Mail::DKIM::TextWrap

Mail::DKIM::TextWrap(User Contributed Perl DocumentatiMail::DKIM::TextWrap(3)



NAME
       Mail::DKIM::TextWrap - text wrapping module written for use with DKIM

SYNOPSIS
	 my $output = "";
	 my $tw = Mail::DKIM::TextWrap->new(
			 Margin => 10,
			 Output => \$output,
		     );
	 $tw->add("Mary had a little lamb, whose fleece was white as snow.\n");
	 $tw->finish;

	 print $output;

DESCRIPTION
       This is a general-purpose text-wrapping module that I wrote because I
       had some specific needs with Mail::DKIM that none of the contemporary
       text-wrapping modules offered.

       Specifically, it offers the ability to change wrapping options in the
       middle of a paragraph. For instance, with a DKIM signature:

	 DKIM-Signature: a=rsa; c=simple; h=first:second:third:fourth;
		 b=Xr2mo2wmb1LZBwmEJElIPezal7wQQkRQ8WZtxpofkNmXTjXf8y2f0

       the line-breaks can be inserted next to any of the colons of the h=
       tag, or any character of the b= tag. The way I implemented this was to
       serialize the signature one element at a time, changing the text-wrap-
       ping options at the start and end of each tag.

TEXT WRAPPING OPTIONS
       Text wrapping options can be specified when calling new(), or by sim-
       ply changing the property as needed. For example, to change the number
       of characters allowed per line:

	 $tw->{Margin} = 20;

       Break
	   a regular expression matching characters where a line break can be
	   inserted. Line breaks are inserted AFTER a matching substring.
	   The default is "/\s/".

       BreakBefore
	   a regular expression matching characters where a line break can be
	   inserted. Line breaks are inserted BEFORE a matching substring.
	   Usually, you want to use Break, rather than BreakBefore.  The
	   default is "undef".

       Margin
	   specifies how many characters to allow per line.  The default is
	   72. If no place to line-break is found on a line, the line will
	   extend beyond this margin.

       Separator
	   the text to insert when a linebreak is needed.  The default is
	   "\n". If you want to set a following-line indent (e.g. all lines
	   but the first begin with four spaces), use something like "\n
	   ".

       Swallow
	   a regular expression matching characters that can be omitted when
	   a line break occurs. For example, if you insert a line break
	   between two words, then you are replacing a "space" with the line
	   break, so you are omitting the space. On the other hand, if you
	   insert a line break between two parts of a hyphenated word, then
	   you are breaking at the hyphen, but you still want to display the
	   hyphen.  The default is "/\s/".

CONSTRUCTOR
       new() - create a new text-wrapping object

	 my $tw = Mail::DKIM::TextWrap->new(
			     Output => \$output,
			     %wrapping_options,
			 );

       The text-wrapping object encapsulates the current options and the cur-
       rent state of the text stream. In addition to specifying text wrapping
       options as described in the section above, the following options are
       recognized:

       Output
	   a scalar reference, or a glob reference, to specify where the
	   "wrapped" text gets output to. If not specified, the default of
	   STDOUT is used.

METHODS
       add() - process some text that can be wrapped

	 $tw->add("Mary had a little lamb.\n");

       You can add() all the text at once, or add() the text in parts by
       calling add() multiple times.

       finish() - call when no more text is to be added

	 $tw->finish;

       Call this when finished adding text, so that any remaining text in
       TextWrap’s buffers will be output.

       flush() - output the current partial word, if any

	 $tw->flush;

       Call this whenever changing TextWrap’s parameters in the middle of a
       string of words. It explicitly allows a line-break at the current
       position in the string, regardless of whether it matches the current
       break pattern.



perl v5.8.8			  2009-05-22	      Mail::DKIM::TextWrap(3)