text.pm

Astercon2 开源软交换 2.2.0

# Wrap a line, indenting by the current left margin.  We can't use Text::Wrap
# because it plays games with tabs.  We can't use formline, even though we'd
# really like to, because it screws up non-printing characters.  So we have to
# do the wrapping ourselves.
sub wrap {
    my $self = shift;
    local $_ = shift;
    my $output = '';
    my $spaces = ' ' x $$self{MARGIN};
    my $width = $$self{width} - $$self{MARGIN};
    while (length > $width) {
        if (s/^([^\n]{0,$width})\s+// || s/^([^\n]{$width})//) {
            $output .= $spaces . $1 . "\n";
        } else {
            last;
        }
    }
    $output .= $spaces . $_;
    $output =~ s/\s+$/\n\n/;
    $output;
}

# Reformat a paragraph of text for the current margin.  Takes the text to
# reformat and returns the formatted text.
sub reformat {
    my $self = shift;
    local $_ = shift;

    # If we're trying to preserve two spaces after sentences, do some munging
    # to support that.  Otherwise, smash all repeated whitespace.
    if ($$self{sentence}) {
        s/ +$//mg;
        s/\.\n/. \n/g;
        s/\n/ /g;
        s/   +/  /g;
    } else {
        s/\s+/ /g;
    }
    $self->wrap ($_);
}

# Output text to the output device.
sub output { $_[1] =~ tr/\01/ /; print { $_[0]->output_handle } $_[1] }

# Output a block of code (something that isn't part of the POD text).  Called
# by preprocess_paragraph only if we were given the code option.  Exists here
# only so that it can be overridden by subclasses.
sub output_code { $_[0]->output ($_[1]) }


##############################################################################
# Backwards compatibility
##############################################################################

# The old Pod::Text module did everything in a pod2text() function.  This
# tries to provide the same interface for legacy applications.
sub pod2text {
    my @args;

    # This is really ugly; I hate doing option parsing in the middle of a
    # module.  But the old Pod::Text module supported passing flags to its
    # entry function, so handle -a and -<number>.
    while ($_[0] =~ /^-/) {
        my $flag = shift;
        if    ($flag eq '-a')       { push (@args, alt => 1)    }
        elsif ($flag =~ /^-(\d+)$/) { push (@args, width => $1) }
        else {
            unshift (@_, $flag);
            last;
        }
    }

    # Now that we know what arguments we're using, create the parser.
    my $parser = Pod::Text->new (@args);

    # If two arguments were given, the second argument is going to be a file
    # handle.  That means we want to call parse_from_filehandle(), which means
    # we need to turn the first argument into a file handle.  Magic open will
    # handle the <&STDIN case automagically.
    if (defined $_[1]) {
        my @fhs = @_;
        local *IN;
        unless (open (IN, $fhs[0])) {
            croak ("Can't open $fhs[0] for reading: $!\n");
            return;
        }
        $fhs[0] = \*IN;
        return $parser->parse_from_filehandle (@fhs);
    } else {
        return $parser->parse_from_file (@_);
    }
}


##############################################################################
# Module return value and documentation
##############################################################################

1;
__END__

=head1 NAME

Pod::Text - Convert POD data to formatted ASCII text

=head1 SYNOPSIS

    use Pod::Text;
    my $parser = Pod::Text->new (sentence => 0, width => 78);

    # Read POD from STDIN and write to STDOUT.
    $parser->parse_from_filehandle;

    # Read POD from file.pod and write to file.txt.
    $parser->parse_from_file ('file.pod', 'file.txt');

=head1 DESCRIPTION

Pod::Text is a module that can convert documentation in the POD format (the
preferred language for documenting Perl) into formatted ASCII.  It uses no
special formatting controls or codes whatsoever, and its output is therefore
suitable for nearly any device.

As a derived class from Pod::Parser, Pod::Text supports the same methods and
interfaces.  See L<Pod::Parser> for all the details; briefly, one creates a
new parser with C<< Pod::Text->new() >> and then calls either
parse_from_filehandle() or parse_from_file().

new() can take options, in the form of key/value pairs, that control the
behavior of the parser.  The currently recognized options are:

=over 4

=item alt

If set to a true value, selects an alternate output format that, among other
things, uses a different heading style and marks C<=item> entries with a
colon in the left margin.  Defaults to false.

