            i-
            t

    Alternative breaking subroutines can be specified using the "break"
    option in a configuration hash. For example:

            form { break => \&my_line_breaker }
                 $format_str,
                 @data;

    "form" expects any user-defined line-breaking subroutine to take three
    arguments (the string to be broken, the maximum permissible length of
    the initial section, and the total width of the field being filled). The
    "hypenate" sub must return a list of two strings: the initial (broken)
    section of the word, and the remainder of the string respectively).

    For example:

            sub tilde_break = sub($$$)
            {
                    (substr($_[0],0,$_[1]-1).'~', substr($_[0],$_[1]-1));
            }

            form { break => \&tilde_break }
                 $format_str,
                 @data;

    makes '~' the hyphenation character, whilst:

            sub wrap_and_slop = sub($$$)
            {
                    my ($text, $reqlen, $fldlen) = @_;
                    if ($reqlen==$fldlen) { $text =~ m/\A(\s*\S*)(.*)/s }
                    else                  { ("", $text) }
            }

            form { break => \&wrap_and_slop }
                 $format_str,
                 @data;

    wraps excessively long words to the next line and "slops" them over the
    right margin if necessary.

    The Text::Reform package provides three functions to simplify the use of
    variant hyphenation schemes. The exportable subroutine
    "Text::Reform::break_wrap" generates a reference to a subroutine
    implementing the "wrap-and-slop" algorithm shown in the last example,
    which could therefore be rewritten:

            use Text::Reform qw( form break_wrap );

            form { break => break_wrap }
                 $format_str,
                 @data;

    The subroutine "Text::Reform::break_with" takes a single string argument
    and returns a reference to a sub which hyphenates by cutting off the
    text at the right margin and appending the string argument. Hence the
    first of the two examples could be rewritten:

            use Text::Reform qw( form break_with );

            form { break => break_with('~') }
                 $format_str,
                 @data;

    The subroutine "Text::Reform::break_at" takes a single string argument
    and returns a reference to a sub which hyphenates by breaking
    immediately after that string. For example:

            use Text::Reform qw( form break_at );

            form { break => break_at('-') }
                   "[[[[[[[[[[[[[[",
                   "The Newton-Raphson methodology";

            # returns:
            #
            #       "The Newton-
            #        Raphson
            #        methodology"

    Note that this differs from the behaviour of "break_with", which would
    be:

            form { break => break_with('-') }
                   "[[[[[[[[[[[[[[",
                   "The Newton-Raphson methodology";

            # returns:
            #
            #       "The Newton-R-
            #        aphson metho-
            #        dology"

    Hence "break_at" is generally a better choice.

    "break_at" also takes an 'except' option, which tells the resulting
    subroutine not to break in the middle of certain strings. For example:

            form { break => break_at('-', {except=>qr/Newton-Raphson/}) }
                   "[[[[[[[[[[[[[[",
                   "The Newton-Raphson methodology";

            # returns:
            #
            #       "The
        #        Newton-Raphson
            #        methodology"

    This option is particularly useful for preserving URLs.

    The subroutine "Text::Reform::break_TeX" returns a reference to a sub
    which hyphenates using Jan Pazdziora's TeX::Hyphen module. For example:

            use Text::Reform qw( form break_wrap );

            form { break => break_TeX }
                 $format_str,
                 @data;

    Note that in the previous examples there is no leading '\&' before
    "break_wrap", "break_with", or "break_TeX", since each is being directly
    *called* (and returns a reference to some other suitable subroutine);

  The "form" formatting algorithm
    The algorithm "form" uses is:

            1. If interleaving is specified, split the first string in the
               argument list into individual format lines and add a
               terminating newline (unless one is already present).
               Otherwise, treat the entire string as a single "line" (like
               /s does in regexes)

            2. For each format line...

                    2.1. determine the number of fields and shift
                         that many values off the argument list and
                         into the filling list. If insufficient
                         arguments are available, generate as many
                         empty strings as are required.

