path: root/lib/ExtUtils/xsubpp

#!./miniperl

=head1 NAME

xsubpp - compiler to convert Perl XS code into C code

=head1 SYNOPSIS

B<xsubpp> [B<-v>] [B<-C++>] [B<-except>] [B<-s pattern>] [B<-prototypes>] [B<-noversioncheck>] [B<-typemap typemap>]... file.xs

=head1 DESCRIPTION

I<xsubpp> will compile XS code into C code by embedding the constructs
necessary to let C functions manipulate Perl values and creates the glue
necessary to let Perl access those functions.  The compiler uses typemaps to
determine how to map C function parameters and variables to Perl values.

The compiler will search for typemap files called I<typemap>.  It will use
the following search path to find default typemaps, with the rightmost
typemap taking precedence.

	../../../typemap:../../typemap:../typemap:typemap

=head1 OPTIONS

=over 5

=item B<-C++>

Adds ``extern "C"'' to the C code.


=item B<-except>

Adds exception handling stubs to the C code.

=item B<-typemap typemap>

Indicates that a user-supplied typemap should take precedence over the
default typemaps.  This option may be used multiple times, with the last
typemap having the highest precedence.

=item B<-v>

Prints the I<xsubpp> version number to standard output, then exits.

=item B<-prototypes>

By default I<xsubpp> will not automatically generate prototype code for
all xsubs. This flag will enable prototypes.

=item B<-noversioncheck>

Disables the run time test that determines if the object file (derived
from the C<.xs> file) and the C<.pm> files have the same version
number.

=back

=head1 ENVIRONMENT

No environment variables are used.

=head1 AUTHOR

Larry Wall

=head1 MODIFICATION HISTORY

See the file F<changes.pod>.

=head1 SEE ALSO

perl(1), perlxs(1), perlxstut(1), perlapi(1)

=cut

# Global Constants
$XSUBPP_version = "1.937";
require 5.002;
use vars '$cplusplus';

sub Q ;

$FH = 'File0000' ;

$usage = "Usage: xsubpp [-v] [-C++] [-except] [-prototypes] [-noversioncheck] [-s pattern] [-typemap typemap]... file.xs\n";

$proto_re = "[" . quotemeta('\$%&*@;') . "]" ;

$except = "";
$WantPrototypes = -1 ;
$WantVersionChk = 1 ;
$ProtoUsed = 0 ;
SWITCH: while (@ARGV and $ARGV[0] =~ /^-./) {
    $flag = shift @ARGV;
    $flag =~ s/^-// ;
    $spat = shift,	next SWITCH	if $flag eq 's';
    $cplusplus = 1,	next SWITCH	if $flag eq 'C++';
    $WantPrototypes = 0, next SWITCH	if $flag eq 'noprototypes';
    $WantPrototypes = 1, next SWITCH	if $flag eq 'prototypes';
    $WantVersionChk = 0, next SWITCH	if $flag eq 'noversioncheck';
    $WantVersionChk = 1, next SWITCH	if $flag eq 'versioncheck';
    $except = " TRY",	next SWITCH	if $flag eq 'except';
    push(@tm,shift),	next SWITCH	if $flag eq 'typemap';
    (print "xsubpp version $XSUBPP_version\n"), exit  	
	if $flag eq 'v';
    die $usage;
}
if ($WantPrototypes == -1)
  { $WantPrototypes = 0}
else
  { $ProtoUsed = 1 }


@ARGV == 1 or die $usage;
($dir, $filename) = $ARGV[0] =~ m#(.*)/(.*)#
	or ($dir, $filename) = $ARGV[0] =~ m#(.*[>\]])(.*)#
	or ($dir, $filename) = ('.', $ARGV[0]);
chdir($dir);
# Check for VMS; Config.pm may not be installed yet, but this routine
# is built into VMS perl
if (defined(&VMS::Filespec::vmsify)) { $Is_VMS = 1; $pwd = $ENV{DEFAULT}; }
else                                 { $Is_VMS = 0; chomp($pwd = `pwd`);   }

++ $IncludedFiles{$ARGV[0]} ;

my(@XSStack) = ({type => 'none'});	# Stack of conditionals and INCLUDEs
my($XSS_work_idx, $cpp_next_tmp) = (0, "XSubPPtmpAAAA");

sub TrimWhitespace
{
    $_[0] =~ s/^\s+|\s+$//go ;
}

sub TidyType
{
    local ($_) = @_ ;

