#! /usr/bin/perl -w

#   Copyright (C) 1999, 2000, 2001, 2003 Free Software Foundation, Inc.

# This file is part of GCC.

# GCC is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2, or (at your option)

# any later version.

# GCC is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License

# along with GCC; see the file COPYING.  If not, write to

# the Free Software Foundation, 51 Franklin Street, Fifth Floor,

# Boston MA 02110-1301, USA.

# This does trivial (and I mean _trivial_) conversion of Texinfo

# markup to Perl POD format.  It's intended to be used to extract

# something suitable for a manpage from a Texinfo document.

$output = 0;

$skipping = 0;

%sects = ();

$section = "";

@icstack = ();

@endwstack = ();

@skstack = ();

@instack = ();

$shift = "";

%defs = ();

$fnno = 1;

$inf = "";

$ibase = "";

@ipath = ();

while ($_ = shift) {

    if (/^-D(.*)$/) {

	if ($1 ne "") {

	    $flag = $1;

	} else {

	    $flag = shift;

	}

	$value = "";

	($flag, $value) = ($flag =~ /^([^=]+)(?:=(.+))?/);

	die "no flag specified for -D\n"

	    unless $flag ne "";

	die "flags may only contain letters, digits, hyphens, dashes and underscores\n"

	    unless $flag =~ /^[a-zA-Z0-9_-]+$/;

	$defs{$flag} = $value;

    } elsif (/^-I(.*)$/) {

	if ($1 ne "") {

	    $flag = $1;

	} else {

	    $flag = shift;

	}

        push (@ipath, $flag);

    } elsif (/^-/) {

	usage();

    } else {

	$in = $_, next unless defined $in;

	$out = $_, next unless defined $out;

	usage();

    }

}

if (defined $in) {

    $inf = gensym();

    open($inf, "<$in") or die "opening \"$in\": $!\n";

    $ibase = $1 if $in =~ m|^(.+)/[^/]+$|;

} else {

    $inf = \*STDIN;

}

if (defined $out) {

    open(STDOUT, ">$out") or die "opening \"$out\": $!\n";

}

while(defined $inf) {

while(<$inf>) {

    # Certain commands are discarded without further processing.

    /^\@(?:

	 [a-z]+index		# @*index: useful only in complete manual

	 |need			# @need: useful only in printed manual

	 |(?:end\s+)?group	# @group .. @end group: ditto

	 |page			# @page: ditto

	 |node			# @node: useful only in .info file

	 |(?:end\s+)?ifnottex   # @ifnottex .. @end ifnottex: use contents

	)\b/x and next;

    chomp;

    # Look for filename and title markers.

    /^\@setfilename\s+([^.]+)/ and $fn = $1, next;

    /^\@settitle\s+([^.]+)/ and $tl = postprocess($1), next;

    # Identify a man title but keep only the one we are interested in.

    /^\@c\s+man\s+title\s+([A-Za-z0-9-]+)\s+(.+)/ and do {

	if (exists $defs{$1}) {

	    $fn = $1;

	    $tl = postprocess($2);

	}

	next;

    };

    # Look for blocks surrounded by @c man begin SECTION ... @c man end.

    # This really oughta be @ifman ... @end ifman and the like, but such

    # would require rev'ing all other Texinfo translators.

    /^\@c\s+man\s+begin\s+([A-Z]+)\s+([A-Za-z0-9-]+)/ and do {

	$output = 1 if exists $defs{$2};

        $sect = $1;

	next;

    };

    /^\@c\s+man\s+begin\s+([A-Z]+)/ and $sect = $1, $output = 1, next;

    /^\@c\s+man\s+end/ and do {

	$sects{$sect} = "" unless exists $sects{$sect};

	$sects{$sect} .= postprocess($section);

	$section = "";

	$output = 0;

	next;

    };

    # handle variables

    /^\@set\s+([a-zA-Z0-9_-]+)\s*(.*)$/ and do {

	$defs{$1} = $2;

	next;

    };

    /^\@clear\s+([a-zA-Z0-9_-]+)/ and do {

	delete $defs{$1};

	next;