                    2.2. generate a text line by filling each field
                         in the format line with the initial contents
                         of the corresponding arg in the filling list
                         (and remove those initial contents from the arg).

                    2.3. replace any <,>, or ^ fields by an equivalent
                         number of spaces. Splice out the corresponding
                         args from the filling list.

                    2.4. Repeat from step 2.2 until all args in the
                         filling list are empty.

            3. concatenate the text lines generated in step 2

            4. repeat from step 1 until the argument list is empty

  "form" examples
    As an example of the use of "form", the following:

            $count = 1;
            $text = "A big long piece of text to be formatted exquisitely";

            print form q
            q{       ||||  <<<<<<<<<<   },
            $count, $text,
            q{       ----------------   },
            q{       ^^^^  ]]]]]]]]]]|  },
            $count+11, $text,
            q{                       =
                     ]]].[[[            },
            "123 123.4\n123.456789";

    produces the following output:

                     1    A big long
                    ----------------
                     12     piece of|
                          text to be|
                           formatted|
                          exquisite-|
                                  ly|
                                    =
                    123.0
                                    =
                    123.4
                                    =
                    123.456

    Note that block fields in a multi-line format string, cause the entire
    multi-line format to be repeated as often as necessary.

    Picture strings and replacement values are interleaved in the
    traditional "format" format, but care is needed to ensure that the
    correct number of substitution values are provided. Another example:

            $report = form
                    'Name           Rank    Serial Number',
                    '====           ====    =============',
                    '<<<<<<<<<<<<<  ^^^^    <<<<<<<<<<<<<',
                     $name,         $rank,  $serial_number,
                    ''
                    'Age    Sex     Description',
                    '===    ===     ===========',
                    '^^^    ^^^     [[[[[[[[[[[',
                     $age,  $sex,   $description;

  How "form" consumes strings
    Unlike "format", within "form" non-block fields *do* consume the text
    they format, so the following:

            $text = "a line of text to be formatted over three lines";
            print form "<<<<<<<<<<\n  <<<<<<<<\n    <<<<<<\n",
                        $text,        $text,        $text;

    produces:

            a line of
              text to
                be fo-

    not:

            a line of
              a line
                a line

    To achieve the latter effect, convert the variable arguments to
    independent literals (by double-quoted interpolation):

            $text = "a line of text to be formatted over three lines";
            print form "<<<<<<<<<<\n  <<<<<<<<\n    <<<<<<\n",
                       "$text",      "$text",      "$text";

    Although values passed from variable arguments are progressively
    consumed *within* "form", the values of the original variables passed to
    "form" are *not* altered. Hence:

            $text = "a line of text to be formatted over three lines";
            print form "<<<<<<<<<<\n  <<<<<<<<\n    <<<<<<\n",
                        $text,        $text,        $text;
            print $text, "\n";

    will print:

            a line of
              text to
                be fo-
            a line of text to be formatted over three lines

    To cause "form" to consume the values of the original variables passed
    to it, pass them as references. Thus:

            $text = "a line of text to be formatted over three lines";
            print form "<<<<<<<<<<\n  <<<<<<<<\n    <<<<<<\n",
                        \$text,       \$text,       \$text;
            print $text, "\n";

    will print:

            a line of
              text to
                be fo-
            rmatted over three lines

    Note that, for safety, the "non-consuming" behaviour takes precedence,
    so if a variable is passed to "form" both by reference *and* by value,
    its final value will be unchanged.

  Numerical formatting
    The ">>>.<<<" and "]]].[[[" field specifiers may be used to format
    numeric values about a fixed decimal place marker. For example:

            print form '(]]]]].[[)', <<EONUMS;
                       1
                       1.0
                       1.001
                       1.009
                       123.456
                       1234567
                       one two
            EONUMS

    would print:

            (    1.0 )
            (    1.0 )
            (    1.00)
            (    1.01)
            (  123.46)
            (#####.##)
            (?????.??)
            (?????.??)