    # rationalise any '*' by joining them into bunches and removing whitespace
    s#\s*(\*+)\s*#$1#g;
    s#(\*+)# $1 #g ;

    # change multiple whitespace into a single space
    s/\s+/ /g ;
    
    # trim leading & trailing whitespace
    TrimWhitespace($_) ;

    $_ ;
}

$typemap = shift @ARGV;
foreach $typemap (@tm) {
    die "Can't find $typemap in $pwd\n" unless -r $typemap;
}
unshift @tm, qw(../../../../lib/ExtUtils/typemap ../../../lib/ExtUtils/typemap
                ../../lib/ExtUtils/typemap ../../../typemap ../../typemap
                ../typemap typemap);
foreach $typemap (@tm) {
    next unless -e $typemap ;
    # skip directories, binary files etc.
    warn("Warning: ignoring non-text typemap file '$typemap'\n"), next 
	unless -T $typemap ;
    open(TYPEMAP, $typemap) 
	or warn ("Warning: could not open typemap file '$typemap': $!\n"), next;
    $mode = 'Typemap';
    $junk = "" ;
    $current = \$junk;
    while (<TYPEMAP>) {
	next if /^\s*#/;
	if (/^INPUT\s*$/)   { $mode = 'Input';   $current = \$junk;  next; }
	if (/^OUTPUT\s*$/)  { $mode = 'Output';  $current = \$junk;  next; }
	if (/^TYPEMAP\s*$/) { $mode = 'Typemap'; $current = \$junk;  next; }
	if ($mode eq 'Typemap') {
	    chomp;
	    my $line = $_ ;
            TrimWhitespace($_) ;
	    # skip blank lines and comment lines
	    next if /^$/ or /^#/ ;
	    my($type,$kind, $proto) = /^\s*(.*?\S)\s+(\S+)\s*($proto_re*)\s*$/ or
		warn("Warning: File '$typemap' Line $. '$line' TYPEMAP entry needs 2 or 3 columns\n"), next;
            $type = TidyType($type) ;
	    $type_kind{$type} = $kind ;
            # prototype defaults to '$'
            $proto = "\$" unless $proto ;
            warn("Warning: File '$typemap' Line $. '$line' Invalid prototype '$proto'\n") 
                unless ValidProtoString($proto) ;
            $proto_letter{$type} = C_string($proto) ;
	}
	elsif (/^\s/) {
	    $$current .= $_;
	}
	elsif ($mode eq 'Input') {
	    s/\s+$//;
	    $input_expr{$_} = '';
	    $current = \$input_expr{$_};
	}
	else {
	    s/\s+$//;
	    $output_expr{$_} = '';
	    $current = \$output_expr{$_};
	}
    }
    close(TYPEMAP);
}

foreach $key (keys %input_expr) {
    $input_expr{$key} =~ s/\n+$//;
}

$END = "!End!\n\n";		# "impossible" keyword (multiple newline)

# Match an XS keyword
$BLOCK_re= '\s*(' . join('|', qw(
	REQUIRE BOOT CASE PREINIT INPUT INIT CODE PPCODE OUTPUT 
	CLEANUP ALIAS PROTOTYPES PROTOTYPE VERSIONCHECK INCLUDE
	)) . "|$END)\\s*:";

# Input:  ($_, @line) == unparsed input.
# Output: ($_, @line) == (rest of line, following lines).
# Return: the matched keyword if found, otherwise 0
sub check_keyword {
	$_ = shift(@line) while !/\S/ && @line;
	s/^(\s*)($_[0])\s*:\s*(?:#.*)?/$1/s && $2;
}


sub print_section {
    $_ = shift(@line) while !/\S/ && @line;
    for (;  defined($_) && !/^$BLOCK_re/o;  $_ = shift(@line)) {
	print "$_\n";
    }
}

sub process_keyword($)
{
    my($pattern) = @_ ;
    my $kwd ;

    &{"${kwd}_handler"}() 
        while $kwd = check_keyword($pattern) ;
}

sub CASE_handler {
    blurt ("Error: `CASE:' after unconditional `CASE:'")
	if $condnum && $cond eq '';
    $cond = $_;
    TrimWhitespace($cond);
    print "   ", ($condnum++ ? " else" : ""), ($cond ? " if ($cond)\n" : "\n");
    $_ = '' ;
}

sub INPUT_handler {
    for (;  !/^$BLOCK_re/o;  $_ = shift(@line)) {
	last if /^\s*NOT_IMPLEMENTED_YET/;
	next unless /\S/;	# skip blank lines 

	TrimWhitespace($_) ;
	my $line = $_ ;

	# remove trailing semicolon if no initialisation
	s/\s*;$//g unless /=/ ;

	# check for optional initialisation code
	my $var_init = '' ;
	$var_init = $1 if s/\s*(=.*)$//s ;
	$var_init =~ s/"/\\"/g;

	s/\s+/ /g;
	my ($var_type, $var_addr, $var_name) = /^(.*?[^& ]) *(\&?) *\b(\w+)$/s
	    or blurt("Error: invalid argument declaration '$line'"), next;

	# Check for duplicate definitions
	blurt ("Error: duplicate definition of argument '$var_name' ignored"), next
	    if $arg_list{$var_name} ++  ;

	$thisdone |= $var_name eq "THIS";
	$retvaldone |= $var_name eq "RETVAL";
	$var_types{$var_name} = $var_type;
	print "\t" . &map_type($var_type);
	$var_num = $args_match{$var_name};