    };

    next unless $output;

    # Discard comments.  (Can't do it above, because then we'd never see

    # @c man lines.)

    /^\@c\b/ and next;

    # End-block handler goes up here because it needs to operate even

    # if we are skipping.

    /^\@end\s+([a-z]+)/ and do {

	# Ignore @end foo, where foo is not an operation which may

	# cause us to skip, if we are presently skipping.

	my $ended = $1;

	next if $skipping && $ended !~ /^(?:ifset|ifclear|ignore|menu|iftex|copying)$/;

	die "\@end $ended without \@$ended at line $.\n" unless defined $endw;

	die "\@$endw ended by \@end $ended at line $.\n" unless $ended eq $endw;

	$endw = pop @endwstack;

	if ($ended =~ /^(?:ifset|ifclear|ignore|menu|iftex)$/) {

	    $skipping = pop @skstack;

	    next;

	} elsif ($ended =~ /^(?:example|smallexample|display)$/) {

	    $shift = "";

	    $_ = "";	# need a paragraph break

	} elsif ($ended =~ /^(?:itemize|enumerate|[fv]?table)$/) {

	    $_ = "\n=back\n";

	    $ic = pop @icstack;

	} elsif ($ended eq "multitable") {

	    $_ = "\n=back\n";

	} else {

	    die "unknown command \@end $ended at line $.\n";

	}

    };

    # We must handle commands which can cause skipping even while we

    # are skipping, otherwise we will not process nested conditionals

    # correctly.

    /^\@ifset\s+([a-zA-Z0-9_-]+)/ and do {

	push @endwstack, $endw;

	push @skstack, $skipping;

	$endw = "ifset";

	$skipping = 1 unless exists $defs{$1};

	next;

    };

    /^\@ifclear\s+([a-zA-Z0-9_-]+)/ and do {

	push @endwstack, $endw;

	push @skstack, $skipping;

	$endw = "ifclear";

	$skipping = 1 if exists $defs{$1};

	next;

    };

    /^\@(ignore|menu|iftex|copying)\b/ and do {

	push @endwstack, $endw;

	push @skstack, $skipping;

	$endw = $1;

	$skipping = 1;

	next;

    };

    next if $skipping;

    # Character entities.  First the ones that can be replaced by raw text

    # or discarded outright:

    s/\@copyright\{\}/(c)/g;

    s/\@dots\{\}/.../g;

    s/\@enddots\{\}/..../g;

    s/\@([.!? ])/$1/g;

    s/\@[:-]//g;

    s/\@bullet(?:\{\})?/*/g;

    s/\@TeX\{\}/TeX/g;

    s/\@pounds\{\}/\#/g;

    s/\@minus(?:\{\})?/-/g;

    s/\\,/,/g;

    # Now the ones that have to be replaced by special escapes

    # (which will be turned back into text by unmunge())

    s/&/&/g;

    s/\@\{/{/g;

    s/\@\}/}/g;

    s/\@\@/&at;/g;

    # Inside a verbatim block, handle @var specially.

    if ($shift ne "") {

	s/\@var\{([^\}]*)\}/<$1>/g;

    }

    # POD doesn't interpret E<> inside a verbatim block.

    if ($shift eq "") {

	s/</&lt;/g;

	s/>/>/g;

    } else {

	s/</&LT;/g;

	s/>/>/g;

    }

    # Single line command handlers.

    /^\@include\s+(.+)$/ and do {

	push @instack, $inf;

	$inf = gensym();

	$file = postprocess($1);

	# Try cwd and $ibase, then explicit -I paths.

	$done = 0;

	foreach $path ("", $ibase, @ipath) {

	    $mypath = $file;

	    $mypath = $path . "/" . $mypath if ($path ne "");

	    open($inf, "<" . $mypath) and ($done = 1, last);

	}

	die "cannot find $file" if !$done;

	next;

    };

    /^\@(?:section|unnumbered|unnumberedsec|center)\s+(.+)$/

	and $_ = "\n=head2 $1\n";

