man.pm

UNIX下perl实现代码

    $self->output ($$self{INDENT} > 0 ? ".Sp\n" : ".PP\n")
        if $$self{NEEDSPACE};
}

# Output any pending index entries, and optionally an index entry given as
# an argument.  Support multiple index entries in X<> separated by slashes,
# and strip special escapes from index entries.
sub outindex {
    my ($self, $section, $index) = @_;
    my @entries = map { split m%\s*/\s*% } @{ $$self{INDEX} };
    return unless ($section || @entries);
    $$self{INDEX} = [];
    my $output;
    if (@entries) {
        my $output = '.IX Xref "'
            . join (' ', map { s/\"/\"\"/; $_ } @entries)
            . '"' . "\n";
    }
    if ($section) {
        $index =~ s/\"/\"\"/;
        $index =~ s/\\-/-/g;
        $index =~ s/\\(?:s-?\d|.\(..|.)//g;
        $output .= ".IX $section " . '"' . $index . '"' . "\n";
    }
    $self->output ($output);
}

# Output text to the output device.
sub output { print { $_[0]->output_handle } $_[1] }

# Given a command and a single argument that may or may not contain double
# quotes, handle double-quote formatting for it.  If there are no double
# quotes, just return the command followed by the argument in double quotes.
# If there are double quotes, use an if statement to test for nroff, and for
# nroff output the command followed by the argument in double quotes with
# embedded double quotes doubled.  For other formatters, remap paired double
# quotes to LQUOTE and RQUOTE.
sub switchquotes {
    my $self = shift;
    my $command = shift;
    local $_ = shift;
    my $extra = shift;
    s/\\\*\([LR]\"/\"/g;

    # We also have to deal with \*C` and \*C', which are used to add the
    # quotes around C<> text, since they may expand to " and if they do this
    # confuses the .SH macros and the like no end.  Expand them ourselves.
    # If $extra is set, we're dealing with =item, which in most nroff macro
    # sets requires an extra level of quoting of double quotes.
    my $c_is_quote = ($$self{LQUOTE} =~ /\"/) || ($$self{RQUOTE} =~ /\"/);
    if (/\"/ || ($c_is_quote && /\\\*\(C[\'\`]/)) {
        s/\"/\"\"/g;
        my $troff = $_;
        $troff =~ s/\"\"([^\"]*)\"\"/\`\`$1\'\'/g;
        s/\\\*\(C\`/$$self{LQUOTE}/g;
        s/\\\*\(C\'/$$self{RQUOTE}/g;
        $troff =~ s/\\\*\(C[\'\`]//g;
        s/\"/\"\"/g if $extra;
        $troff =~ s/\"/\"\"/g if $extra;
        $_ = qq("$_") . ($extra ? " $extra" : '');
        $troff = qq("$troff") . ($extra ? " $extra" : '');
        return ".if n $command $_\n.el $command $troff\n";
    } else {
        $_ = qq("$_") . ($extra ? " $extra" : '');
        return "$command $_\n";
    }
}

__END__

.\" These are some extra bits of roff that I don't want to lose track of
.\" but that have been removed from the preamble to make it a bit shorter
.\" since they're not currently being used.  They're accents and special
.\" characters we don't currently have escapes for.
.if n \{\
.    ds ? ?
.    ds ! !
.    ds q
.\}
.if t \{\
.    ds ? \s-2c\h'-\w'c'u*7/10'\u\h'\*(#H'\zi\d\s+2\h'\w'c'u*8/10'
.    ds ! \s-2\(or\s+2\h'-\w'\(or'u'\v'-.8m'.\v'.8m'
.    ds q o\h'-\w'o'u*8/10'\s-4\v'.4m'\z\(*i\v'-.4m'\s+4\h'\w'o'u*8/10'
.\}
.ds v \\k:\h'-(\\n(.wu*9/10-\*(#H)'\v'-\*(#V'\*(#[\s-4v\s0\v'\*(#V'\h'|\\n:u'\*(#]
.ds _ \\k:\h'-(\\n(.wu*9/10-\*(#H+(\*(#F*2/3))'\v'-.4m'\z\(hy\v'.4m'\h'|\\n:u'
.ds . \\k:\h'-(\\n(.wu*8/10)'\v'\*(#V*4/10'\z.\v'-\*(#V*4/10'\h'|\\n:u'
.ds 3 \*(#[\v'.2m'\s-2\&3\s0\v'-.2m'\*(#]
.ds oe o\h'-(\w'o'u*4/10)'e
.ds Oe O\h'-(\w'O'u*4/10)'E
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds v \h'-1'\o'\(aa\(ga'
.    ds _ \h'-1'^
.    ds . \h'-1'.
.    ds 3 3
.    ds oe oe
.    ds Oe OE
.\}