        $proto_arg[$var_num] = ProtoString($var_type) 
	    if $var_num ;
	if ($var_addr) {
	    $var_addr{$var_name} = 1;
	    $func_args =~ s/\b($var_name)\b/&$1/;
	}
	if ($var_init =~ /^=\s*NO_INIT\s*;?\s*$/) {
	    print "\t$var_name;\n";
	} elsif ($var_init =~ /\S/) {
	    &output_init($var_type, $var_num, "$var_name $var_init");
	} elsif ($var_num) {
	    # generate initialization code
	    &generate_init($var_type, $var_num, $var_name);
	} else {
	    print ";\n";
	}
    }
}

sub OUTPUT_handler {
    for (;  !/^$BLOCK_re/o;  $_ = shift(@line)) {
	next unless /\S/;
	my ($outarg, $outcode) = /^\s*(\S+)\s*(.*?)\s*$/s ;
	blurt ("Error: duplicate OUTPUT argument '$outarg' ignored"), next
	    if $outargs{$outarg} ++ ;
	if (!$gotRETVAL and $outarg eq 'RETVAL') {
	    # deal with RETVAL last
	    $RETVAL_code = $outcode ;
	    $gotRETVAL = 1 ;
	    next ;
	}
	blurt ("Error: OUTPUT $outarg not an argument"), next
	    unless defined($args_match{$outarg});
	blurt("Error: No input definition for OUTPUT argument '$outarg' - ignored"), next
	    unless defined $var_types{$outarg} ;
	if ($outcode) {
	    print "\t$outcode\n";
	} else {
	    $var_num = $args_match{$outarg};
	    &generate_output($var_types{$outarg}, $var_num, $outarg); 
	}
    }
}

sub CLEANUP_handler() { print_section() } 
sub PREINIT_handler() { print_section() } 
sub INIT_handler()    { print_section() } 

sub GetAliases
{
    my ($line) = @_ ;
    my ($orig) = $line ;
    my ($alias) ;
    my ($value) ;

    # Parse alias definitions
    # format is
    #    alias = value alias = value ...

    while ($line =~ s/^\s*([\w:]+)\s*=\s*(\w+)\s*//) {
        $alias = $1 ;
        $orig_alias = $alias ;
        $value = $2 ;

        # check for optional package definition in the alias
	$alias = $Packprefix . $alias if $alias !~ /::/ ;
        
        # check for duplicate alias name & duplicate value
	Warn("Warning: Ignoring duplicate alias '$orig_alias'")
	    if defined $XsubAliases{$alias} ;

	Warn("Warning: Aliases '$orig_alias' and '$XsubAliasValues{$value}' have identical values")
	    if $XsubAliasValues{$value} ;

	$XsubAliases = 1;
	$XsubAliases{$alias} = $value ;
	$XsubAliasValues{$value} = $orig_alias ;
    }

    blurt("Error: Cannot parse ALIAS definitions from '$orig'")
        if $line ;
}

sub ALIAS_handler ()
{
    for (;  !/^$BLOCK_re/o;  $_ = shift(@line)) {
	next unless /\S/;
	TrimWhitespace($_) ;
        GetAliases($_) if $_ ;
    }
}

sub REQUIRE_handler ()
{
    # the rest of the current line should contain a version number
    my ($Ver) = $_ ;

    TrimWhitespace($Ver) ;

    death ("Error: REQUIRE expects a version number")
	unless $Ver ;

    # check that the version number is of the form n.n
    death ("Error: REQUIRE: expected a number, got '$Ver'")
	unless $Ver =~ /^\d+(\.\d*)?/ ;

    death ("Error: xsubpp $Ver (or better) required--this is only $XSUBPP_version.")
        unless $XSUBPP_version >= $Ver ; 
}

sub VERSIONCHECK_handler ()
{
    # the rest of the current line should contain either ENABLE or
    # DISABLE
 
    TrimWhitespace($_) ;
 
    # check for ENABLE/DISABLE
    death ("Error: VERSIONCHECK: ENABLE/DISABLE")
        unless /^(ENABLE|DISABLE)/i ;
 
    $WantVersionChk = 1 if $1 eq 'ENABLE' ;
    $WantVersionChk = 0 if $1 eq 'DISABLE' ;
 
}

sub PROTOTYPE_handler ()
{
    my $specified ;

    death("Error: Only 1 PROTOTYPE definition allowed per xsub") 
        if $proto_in_this_xsub ++ ;

    for (;  !/^$BLOCK_re/o;  $_ = shift(@line)) {
	next unless /\S/;
	$specified = 1 ;
	TrimWhitespace($_) ;
        if ($_ eq 'DISABLE') {
	   $ProtoThisXSUB = 0 
        }
        elsif ($_ eq 'ENABLE') {
	   $ProtoThisXSUB = 1 
        }
        else {
            # remove any whitespace
            s/\s+//g ;
            death("Error: Invalid prototype '$_'")
                unless ValidProtoString($_) ;
            $ProtoThisXSUB = C_string($_) ;
        }
    }

    # If no prototype specified, then assume empty prototype ""
    $ProtoThisXSUB = 2 unless $specified ;

    $ProtoUsed = 1 ;

}

sub PROTOTYPES_handler ()
{
    # the rest of the current line should contain either ENABLE or
    # DISABLE 

    TrimWhitespace($_) ;