    /^\@subsection\s+(.+)$/

	and $_ = "\n=head3 $1\n";

    /^\@subsubsection\s+(.+)$/

	and $_ = "\n=head4 $1\n";

    # Block command handlers:

    /^\@itemize(?:\s+(\@[a-z]+|\*|-))?/ and do {

	push @endwstack, $endw;

	push @icstack, $ic;

	if (defined $1) {

	    $ic = $1;

	} else {

	    $ic = '*';

	}

	$_ = "\n=over 4\n";

	$endw = "itemize";

    };

    /^\@enumerate(?:\s+([a-zA-Z0-9]+))?/ and do {

	push @endwstack, $endw;

	push @icstack, $ic;

	if (defined $1) {

	    $ic = $1 . ".";

	} else {

	    $ic = "1.";

	}

	$_ = "\n=over 4\n";

	$endw = "enumerate";

    };

    /^\@multitable\s.*/ and do {

	push @endwstack, $endw;

	$endw = "multitable";

	$_ = "\n=over 4\n";

    };

    /^\@([fv]?table)\s+(\@[a-z]+)/ and do {

	push @endwstack, $endw;

	push @icstack, $ic;

	$endw = $1;

	$ic = $2;

	$ic =~ s/\@(?:samp|strong|key|gcctabopt|option|env)/B/;

	$ic =~ s/\@(?:code|kbd)/C/;

	$ic =~ s/\@(?:dfn|var|emph|cite|i)/I/;

	$ic =~ s/\@(?:file)/F/;

	$_ = "\n=over 4\n";

    };

    /^\@((?:small)?example|display)/ and do {

	push @endwstack, $endw;

	$endw = $1;

	$shift = "\t";

	$_ = "";	# need a paragraph break

    };

    /^\@item\s+(.*\S)\s*$/ and $endw eq "multitable" and do {

	@columns = ();

	for $column (split (/\s*\@tab\s*/, $1)) {

	    # @strong{...} is used a @headitem work-alike

	    $column =~ s/^\@strong{(.*)}$/$1/;

	    push @columns, $column;

	}

	$_ = "\n=item ".join (" : ", @columns)."\n";

    };

    /^\@itemx?\s*(.+)?$/ and do {

	if (defined $1) {

	    # Entity escapes prevent munging by the <> processing below.

	    $_ = "\n=item $ic\<$1\>\n";

	} else {

	    $_ = "\n=item $ic\n";

	    $ic =~ y/A-Ya-y/B-Zb-z/;

	    $ic =~ s/(\d+)/$1 + 1/eg;

	}

    };

    $section .= $shift.$_."\n";

}

# End of current file.

close($inf);

$inf = pop @instack;

}

die "No filename or title\n" unless defined $fn && defined $tl;

$sects{NAME} = "$fn \- $tl\n";

$sects{FOOTNOTES} .= "=back\n" if exists $sects{FOOTNOTES};

for $sect (qw(NAME SYNOPSIS DESCRIPTION OPTIONS ENVIRONMENT FILES

	      BUGS NOTES FOOTNOTES SEEALSO AUTHOR COPYRIGHT)) {

    if(exists $sects{$sect}) {

	$head = $sect;

	$head =~ s/SEEALSO/SEE ALSO/;

	print "=head1 $head\n\n";

	print scalar unmunge ($sects{$sect});

	print "\n";

    }

}

sub usage

{

    die "usage: $0 [-D toggle...] [infile [outfile]]\n";

}

sub postprocess

{

    local $_ = $_[0];

    # @value{foo} is replaced by whatever 'foo' is defined as.

    while (m/(\@value\{([a-zA-Z0-9_-]+)\})/g) {

	if (! exists $defs{$2}) {

	    print STDERR "Option $2 not defined\n";

	    s/\Q$1\E//;

	} else {

	    $value = $defs{$2};

	    s/\Q$1\E/$value/;

