{
        my $missing = grep { ! -e $_ } @inputFiles ;

        if ($missing)
        {
            $Error = "$missing input files do not exist";
            return undef ;
        }
    }

    $self->{InputFiles} = \@inputFiles ;

    $self->_getFiles()
        or return undef ;

    return $self;
}

sub _retError
{
    my $string = shift ;
    $Error = "$string in input fileglob" ;
    return undef ;
}

sub _unmatched
{
    my $delimeter = shift ;

    _retError("Unmatched $delimeter");
    return undef ;
}

sub _parseBit
{
    my $self = shift ;

    my $string = shift ;

    my $out = '';
    my $depth = 0 ;

    while ($string =~ s/(.*?)$noPreBS(,|$matchMetaRE)//)
    {
        $out .= quotemeta($1) ;
        $out .= $mapping{$2} if defined $mapping{$2};

        ++ $self->{WildCount} if $wildCount{$2} ;

        if ($2 eq ',')
        { 
            return _unmatched "("
                if $depth ;
            
            $out .= '|';
        }
        elsif ($2 eq '(')
        { 
            ++ $depth ;
        }
        elsif ($2 eq ')')
        { 
            return _unmatched ")"
                if ! $depth ;

            -- $depth ;
        }
        elsif ($2 eq '[')
        {
            # TODO -- quotemeta & check no '/'
            # TODO -- check for \]  & other \ within the []
            $string =~ s#(.*?\])##
                or return _unmatched "[" ;
            $out .= "$1)" ;
        }
        elsif ($2 eq ']')
        {
            return _unmatched "]" ;
        }
        elsif ($2 eq '{' || $2 eq '}')
        {
            return _retError "Nested {} not allowed" ;
        }
    }

    $out .= quotemeta $string;

    return _unmatched "("
        if $depth ;

    return $out ;
}

sub _parseInputGlob
{
    my $self = shift ;

    my $string = $self->{InputGlob} ;
    my $inGlob = '';