Mail::DKIM::TextWrap(3User Contributed Perl DocumentatiMail::DKIM::TextWrap(3)NAMEMail::DKIM::TextWrap - text wrapping module written for use with DKIM
SYNOPSIS (FOR MAIL::DKIM USERS)
use Mail::DKIM::TextWrap;
Just add the above line to any program that uses Mail::DKIM::Signer and
your signatures will automatically be wrapped to 72 characters.
SYNOPSIS (FOR OTHER USERS)
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-
wrapping options at the start and end of each tag.
TEXT WRAPPING OPTIONS
Text wrapping options can be specified when calling new(), or by simply
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/".
CONSTRUCTORnew() - 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
current 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.
METHODSadd() - 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 v5.18.1 2012-11-28 Mail::DKIM::TextWrap(3)