############################################################################
# Documentation
############################################################################

=head1 NAME

Pod::Man - Convert POD data to formatted *roff input

=head1 SYNOPSIS

    use Pod::Man;
    my $parser = Pod::Man->new (release => $VERSION, section => 8);

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

    # Read POD from file.pod and write to file.1.
    $parser->parse_from_file ('file.pod', 'file.1');

=head1 DESCRIPTION

Pod::Man is a module to convert documentation in the POD format (the
preferred language for documenting Perl) into *roff input using the man
macro set.  The resulting *roff code is suitable for display on a terminal
using nroff(1), normally via man(1), or printing using troff(1).  It is
conventionally invoked using the driver script B<pod2man>, but it can also
be used directly.

As a derived class from Pod::Parser, Pod::Man supports the same methods and
interfaces.  See L<Pod::Parser> for all the details; briefly, one creates a
new parser with C<Pod::Man-E<gt>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.  See below for details.

If no options are given, Pod::Man uses the name of the input file with any
trailing C<.pod>, C<.pm>, or C<.pl> stripped as the man page title, to
section 1 unless the file ended in C<.pm> in which case it defaults to
section 3, to a centered title of "User Contributed Perl Documentation", to
a centered footer of the Perl version it is run with, and to a left-hand
footer of the modification date of its input (or the current date if given
STDIN for input).

Pod::Man assumes that your *roff formatters have a fixed-width font named
CW.  If yours is called something else (like CR), use the C<fixed> option to
specify it.  This generally only matters for troff output for printing.
Similarly, you can set the fonts used for bold, italic, and bold italic
fixed-width output.

Besides the obvious pod conversions, Pod::Man also takes care of formatting
func(), func(n), and simple variable references like $foo or @bar so you
don't have to use code escapes for them; complex expressions like
C<$fred{'stuff'}> will still need to be escaped, though.  It also translates
dashes that aren't used as hyphens into en dashes, makes long dashes--like
this--into proper em dashes, fixes "paired quotes," makes C++ and PI look
right, puts a little space between double underbars, makes ALLCAPS a teeny
bit smaller in troff(1), and escapes stuff that *roff treats as special so
that you don't have to.

The recognized options to new() are as follows.  All options take a single
argument.

=over 4

=item center

Sets the centered page header to use instead of "User Contributed Perl
Documentation".

=item date

Sets the left-hand footer.  By default, the modification date of the input
file will be used, or the current date if stat() can't find that file (the
case if the input is from STDIN), and the date will be formatted as
YYYY-MM-DD.

=item fixed

The fixed-width font to use for vertabim text and code.  Defaults to CW.
Some systems may want CR instead.  Only matters for troff(1) output.

=item fixedbold

Bold version of the fixed-width font.  Defaults to CB.  Only matters for
troff(1) output.

=item fixeditalic

Italic version of the fixed-width font (actually, something of a misnomer,
since most fixed-width fonts only have an oblique version, not an italic
version).  Defaults to CI.  Only matters for troff(1) output.

=item fixedbolditalic

Bold italic (probably actually oblique) version of the fixed-width font.
Pod::Man doesn't assume you have this, and defaults to CB.  Some systems
(such as Solaris) have this font available as CX.  Only matters for troff(1)
output.