    # check for ENABLE/DISABLE
    death ("Error: PROTOTYPES: ENABLE/DISABLE")
        unless /^(ENABLE|DISABLE)/i ;

    $WantPrototypes = 1 if $1 eq 'ENABLE' ;
    $WantPrototypes = 0 if $1 eq 'DISABLE' ;
    $ProtoUsed = 1 ;

}

sub INCLUDE_handler ()
{
    # the rest of the current line should contain a valid filename
 
    TrimWhitespace($_) ;
 
    death("INCLUDE: filename missing")
        unless $_ ;

    death("INCLUDE: output pipe is illegal")
        if /^\s*\|/ ;

    # simple minded recursion detector
    death("INCLUDE loop detected")
        if $IncludedFiles{$_} ;

    ++ $IncludedFiles{$_} unless /\|\s*$/ ;

    # Save the current file context.
    push(@XSStack, {
	type		=> 'file',
        LastLine        => $lastline,
        LastLineNo      => $lastline_no,
        Line            => \@line,
        LineNo          => \@line_no,
        Filename        => $filename,
        Handle          => $FH,
        }) ;
 
    ++ $FH ;

    # open the new file
    open ($FH, "$_") or death("Cannot open '$_': $!") ;
 
    print Q<<"EOF" ;
#
#/* INCLUDE:  Including '$_' from '$filename' */
#
EOF

    $filename = $_ ;

    # Prime the pump by reading the first 
    # non-blank line

    # skip leading blank lines
    while (<$FH>) {
        last unless /^\s*$/ ;
    }

    $lastline = $_ ;
    $lastline_no = $. ;
 
}
 
sub PopFile()
{
    return 0 unless $XSStack[-1]{type} eq 'file' ;

    my $data     = pop @XSStack ;
    my $ThisFile = $filename ;
    my $isPipe   = ($filename =~ /\|\s*$/) ;
 
    -- $IncludedFiles{$filename}
        unless $isPipe ;

    close $FH ;

    $FH         = $data->{Handle} ;
    $filename   = $data->{Filename} ;
    $lastline   = $data->{LastLine} ;
    $lastline_no = $data->{LastLineNo} ;
    @line       = @{ $data->{Line} } ;
    @line_no    = @{ $data->{LineNo} } ;

    if ($isPipe and $? ) {
        -- $lastline_no ;
        print STDERR "Error reading from pipe '$ThisFile': $! in $filename, line $lastline_no\n"  ;
        exit 1 ;
    }

    print Q<<"EOF" ;
#
#/* INCLUDE: Returning to '$filename' from '$ThisFile' */
#
EOF

    return 1 ;
}

sub ValidProtoString ($)
{
    my($string) = @_ ;

    if ( $string =~ /^$proto_re+$/ ) {
        return $string ;
    }

    return 0 ;
}

sub C_string ($)
{
    my($string) = @_ ;

    $string =~ s[\\][\\\\]g ;
    $string ;
}

sub ProtoString ($)
{
    my ($type) = @_ ;

    $proto_letter{$type} or "\$" ;
}

sub check_cpp {
    my @cpp = grep(/^\#\s*(?:if|e\w+)/, @line);
    if (@cpp) {
	my ($cpp, $cpplevel);
	for $cpp (@cpp) {
	    if ($cpp =~ /^\#\s*if/) {
		$cpplevel++;
	    } elsif (!$cpplevel) {
		Warn("Warning: #else/elif/endif without #if in this function");
		print STDERR "    (precede it with a blank line if the matching #if is outside the function)\n"
		    if $XSStack[-1]{type} eq 'if';
		return;
	    } elsif ($cpp =~ /^\#\s*endif/) {
		$cpplevel--;
	    }
	}
	Warn("Warning: #if without #endif in this function") if $cpplevel;
    }
}


sub Q {
    my($text) = @_;
    $text =~ s/^#//gm;
    $text =~ s/\[\[/{/g;
    $text =~ s/\]\]/}/g;
    $text;
}

open($FH, $filename) or die "cannot open $filename: $!\n";

# Identify the version of xsubpp used
print <<EOM ;
/*
 * This file was generated automatically by xsubpp version $XSUBPP_version from the 
 * contents of $filename. Do not edit this file, edit $filename instead.
 *
 *	ANY CHANGES MADE HERE WILL BE LOST! 
 *
 */

EOM
 

while (<$FH>) {
    last if ($Module, $Package, $Prefix) =
	/^MODULE\s*=\s*([\w:]+)(?:\s+PACKAGE\s*=\s*([\w:]+))?(?:\s+PREFIX\s*=\s*(\S+))?\s*$/;
    print $_;
}
&Exit unless defined $_;

$lastline    = $_;
$lastline_no = $.;