    Fractions are rounded to the specified number of places after the
    decimal, but only significant digits are shown. That's why, in the above
    example, 1 and 1.0 are formatted as "1.0", whilst 1.001 is formatted as
    "1.00".

    You can specify that the maximal number of decimal places always be used
    by giving the configuration option 'numeric' a value that matches
    /\bAllPlaces\b/i. For example:

            print form { numeric => AllPlaces },
                       '(]]]]].[[)', <<'EONUMS';
                       1
                       1.0
            EONUMS

    would print:

            (    1.00)
            (    1.00)

    Note that although decimal digits are rounded to fit the specified
    width, the integral part of a number is never modified. If there are not
    enough places before the decimal place to represent the number, the
    entire number is replaced with hashes.

    If a non-numeric sequence is passed as data for a numeric field, it is
    formatted as a series of question marks. This querulous behaviour can be
    changed by giving the configuration option 'numeric' a value that
    matches /\bSkipNaN\b/i in which case, any invalid numeric data is simply
    ignored. For example:

            print form { numeric => 'SkipNaN' }
                       '(]]]]].[[)',
                       <<EONUMS;
                       1
                       two three
                       4
            EONUMS

    would print:

            (    1.0 )
            (    4.0 )

  Filling block fields with lists of values
    If an argument corresponding to a field is an array reference, then
    "form" automatically joins the elements of the array into a single
    string, separating each element with a newline character. As a result, a
    call like this:

            @values = qw( 1 10 100 1000 );
            print form "(]]]].[[)", \@values;

    will print out

             (   1.00)
             (  10.00)
             ( 100.00)
             (1000.00)

    as might be expected.

    Note however that arrays must be passed by reference (so that "form"
    knows that the entire array holds data for a single field). If the
    previous example had not passed @values by reference:

            @values = qw( 1 10 100 1000 );
            print form "(]]]].[[)", @values;

    the output would have been:

             (   1.00)
             10
             100
             1000

    This is because @values would have been interpolated into "form"'s
    argument list, so only $value[0] would have been used as the data for
    the initial format string. The remaining elements of @value would have
    been treated as separate format strings, and printed out "verbatim".

    Note too that, because arrays must be passed using a reference, their
    original contents are consumed by "form", just like the contents of
    scalars passed by reference.

    To avoid having an array consumed by "form", pass it as an anonymous
    array:

            print form "(]]]].[[)", [@values];

  Headers, footers, and pages
    The "form" subroutine can also insert headers, footers, and page-feeds
    as it formats. These features are controlled by the "header", "footer",
    "pagefeed", "pagelen", and "pagenum" options.

    The "pagenum" option takes a scalar value or a reference to a scalar
    variable and starts page numbering at that value. If a reference to a
    scalar variable is specified, the value of that variable is updated as
    the formatting proceeds, so that the final page number is available in
    it after formatting. This can be useful for multi-part reports.

    The "pagelen" option specifies the total number of lines in a page
    (including headers, footers, and page-feeds).

    The "pagewidth" option specifies the total number of columns in a page.

    If the "header" option is specified with a string value, that string is
    used as the header of every page generated. If it is specified as a
    reference to a subroutine, that subroutine is called at the start of
    every page and its return value used as the header string. When called,
    the subroutine is passed the current page number.

    Likewise, if the "footer" option is specified with a string value, that
    string is used as the footer of every page generated. If it is specified
    as a reference to a subroutine, that subroutine is called at the *start*
    of every page and its return value used as the footer string. When
    called, the footer subroutine is passed the current page number.

    Both the header and footer options can also be specified as hash
    references. In this case the hash entries for keys "left", "centre" (or
    "center"), and "right" specify what is to appear on the left, centre,
    and right of the header/footer. The entry for the key "width" specifies
    how wide the footer is to be. If the "width" key is omitted, the
    "pagewidth" configuration option (which defaults to 72 characters) is
    used.

    The "left", "centre", and "right" values may be literal strings, or
    subroutines (just as a normal header/footer specification may be.) See
    the second example, below.