=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 (but the font is still changed for troff
output).

=item release

Set the centered footer.  By default, this is the version of Perl you run
Pod::Man under.  Note that some system an macro sets assume that the
centered footer will be a modification date and will prepend something like
"Last modified: "; if this is the case, you may want to set C<release> to
the last modified date and C<date> to the version number.

=item section

Set the section for the C<.TH> macro.  The standard section numbering
convention is to use 1 for user commands, 2 for system calls, 3 for
functions, 4 for devices, 5 for file formats, 6 for games, 7 for
miscellaneous information, and 8 for administrator commands.  There is a lot
of variation here, however; some systems (like Solaris) use 4 for file
formats, 5 for miscellaneous information, and 7 for devices.  Still others
use 1m instead of 8, or some mix of both.  About the only section numbers
that are reliably consistent are 1, 2, and 3.

By default, section 1 will be used unless the file ends in .pm in which case
section 3 will be selected.

=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 roff font should be 1 or 2 chars, not "%s"

(F) You specified a *roff font (using C<fixed>, C<fixedbold>, etc.) that
wasn't either one or two characters.  Pod::Man doesn't support *roff fonts
longer than two characters, although some *roff extensions do (the canonical
versions of nroff(1) and troff(1) don't either).

=item Invalid link %s

(W) The POD source contained a C<LE<lt>E<gt>> sequence that Pod::Man was
unable to parse.  You should never see this error message; it probably
indicates a bug in Pod::Man.

=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 Unknown escape EE<lt>%sE<gt>

(W) The POD source contained an C<EE<lt>E<gt>> escape that Pod::Man didn't
know about.  C<EE<lt>%sE<gt>> was printed verbatim in the output.

=item Unknown sequence %s

(W) The POD source contained a non-standard interior sequence (something of
the form C<XE<lt>E<gt>>) that Pod::Man didn't know about.  It was ignored.

=item %s: Unknown command paragraph "%s" on line %d.

(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 Unmatched =back

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

=back

=head1 BUGS

The lint-like features and strict POD format checking done by B<pod2man> are
not yet implemented and should be, along with the corresponding C<lax>
option.

The NAME section should be recognized specially and index entries emitted
for everything in that section.  This would have to be deferred until the
next section, since extraneous things in NAME tends to confuse various man
page processors.

The handling of hyphens, en dashes, and em dashes is somewhat fragile, and
one may get the wrong one under some circumstances.  This should only matter
for troff(1) output.

When and whether to use small caps is somewhat tricky, and Pod::Man doesn't
necessarily get it right.

Pod::Man doesn't handle font names longer than two characters.  Neither do
most troff(1) implementations, but GNU troff does as an extension.  It would
be nice to support as an option for those who want to use it.

The preamble added to each output file is rather verbose, and most of it is
only necessary in the presence of EE<lt>E<gt> escapes for non-ASCII
characters.  It would ideally be nice if all of those definitions were only
output if needed, perhaps on the fly as the characters are used.

Some of the automagic applied to file names assumes Unix directory
separators.

Pod::Man is excessively slow.

=head1 SEE ALSO

L<Pod::Parser|Pod::Parser>, perlpod(1), pod2man(1), nroff(1), troff(1),
man(1), man(7)

Ossanna, Joseph F., and Brian W. Kernighan.  "Troff User's Manual,"
Computing Science Technical Report No. 54, AT&T Bell Laboratories.  This is
the best documentation of standard nroff(1) and troff(1).  At the time of
this writing, it's available at http://www.cs.bell-labs.com/cm/cs/cstr.html.

The man page documenting the man macro set may be man(5) instead of man(7)
on your system.  Also, please see pod2man(1) for extensive documentation on
writing manual pages if you've not done it before and aren't familiar with
the conventions.

=head1 AUTHOR

Russ Allbery E<lt>[e-mail]<gt>, based I<very> heavily on the
original B<pod2man> by Tom Christiansen E<lt>[e-mail]<gt>.

=cut