# Read next xsub into @line from ($lastline, <$FH>).
sub fetch_para {
    # parse paragraph
    death ("Error: Unterminated `#if/#ifdef/#ifndef'")
	if !defined $lastline && $XSStack[-1]{type} eq 'if';
    @line = ();
    @line_no = () ;
    return PopFile() if !defined $lastline;

    if ($lastline =~
	/^MODULE\s*=\s*([\w:]+)(?:\s+PACKAGE\s*=\s*([\w:]+))?(?:\s+PREFIX\s*=\s*(\S+))?\s*$/) {
	$Module = $1;
	$Package = defined($2) ? $2 : '';	# keep -w happy
	$Prefix  = defined($3) ? $3 : '';	# keep -w happy
	($Module_cname = $Module) =~ s/\W/_/g;
	($Packid = $Package) =~ tr/:/_/;
	$Packprefix = $Package;
	$Packprefix .= "::" if $Packprefix ne "";
	$lastline = "";
    }

    for(;;) {
	if ($lastline !~ /^\s*#/ ||
	    # CPP directives:
	    #	ANSI:	if ifdef ifndef elif else endif define undef
	    #		line error pragma
	    #	gcc:	warning include_next
	    #   obj-c:	import
	    #   others:	ident (gcc notes that some cpps have this one)
	    $lastline =~ /^#[ \t]*(?:(?:if|ifn?def|elif|else|endif|define|undef|pragma|error|warning|line\s+\d+|ident)\b|(?:include(?:_next)?|import)\s*["<].*[>"])/) {
	    last if $lastline =~ /^\S/ && @line && $line[-1] eq "";
	    push(@line, $lastline);
	    push(@line_no, $lastline_no) ;
	}

	# Read next line and continuation lines
	last unless defined($lastline = <$FH>);
	$lastline_no = $.;
	my $tmp_line;
	$lastline .= $tmp_line
	    while ($lastline =~ /\\$/ && defined($tmp_line = <$FH>));
	    
	chomp $lastline;
	$lastline =~ s/^\s+$//;
    }
    pop(@line), pop(@line_no) while @line && $line[-1] eq "";
    1;
}

PARAGRAPH:
while (fetch_para()) {
    # Print initial preprocessor statements and blank lines
    while (@line && $line[0] !~ /^[^\#]/) {
	my $line = shift(@line);
	print $line, "\n";
	next unless $line =~ /^\#\s*((if)(?:n?def)?|elsif|else|endif)\b/;
	my $statement = $+;
	if ($statement eq 'if') {
	    $XSS_work_idx = @XSStack;
	    push(@XSStack, {type => 'if'});
	} else {
	    death ("Error: `$statement' with no matching `if'")
		if $XSStack[-1]{type} ne 'if';
	    if ($XSStack[-1]{varname}) {
		push(@InitFileCode, "#endif\n");
		push(@BootCode,     "#endif");
	    }

	    my(@fns) = keys %{$XSStack[-1]{functions}};
	    if ($statement ne 'endif') {
		# Hide the functions defined in other #if branches, and reset.
		@{$XSStack[-1]{other_functions}}{@fns} = (1) x @fns;
		@{$XSStack[-1]}{qw(varname functions)} = ('', {});
	    } else {
		my($tmp) = pop(@XSStack);
		0 while (--$XSS_work_idx
			 && $XSStack[$XSS_work_idx]{type} ne 'if');
		# Keep all new defined functions
		push(@fns, keys %{$tmp->{other_functions}});
		@{$XSStack[$XSS_work_idx]{functions}}{@fns} = (1) x @fns;
	    }
	}
    }

    next PARAGRAPH unless @line;

    if ($XSS_work_idx && !$XSStack[$XSS_work_idx]{varname}) {
	# We are inside an #if, but have not yet #defined its xsubpp variable.
	print "#define $cpp_next_tmp 1\n\n";
	push(@InitFileCode, "#if $cpp_next_tmp\n");
	push(@BootCode,     "#if $cpp_next_tmp");
	$XSStack[$XSS_work_idx]{varname} = $cpp_next_tmp++;
    }

    death ("Code is not inside a function")
	if $line[0] =~ /^\s/;

    # initialize info arrays
    undef(%args_match);
    undef(%var_types);
    undef(%var_addr);
    undef(%defaults);
    undef($class);
    undef($static);
    undef($elipsis);
    undef($wantRETVAL) ;
    undef(%arg_list) ;
    undef(@proto_arg) ;
    undef($proto_in_this_xsub) ;
    $ProtoThisXSUB = $WantPrototypes ;

    $_ = shift(@line);
    while ($kwd = check_keyword("REQUIRE|PROTOTYPES|VERSIONCHECK|INCLUDE")) {
        &{"${kwd}_handler"}() ;
        next PARAGRAPH unless @line ;
        $_ = shift(@line);
    }

    if (check_keyword("BOOT")) {
	&check_cpp;
        push (@BootCode, $_, @line, "") ;
        next PARAGRAPH ;
    }


    # extract return type, function name and arguments
    my($ret_type) = TidyType($_);

    # a function definition needs at least 2 lines
    blurt ("Error: Function definition too short '$ret_type'"), next PARAGRAPH
	unless @line ;

    $static = 1 if $ret_type =~ s/^static\s+//;

    $func_header = shift(@line);
    blurt ("Error: Cannot parse function definition from '$func_header'"), next PARAGRAPH
	unless $func_header =~ /^(?:([\w:]*)::)?(\w+)\s*\(\s*(.*?)\s*\)\s*$/s;