	}

    }

    # Formatting commands.

    # Temporary escape for @r.

    s/\@r\{([^\}]*)\}/R<$1>/g;

    s/\@(?:dfn|var|emph|cite|i)\{([^\}]*)\}/I<$1>/g;

    s/\@(?:code|kbd)\{([^\}]*)\}/C<$1>/g;

    s/\@(?:gccoptlist|samp|strong|key|option|env|command|b)\{([^\}]*)\}/B<$1>/g;

    s/\@sc\{([^\}]*)\}/\U$1/g;

    s/\@file\{([^\}]*)\}/F<$1>/g;

    s/\@w\{([^\}]*)\}/S<$1>/g;

    s/\@(?:dmn|math)\{([^\}]*)\}/$1/g;

    # keep references of the form @ref{...}, print them bold

    s/\@(?:ref)\{([^\}]*)\}/B<$1>/g;

    # Change double single quotes to double quotes.

    s/''/"/g;

    s/``/"/g;

    # Cross references are thrown away, as are @noindent and @refill.

    # (@noindent is impossible in .pod, and @refill is unnecessary.)

    # @* is also impossible in .pod; we discard it and any newline that

    # follows it.  Similarly, our macro @gol must be discarded.

    s/\(?\@xref\{(?:[^\}]*)\}(?:[^.<]|(?:<[^<>]*>))*\.\)?//g;

    s/\s+\(\@pxref\{(?:[^\}]*)\}\)//g;

    s/;\s+\@pxref\{(?:[^\}]*)\}//g;

    s/\@noindent\s*//g;

    s/\@refill//g;

    s/\@gol//g;

    s/\@\*\s*\n?//g;

    # Anchors are thrown away

    s/\@anchor\{(?:[^\}]*)\}//g;

    # @uref can take one, two, or three arguments, with different

    # semantics each time.  @url and @email are just like @uref with

    # one argument, for our purposes.

    s/\@(?:uref|url|email)\{([^\},]*)\}/&lt;B<$1>&gt;/g;

    s/\@uref\{([^\},]*),([^\},]*)\}/$2 (C<$1>)/g;

    s/\@uref\{([^\},]*),([^\},]*),([^\},]*)\}/$3/g;

    # Un-escape <> at this point.

    s/&LT;/</g;

    s/>/>/g;

    # Now un-nest all B<>, I<>, R<>.  Theoretically we could have

    # indefinitely deep nesting; in practice, one level suffices.

    1 while s/([BIR])<([^<>]*)([BIR])<([^<>]*)>/$1<$2>$3<$4>$1</g;

    # Replace R<...> with bare ...; eliminate empty markup, B<>;

    # shift white space at the ends of [BI]<...> expressions outside

    # the expression.

    s/R<([^<>]*)>/$1/g;

    s/[BI]<>//g;

    s/([BI])<(\s+)([^>]+)>/$2$1<$3>/g;

    s/([BI])<([^>]+?)(\s+)>/$1<$2>$3/g;

    # Extract footnotes.  This has to be done after all other

    # processing because otherwise the regexp will choke on formatting

    # inside @footnote.

    while (/\@footnote/g) {

	s/\@footnote\{([^\}]+)\}/[$fnno]/;

	add_footnote($1, $fnno);

	$fnno++;

    }

    return $_;

}

sub unmunge

{

    # Replace escaped symbols with their equivalents.

    local $_ = $_[0];

    s/&lt;/E<lt>/g;

    s/&gt;/E<gt>/g;

    s/{/\{/g;

    s/}/\}/g;

    s/&at;/\@/g;

    s/&/&/g;

    return $_;

}

sub add_footnote

{

    unless (exists $sects{FOOTNOTES}) {

	$sects{FOOTNOTES} = "\n=over 4\n\n";

    }

    $sects{FOOTNOTES} .= "=item $fnno.\n\n"; $fnno++;

    $sects{FOOTNOTES} .= $_[0];

    $sects{FOOTNOTES} .= "\n\n";

}

# stolen from Symbol.pm

{

    my $genseq = 0;

    sub gensym

    {

	my $name = "GEN" . $genseq++;

	my $ref = \*{$name};

	delete $::{$name};

	return $ref;

    }

}