/IronPython_Main/Runtime/Tests/LinqDlrTests/testenv/perl/lib/Fatal.pm

package Fatal;



use 5.005_64;

use Carp;

use strict;

our($AUTOLOAD, $Debug, $VERSION);



$VERSION = 1.02;



$Debug = 0 unless defined $Debug;



sub import {

    my $self = shift(@_);

    my($sym, $pkg);

    my $void = 0;

    $pkg = (caller)[0];

    foreach $sym (@_) {

	if ($sym eq ":void") {

	    $void = 1;

	}

	else {

	    &_make_fatal($sym, $pkg, $void);

	}

    }

};



sub AUTOLOAD {

    my $cmd = $AUTOLOAD;

    $cmd =~ s/.*:://;

    &_make_fatal($cmd, (caller)[0]);

    goto &$AUTOLOAD;

}



sub fill_protos {

  my $proto = shift;

  my ($n, $isref, @out, @out1, $seen_semi) = -1;

  while ($proto =~ /\S/) {

    $n++;

    push(@out1,[$n,@out]) if $seen_semi;

    push(@out, $1 . "{\$_[$n]}"), next if $proto =~ s/^\s*\\([\@%\$\&])//;

    push(@out, "\$_[$n]"), next if $proto =~ s/^\s*([*\$&])//;

    push(@out, "\@_[$n..\$#_]"), last if $proto =~ s/^\s*(;\s*)?\@//;

    $seen_semi = 1, $n--, next if $proto =~ s/^\s*;//; # XXXX ????

    die "Unknown prototype letters: \"$proto\"";

  }

  push(@out1,[$n+1,@out]);

  @out1;

}



sub write_invocation {

  my ($core, $call, $name, $void, @argvs) = @_;

  if (@argvs == 1) {		# No optional arguments

    my @argv = @{$argvs[0]};

    shift @argv;

    return "\t" . one_invocation($core, $call, $name, $void, @argv) . ";\n";

  } else {

    my $else = "\t";

    my (@out, @argv, $n);

    while (@argvs) {

      @argv = @{shift @argvs};

      $n = shift @argv;

      push @out, "$ {else}if (\@_ == $n) {\n";

      $else = "\t} els";

      push @out, 

          "\t\treturn " . one_invocation($core, $call, $name, $void, @argv) . ";\n";

    }

    push @out, <<EOC;

	}

	die "$name(\@_): Do not expect to get ", scalar \@_, " arguments";

EOC

    return join '', @out;

  }

}



sub one_invocation {

  my ($core, $call, $name, $void, @argv) = @_;

  local $" = ', ';

  if ($void) { 

    return qq/(defined wantarray)?$call(@argv):

              $call(@argv) || croak "Can't $name(\@_)/ . 

           ($core ? ': $!' : ', \$! is \"$!\"') . '"'

  } else {

    return qq{$call(@argv) || croak "Can't $name(\@_)} . 

           ($core ? ': $!' : ', \$! is \"$!\"') . '"';

  }

}



sub _make_fatal {

    my($sub, $pkg, $void) = @_;

    my($name, $code, $sref, $real_proto, $proto, $core, $call);

    my $ini = $sub;



    $sub = "${pkg}::$sub" unless $sub =~ /::/;

    $name = $sub;

    $name =~ s/.*::// or $name =~ s/^&//;

    print "# _make_fatal: sub=$sub pkg=$pkg name=$name void=$void\n" if $Debug;

    croak "Bad subroutine name for Fatal: $name" unless $name =~ /^\w+$/;

    if (defined(&$sub)) {	# user subroutine

	$sref = \&$sub;

	$proto = prototype $sref;

	$call = '&$sref';

    } elsif ($sub eq $ini) {	# Stray user subroutine

	die "$sub is not a Perl subroutine" 

    } else {			# CORE subroutine

        $proto = eval { prototype "CORE::$name" };

	die "$name is neither a builtin, nor a Perl subroutine" 

	  if $@;

	die "Cannot make a non-overridable builtin fatal"

	  if not defined $proto;

	$core = 1;

	$call = "CORE::$name";

    }

    if (defined $proto) {

      $real_proto = " ($proto)";

    } else {

      $real_proto = '';

      $proto = '@';

    }

    $code = <<EOS;

sub$real_proto {

	local(\$", \$!) = (', ', 0);

EOS

    my @protos = fill_protos($proto);

    $code .= write_invocation($core, $call, $name, $void, @protos);

    $code .= "}\n";

    print $code if $Debug;

    {

      no strict 'refs'; # to avoid: Can't use string (...) as a symbol ref ...

      $code = eval("package $pkg; use Carp; $code");

      die if $@;

      no warnings;   # to avoid: Subroutine foo redefined ...

      *{$sub} = $code;

    }

}



1;



__END__



=head1 NAME



Fatal - replace functions with equivalents which succeed or die



=head1 SYNOPSIS



    use Fatal qw(open close);



    sub juggle { . . . }

    import Fatal 'juggle';



=head1 DESCRIPTION



C<Fatal> provides a way to conveniently replace functions which normally

return a false value when they fail with equivalents which raise exceptions

if they are not successful.  This lets you use these functions without

having to test their return values explicitly on each call.  Exceptions

can be caught using C<eval{}>.  See L<perlfunc> and L<perlvar> for details.



The do-or-die equivalents are set up simply by calling Fatal's

C<import> routine, passing it the names of the functions to be

replaced.  You may wrap both user-defined functions and overridable

CORE operators (except C<exec>, C<system> which cannot be expressed

via prototypes) in this way.



If the symbol C<:void> appears in the import list, then functions

named later in that import list raise an exception only when

these are called in void context--that is, when their return

values are ignored.  For example



	use Fatal qw/:void open close/;



	# properly checked, so no exception raised on error

	if(open(FH, "< /bogotic") {

		warn "bogo file, dude: $!";

	}



	# not checked, so error raises an exception

	close FH;



=head1 AUTHOR



Lionel.Cons@cern.ch



prototype updates by Ilya Zakharevich ilya@math.ohio-state.edu



=cut