    ($class, $func_name, $orig_args) =  ($1, $2, $3) ;
    ($pname = $func_name) =~ s/^($Prefix)?/$Packprefix/;
    $Full_func_name = "${Packid}_$func_name";

    # Check for duplicate function definition
    for $tmp (@XSStack) {
	next unless defined $tmp->{functions}{$Full_func_name};
	Warn("Warning: duplicate function definition '$func_name' detected");
	last;
    }
    $XSStack[$XSS_work_idx]{functions}{$Full_func_name} ++ ;
    %XsubAliases = %XsubAliasValues = ();

    @args = split(/\s*,\s*/, $orig_args);
    if (defined($class)) {
	my $arg0 = ((defined($static) or $func_name =~ /^new/) ? "CLASS" : "THIS");
	unshift(@args, $arg0);
	($orig_args = "$arg0, $orig_args") =~ s/^$arg0, $/$arg0/;
    }
    $orig_args =~ s/"/\\"/g;
    $min_args = $num_args = @args;
    foreach $i (0..$num_args-1) {
	    if ($args[$i] =~ s/\.\.\.//) {
		    $elipsis = 1;
		    $min_args--;
		    if ($args[$i] eq '' && $i == $num_args - 1) {
			pop(@args);
			last;
		    }
	    }
	    if ($args[$i] =~ /^([^=]*[^\s=])\s*=\s*(.*)/s) {
		    $min_args--;
		    $args[$i] = $1;
		    $defaults{$args[$i]} = $2;
		    $defaults{$args[$i]} =~ s/"/\\"/g;
	    }
	    $proto_arg[$i+1] = "\$" ;
    }
    if (defined($class)) {
	    $func_args = join(", ", @args[1..$#args]);
    } else {
	    $func_args = join(", ", @args);
    }
    @args_match{@args} = 1..@args;

    $PPCODE = grep(/^\s*PPCODE\s*:/, @line);
    $CODE = grep(/^\s*CODE\s*:/, @line);
    $ALIAS  = grep(/^\s*ALIAS\s*:/,  @line);

    # print function header
    print Q<<"EOF";
#XS(XS_${Packid}_$func_name)
#[[
#    dXSARGS;
EOF
    print Q<<"EOF" if $ALIAS ;
#    dXSI32;
EOF
    if ($elipsis) {
	$cond = ($min_args ? qq(items < $min_args) : 0);
    }
    elsif ($min_args == $num_args) {
	$cond = qq(items != $min_args);
    }
    else {
	$cond = qq(items < $min_args || items > $num_args);
    }

    print Q<<"EOF" if $except;
#    char errbuf[1024];
#    *errbuf = '\0';
EOF

    if ($ALIAS) 
      { print Q<<"EOF" if $cond }
#    if ($cond)
#       croak("Usage: %s($orig_args)", GvNAME(CvGV(cv)));
EOF
    else 
      { print Q<<"EOF" if $cond }
#    if ($cond)
#	croak("Usage: $pname($orig_args)");
EOF

    print Q<<"EOF" if $PPCODE;
#    SP -= items;
EOF

    # Now do a block of some sort.

    $condnum = 0;
    $cond = '';			# last CASE: condidional
    push(@line, "$END:");
    push(@line_no, $line_no[-1]);
    $_ = '';
    &check_cpp;
    while (@line) {
	&CASE_handler if check_keyword("CASE");
	print Q<<"EOF";
#   $except [[
EOF

	# do initialization of input variables
	$thisdone = 0;
	$retvaldone = 0;
	$deferred = "";
	%arg_list = () ;
        $gotRETVAL = 0;

	INPUT_handler() ;
	process_keyword("INPUT|PREINIT|ALIAS|PROTOTYPE") ;

	if (!$thisdone && defined($class)) {
	    if (defined($static) or $func_name =~ /^new/) {
		print "\tchar *";
		$var_types{"CLASS"} = "char *";
		&generate_init("char *", 1, "CLASS");
	    }
	    else {
		print "\t$class *";
		$var_types{"THIS"} = "$class *";
		&generate_init("$class *", 1, "THIS");
	    }
	}

	# do code
	if (/^\s*NOT_IMPLEMENTED_YET/) {
		print "\n\tcroak(\"$pname: not implemented yet\");\n";
		$_ = '' ;
	} else {
		if ($ret_type ne "void") {
			print "\t" . &map_type($ret_type) . "\tRETVAL;\n"
				if !$retvaldone;
			$args_match{"RETVAL"} = 0;
			$var_types{"RETVAL"} = $ret_type;
		}
		print $deferred;
                process_keyword("INIT|ALIAS|PROTOTYPE") ;

		if (check_keyword("PPCODE")) {
			print_section();
			death ("PPCODE must be last thing") if @line;
			print "\tPUTBACK;\n\treturn;\n";
		} elsif (check_keyword("CODE")) {
			print_section() ;
		} elsif (defined($class) and $func_name eq "DESTROY") {
			print "\n\t";
			print "delete THIS;\n";
		} else {
			print "\n\t";
			if ($ret_type ne "void") {
				print "RETVAL = ";
				$wantRETVAL = 1;
			}
			if (defined($static)) {
			    if ($func_name =~ /^new/) {
				$func_name = "$class";
			    } else {
				print "${class}::";
			    }
			} elsif (defined($class)) {
			    if ($func_name =~ /^new/) {
				$func_name .= " $class";
			    } else {
				print "THIS->";
			    }
			}
			$func_name =~ s/^($spat)//
			    if defined($spat);
			print "$func_name($func_args);\n";
		}
	}