=item code

If set to a true value, the non-POD parts of the input file will be included
in the output.  Useful for viewing code documented with POD blocks with the
POD rendered and the code left intact.

=item indent

The number of spaces to indent regular text, and the default indentation for
C<=over> blocks.  Defaults to 4.

=item loose

If set to a true value, a blank line is printed after a C<=head1> heading.
If set to false (the default), no blank line is printed after C<=head1>,
although one is still printed after C<=head2>.  This is the default because
it's the expected formatting for manual pages; if you're formatting
arbitrary text documents, setting this to true may result in more pleasing
output.

=item margin

The width of the left margin in spaces.  Defaults to 0.  This is the margin
for all text, including headings, not the amount by which regular text is
indented; for the latter, see the I<indent> option.  To set the right
margin, see the I<width> option.

=item quotes

Sets the quote marks used to surround CE<lt>> text.  If the value is a
single character, it is used as both the left and right quote; if it is two
characters, the first character is used as the left quote and the second as
the right quoted; and if it is four characters, the first two are used as
the left quote and the second two as the right quote.

This may also be set to the special value C<none>, in which case no quote
marks are added around CE<lt>> text.

=item sentence

If set to a true value, Pod::Text will assume that each sentence ends in two
spaces, and will try to preserve that spacing.  If set to false, all
consecutive whitespace in non-verbatim paragraphs is compressed into a
single space.  Defaults to true.

=item width

The column at which to wrap text on the right-hand side.  Defaults to 76.

=back

The standard Pod::Parser method parse_from_filehandle() takes up to two
arguments, the first being the file handle to read POD from and the second
being the file handle to write the formatted output to.  The first defaults
to STDIN if not given, and the second defaults to STDOUT.  The method
parse_from_file() is almost identical, except that its two arguments are the
input and output disk files instead.  See L<Pod::Parser> for the specific
details.

=head1 DIAGNOSTICS

=over 4

=item Bizarre space in item

=item Item called without tag

(W) Something has gone wrong in internal C<=item> processing.  These
messages indicate a bug in Pod::Text; you should never see them.

=item Can't open %s for reading: %s

(F) Pod::Text was invoked via the compatibility mode pod2text() interface
and the input file it was given could not be opened.

=item Invalid quote specification "%s"

(F) The quote specification given (the quotes option to the constructor) was
invalid.  A quote specification must be one, two, or four characters long.

=item %s:%d: Unknown command paragraph: %s

(W) The POD source contained a non-standard command paragraph (something of
the form C<=command args>) that Pod::Man didn't know about.  It was ignored.

=item %s:%d: Unknown escape: %s

(W) The POD source contained an C<EE<lt>E<gt>> escape that Pod::Text didn't
know about.

=item %s:%d: Unknown formatting code: %s

(W) The POD source contained a non-standard formatting code (something of
the form C<XE<lt>E<gt>>) that Pod::Text didn't know about.

=item %s:%d: Unmatched =back

(W) Pod::Text encountered a C<=back> command that didn't correspond to an
C<=over> command.

=back

=head1 RESTRICTIONS

Embedded Ctrl-As (octal 001) in the input will be mapped to spaces on
output, due to an internal implementation detail.

=head1 NOTES

This is a replacement for an earlier Pod::Text module written by Tom
Christiansen.  It has a revamped interface, since it now uses Pod::Parser,
but an interface roughly compatible with the old Pod::Text::pod2text()
function is still available.  Please change to the new calling convention,
though.

The original Pod::Text contained code to do formatting via termcap
sequences, although it wasn't turned on by default and it was problematic to
get it to work at all.  This rewrite doesn't even try to do that, but a
subclass of it does.  Look for L<Pod::Text::Termcap>.

=head1 SEE ALSO

L<Pod::Parser>, L<Pod::Text::Termcap>, L<pod2text(1)>

The current version of this module is always available from its web site at
L<http://www.eyrie.org/~eagle/software/podlators/>.  It is also part of the
Perl core distribution as of 5.6.0.

=head1 AUTHOR

Russ Allbery <[e-mail]>, based I<very> heavily on the original
Pod::Text by Tom Christiansen <[e-mail]> and its conversion to
Pod::Parser by Brad Appleton <[e-mail]>.

=head1 COPYRIGHT AND LICENSE

Copyright 1999, 2000, 2001, 2002 by Russ Allbery <[e-mail]>.

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

=cut