    Another alternative for header and footer options is to specify them as
    a subroutine that returns a hash reference. The subroutine is called for
    each page, then the resulting hash is treated like the hashes described
    in the preceding paragraph. See the third example, below.

    The "pagefeed" option acts in exactly the same way, to produce a
    pagefeed which is appended after the footer. But note that the pagefeed
    is not counted as part of the page length.

    All three of these page components are recomputed at the start of each
    new page, before the page contents are formatted (recomputing the header
    and footer first makes it possible to determine how many lines of data
    to format so as to adhere to the specified page length).

    When the call to "form" is complete and the data has been fully
    formatted, the footer subroutine is called one last time, with an extra
    argument of 1. The string returned by this final call is used as the
    final footer.

    So for example, a 60-line per page report, starting at page 7, with
    appropriate headers and footers might be set up like so:

            $page = 7;

            form { header => sub { "Page $_[0]\n\n" },
                   footer => sub { my ($pagenum, $lastpage) = @_;
                                   return "" if $lastpage;
                                   return "-"x50 . "\n"
                                                 .form ">"x50, "...".($pagenum+1);
                                  },
                   pagefeed => "\n\n",
                   pagelen  => 60
                   pagenum => \$page,
                 },
                 $template,
                 @data;

    Note the recursive use of "form" within the "footer" option!

    Alternatively, to set up headers and footers such that the running head
    is right justified in the header and the page number is centred in the
    footer:

            form { header => { right => "Running head" },
                   footer => { centre => sub { "Page $_[0]" } },
                   pagelen  => 60
                 },
                 $template,
                 @data;

    The footer in the previous example could also have been specified the
    other way around, as a subroutine that returns a hash (rather than a
    hash containing a subroutine):

            form { header => { right => "Running head" },
                   footer => sub { return {centre => "Page $_[0]"} },
                   pagelen  => 60
                 },
                 $template,
                 @data;

  The "cols" option
    Sometimes data to be used in a "form" call needs to be extracted from a
    nested data structure. For example, whilst it's easy to print a table if
    you already have the data in columns:

            @name  = qw(Tom Dick Harry);
            @score = qw( 88   54    99);
            @time  = qw( 15   13    18);

            print form
            '-------------------------------',
            'Name             Score     Time',
            '-------------------------------',
            '[[[[[[[[[[[[[[   |||||     ||||',
             \@name,          \@score,  \@time;

    if the data is aggregrated by rows:

            @data = (
                { name=>'Tom',   score=>88, time=>15 },
                { name=>'Dick',  score=>54, time=>13 },
                { name=>'Harry', score=>99, time=>18 },
            );

    you need to do some fancy mapping before it can be fed to "form":

            print form
            '-------------------------------',
            'Name             Score     Time',
            '-------------------------------',
            '[[[[[[[[[[[[[[   |||||     ||||',
            [map $$_{name},  @data],
            [map $$_{score}, @data],
            [map $$_{time} , @data];

    Or you could just use the 'cols' option:

            use Text::Reform qw(form columns);

            print form
            '-------------------------------',
            'Name             Score     Time',
            '-------------------------------',
            '[[[[[[[[[[[[[[   |||||     ||||',
            { cols => [qw(name score time)],
              from => \@data
            };

    This option takes an array of strings that specifies the keys of the
    hash entries to be extracted into columns. The 'from' entry (which must
    be present) also takes an array, which is expected to contain a list of
    references to hashes. For each key specified, this option inserts into
    "form"'s argument list a reference to an array containing the entries
    for that key, extracted from each of the hash references supplied by
    'from'. So, for example, the option:

            { cols => [qw(name score time)],
              from => \@data
            }

    is replaced by three array references, the first containing the 'name'
    entries for each hash inside @data, the second containing the 'score'
    entries for each hash inside @data, and the third containing the 'time'
    entries for each hash inside @data.