	# do output variables
	$gotRETVAL = 0;
	undef $RETVAL_code ;
	undef %outargs ;
        process_keyword("OUTPUT|ALIAS|PROTOTYPE"); 

	# all OUTPUT done, so now push the return value on the stack
	if ($gotRETVAL && $RETVAL_code) {
	    print "\t$RETVAL_code\n";
	} elsif ($gotRETVAL || $wantRETVAL) {
	    &generate_output($ret_type, 0, 'RETVAL');
	}

	# do cleanup
	process_keyword("CLEANUP|ALIAS|PROTOTYPE") ;

	# print function trailer
	print Q<<EOF;
#    ]]
EOF
	print Q<<EOF if $except;
#    BEGHANDLERS
#    CATCHALL
#	sprintf(errbuf, "%s: %s\\tpropagated", Xname, Xreason);
#    ENDHANDLERS
EOF
	if (check_keyword("CASE")) {
	    blurt ("Error: No `CASE:' at top of function")
		unless $condnum;
	    $_ = "CASE: $_";	# Restore CASE: label
	    next;
	}
	last if $_ eq "$END:";
	death(/^$BLOCK_re/o ? "Misplaced `$1:'" : "Junk at end of function");
    }

    print Q<<EOF if $except;
#    if (errbuf[0])
#	croak(errbuf);
EOF

    if ($ret_type ne "void" or $CODE) {
        print Q<<EOF unless $PPCODE;
#    XSRETURN(1);
EOF
    } else {
        print Q<<EOF unless $PPCODE;
#    XSRETURN_EMPTY;
EOF
    }

    print Q<<EOF;
#]]
#
EOF

    my $newXS = "newXS" ;
    my $proto = "" ;

    # Build the prototype string for the xsub
    if ($ProtoThisXSUB) {
	$newXS = "newXSproto";

	if ($ProtoThisXSUB == 2) {
	    # User has specified empty prototype
	    $proto = ', ""' ;
	}
        elsif ($ProtoThisXSUB != 1) {
            # User has specified a prototype
            $proto = ', "' . $ProtoThisXSUB . '"';
        }
        else {
	    my $s = ';';
            if ($min_args < $num_args)  {
                $s = ''; 
		$proto_arg[$min_args] .= ";" ;
	    }
            push @proto_arg, "$s\@" 
                if $elipsis ;
    
            $proto = ', "' . join ("", @proto_arg) . '"';
        }
    }

    if (%XsubAliases) {
	$XsubAliases{$pname} = 0 
	    unless defined $XsubAliases{$pname} ;
	while ( ($name, $value) = each %XsubAliases) {
	    push(@InitFileCode, Q<<"EOF");
#        cv = newXS(\"$name\", XS_$Full_func_name, file);
#        XSANY.any_i32 = $value ;
EOF
	push(@InitFileCode, Q<<"EOF") if $proto;
#        sv_setpv((SV*)cv$proto) ;
EOF
        }
    }
    else {
	push(@InitFileCode,
	     "        ${newXS}(\"$pname\", XS_$Full_func_name, file$proto);\n");
    }
}

# print initialization routine
print Q<<"EOF";
##ifdef __cplusplus
#extern "C"
##endif
#XS(boot_$Module_cname)
#[[
#    dXSARGS;
#    char* file = __FILE__;
#
EOF

print Q<<"EOF" if $WantVersionChk ;
#    XS_VERSION_BOOTCHECK ;
#
EOF

print Q<<"EOF" if defined $XsubAliases ;
#    {
#        CV * cv ;
#
EOF

print @InitFileCode;

print Q<<"EOF" if defined $XsubAliases ;
#    }
EOF

if (@BootCode)
{
    print "\n    /* Initialisation Section */\n" ;
    print grep (s/$/\n/, @BootCode) ;
    print "\n    /* End of Initialisation Section */\n\n" ;
}

print Q<<"EOF";;
#    ST(0) = &sv_yes;
#    XSRETURN(1);
#]]
EOF

warn("Please specify prototyping behavior for $filename (see perlxs manual)\n") 
    unless $ProtoUsed ;
&Exit;


sub output_init {
    local($type, $num, $init) = @_;
    local($arg) = "ST(" . ($num - 1) . ")";

    eval qq/print " $init\\\n"/;
}

sub Warn
{
    # work out the line number
    my $line_no = $line_no[@line_no - @line -1] ;
 
    print STDERR "@_ in $filename, line $line_no\n" ;
}

sub blurt 
{ 
    Warn @_ ;
    $errors ++ 
}

sub death
{
    Warn @_ ;
    exit 1 ;
}

sub generate_init {
    local($type, $num, $var) = @_;
    local($arg) = "ST(" . ($num - 1) . ")";
    local($argoff) = $num - 1;
    local($ntype);
    local($tk);

    $type = TidyType($type) ;
    blurt("Error: '$type' not in typemap"), return 
	unless defined($type_kind{$type});

    ($ntype = $type) =~ s/\s*\*/Ptr/g;
    ($subtype = $ntype) =~ s/(?:Array)?(?:Ptr)?$//;
    $tk = $type_kind{$type};
    $tk =~ s/OBJ$/REF/ if $func_name =~ /DESTROY$/;
    $type =~ tr/:/_/;
    blurt("Error: No INPUT definition for type '$type' found"), return
        unless defined $input_expr{$tk} ;
    $expr = $input_expr{$tk};
    if ($expr =~ /DO_ARRAY_ELEM/) {
        blurt("Error: '$subtype' not in typemap"), return 
	    unless defined($type_kind{$subtype});
        blurt("Error: No INPUT definition for type '$subtype' found"), return
            unless defined $input_expr{$type_kind{$subtype}} ;
	$subexpr = $input_expr{$type_kind{$subtype}};
	$subexpr =~ s/ntype/subtype/g;
	$subexpr =~ s/\$arg/ST(ix_$var)/g;
	$subexpr =~ s/\n\t/\n\t\t/g;
	$subexpr =~ s/is not of (.*\")/[arg %d] is not of $1, ix_$var + 1/g;
	$subexpr =~ s/\$var/${var}[ix_$var - $argoff]/;
	$expr =~ s/DO_ARRAY_ELEM/$subexpr/;
    }
    if (defined($defaults{$var})) {
	    $expr =~ s/(\t+)/$1    /g;
	    $expr =~ s/        /\t/g;
	    eval qq/print "\\t$var;\\n"/;
	    $deferred .= eval qq/"\\n\\tif (items < $num)\\n\\t    $var = $defaults{$var};\\n\\telse {\\n$expr;\\n\\t}\\n"/;
    } elsif ($expr !~ /^\t\$var =/) {
	    eval qq/print "\\t$var;\\n"/;
	    $deferred .= eval qq/"\\n$expr;\\n"/;
    } else {
	    eval qq/print "$expr;\\n"/;
    }
}

sub generate_output {
    local($type, $num, $var) = @_;
    local($arg) = "ST(" . ($num - ($num != 0)) . ")";
    local($argoff) = $num - 1;
    local($ntype);

    $type = TidyType($type) ;
    if ($type =~ /^array\(([^,]*),(.*)\)/) {
	    print "\tsv_setpvn($arg, (char *)$var, $2 * sizeof($1)), XFree((char *)$var);\n";
    } else {
	    blurt("Error: '$type' not in typemap"), return
		unless defined($type_kind{$type});
            blurt("Error: No OUTPUT definition for type '$type' found"), return
                unless defined $output_expr{$type_kind{$type}} ;
	    ($ntype = $type) =~ s/\s*\*/Ptr/g;
	    $ntype =~ s/\(\)//g;
	    ($subtype = $ntype) =~ s/(?:Array)?(?:Ptr)?$//;
	    $expr = $output_expr{$type_kind{$type}};
	    if ($expr =~ /DO_ARRAY_ELEM/) {
	        blurt("Error: '$subtype' not in typemap"), return
		    unless defined($type_kind{$subtype});
                blurt("Error: No OUTPUT definition for type '$subtype' found"), return
                    unless defined $output_expr{$type_kind{$subtype}} ;
		$subexpr = $output_expr{$type_kind{$subtype}};
		$subexpr =~ s/ntype/subtype/g;
		$subexpr =~ s/\$arg/ST(ix_$var)/g;
		$subexpr =~ s/\$var/${var}[ix_$var]/g;
		$subexpr =~ s/\n\t/\n\t\t/g;
		$expr =~ s/DO_ARRAY_ELEM\n/$subexpr/;
		eval "print qq\a$expr\a";
	    }
	    elsif ($var eq 'RETVAL') {
		if ($expr =~ /^\t\$arg\s*=\s*\$var\s*;/) {
		    eval "print qq\a$expr\a";
		    print "\tif (SvREFCNT(ST(0))) sv_2mortal(ST(0));\n";
		} 
		elsif ($expr =~ /^\t\$arg = /) {
		    eval "print qq\a$expr\a";
		    print "\tsv_2mortal(ST(0));\n";
		}
		else {
		    print "\tST(0) = sv_newmortal();\n";
		    eval "print qq\a$expr\a";
		}
	    }
	    elsif ($arg =~ /^ST\(\d+\)$/) {
		eval "print qq\a$expr\a";
	    }
    }
}

sub map_type {
    my($type) = @_;

    $type =~ tr/:/_/;
    $type =~ s/^array\(([^,]*),(.*)\).*/$1 */s;
    $type;
}


sub Exit {
# If this is VMS, the exit status has meaning to the shell, so we
# use a predictable value (SS$_Normal or SS$_Abort) rather than an
# arbitrary number.
    exit ($Is_VMS ? ($errors ? 44 : 1) : $errors) ;
}