    If, instead, you have a list of arrays containing the data:

            @data = (
                    # Time  Name     Score
                    [ 15,   'Tom',   88 ],
                    [ 13,   'Dick',  54 ],
                    [ 18,   'Harry', 99 ],
            );

    the 'cols' option can extract the appropriate columns for that too. You
    just specify the required indices, rather than keys:

            print form
            '-----------------------------',
            'Name             Score   Time',
            '-----------------------------',
            '[[[[[[[[[[[[[[   |||||   ||||',
            { cols => [1,2,0],
              from => \@data
            }

    Note that the indices can be in any order, and the resulting arrays are
    returned in the same order.

    If you need to merge columns extracted from two hierarchical data
    structures, just concatenate the data structures first, like so:

            print form
            '---------------------------------------',
            'Name             Score   Time   Ranking
            '---------------------------------------',
            '[[[[[[[[[[[[[[   |||||   ||||   |||||||',
            { cols => [1,2,0],
              from => [@data, @olddata],
            }

    Of course, this only works if the columns are in the same positions in
    both data sets (and both datasets are stored in arrays) or if the
    columns have the same keys (and both datasets are in hashes). If not,
    you would need to format each dataset separately, like so:

            print form
            '-----------------------------',
            'Name             Score   Time'
            '-----------------------------',
            '[[[[[[[[[[[[[[   |||||   ||||',
            { cols=>[1,2,0],  from=>\@data },
            '[[[[[[[[[[[[[[   |||||   ||||',
            { cols=>[3,8,1],  from=>\@olddata },
            '[[[[[[[[[[[[[[   |||||   ||||',
            { cols=>[qw(name score time)],  from=>\@otherdata };

  The "tag" sub
    The "tag" subroutine may be exported from the module. It takes two
    arguments: a tag specifier and a text to be entagged. The tag specifier
    indicates the indenting of the tag, and of the text. The sub generates
    an end-tag (using the usual "/*tag*" variant), unless an explicit
    end-tag is provided as the third argument.

    The tag specifier consists of the following components (in order):

    An optional vertical spacer (zero or more whitespace-separated newlines)
        One or more whitespace characters up to a final mandatory newline.
        This vertical space is inserted before the tag and after the end-tag

    An optional tag indent
        Zero or more whitespace characters. Both the tag and the end-tag are
        indented by this whitespace.

    An optional left (opening) tag delimiter
        Zero or more non-"word" characters (not alphanumeric or '_'). If the
        opening delimiter is omitted, the character '<' is used.

    A tag
        One or more "word" characters (alphanumeric or '_').

    Optional tag arguments
        Any number of any characters

    An optional right (closing) tag delimiter
        Zero or more non-"word" characters which balance some sequential
        portion of the opening tag delimiter. For example, if the opening
        delimiter is "<-(" then any of the following are acceptible closing
        delimiters: ")->", "->", or ">". If the closing delimiter is
        omitted, the "inverse" of the opening delimiter is used (for
        example, ")->"),

    An optional vertical spacer (zero or more newlines)
        One or more whitespace characters up to a mandatory newline. This
        vertical space is inserted before and after the complete text.

    An optional text indent
        Zero or more space of tab characters. Each line of text is indented
        by this whitespace (in addition to the tag indent).

    For example:

            $text = "three lines\nof tagged\ntext";

            print tag "A HREF=#nextsection", $text;

    prints:

            <A HREF=#nextsection>three lines
            of tagged
            text</A>

    whereas:

            print tag "[-:GRIN>>>\n", $text;

    prints:

            [-:GRIN>>>:-]
            three lines
            of tagged
            text
            [-:/GRIN>>>:-]

    and:

            print tag "\n\n   <BOLD>\n\n   ", $text, "<END BOLD>";

    prints:



               <BOLD>

                  three lines
                  of tagged
                  text

               <END BOLD>



    (with the indicated spacing fore and aft).

AUTHOR
    Damian Conway (damian AT conway.org)

BUGS
    The module uses "POSIX::strtod", which may be broken under certain
    versions of Windows. Applying the WINDOWS_PATCH patch to Reform.pm will
    replace the POSIX function with a copycat subroutine.

    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.


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