my $s = "($big_string)"; 
list_extr(\$s)
##</code><code>##

list_extr(\( "(" . $big_string . ")" ));
##</code><code>##

my $ttt = "(" . $big_string . ")";
list_extr(\$ttt);

##</code><code>##

 
# \G(?:\s|#.*$)* -- means start from last position \G, 
#                   skip spaces and comments # till the 
#                   end of line
# ([[:alpha:]](?:_?[[:alnum:]])*) -- my identifier 
#           restrictions; start with letter, then 
#           letters, underscores, digits; but 
#           two underscores in a row not allowed, 
#           underscore at the end not allowed

sub list_extr {
        my ($a) = @_;
        ref $a eq 'SCALAR' or croak "wrong ref";
        my @l;
        $$a =~ /\G(?:\s|#.*$)*\(/mgc or croak "parse err";
        while ($$a =~ /\G(?:\s|#.*$)*([[:alpha:]](?:_?[[:alnum:]])*)(?:\s|#.*$)*/mgc) {
                push @l, {'name' => $1, 'parm' => parm_extr($a)};
        }
        $$a =~ /\G(?:\s|#.*$)*\)(?:\s|#.*$)*/mgc or croak "parse err";
        return \@l;
}

sub parm_extr {
        my ($a) = @_;
        ref $a eq 'SCALAR' or croak "wrong ref";
        my %p;
        $$a =~ /\G(?:\s|#.*$)*\(/mgc or croak "parse err";
        while ($$a =~ /\G(?:\s|#.*$)*([[:alpha:]](?:_?[[:alnum:]])*)(?:\s|#.*$)*/mgc) {
                my $n = $1;
                if ($$a =~ /\G([[:alpha:]](?:_?[[:alnum:]])*|"(?:[^\\"[:cntrl:]]+|\\[\\"nt])*")/mgc) {
                        $p{$n} = $1;
                } elsif ($$a =~ /\G(?=[-+.\d])/mgc) {
                        $p{$n} = numb_extr($a);
                } elsif ($$a =~ /\G(?=\()/mgc) {
                        $p{$n} = parm_extr($a);
                } else {
                        croak "parse err"; 
                }
        }
        $$a =~ /\G(?:\s|#.*$)*\)(?:\s|#.*$)*/mgc or croak "parse err";
        return \%p;
}

sub numb_extr {
        my ($a) = @_;
        ref $a eq 'SCALAR' or croak "wrong ref";
        $$a =~ /\G(?:\s|#.*$)*([-+]?\d*(\.\d*)?)/mgc or croak "parse err";
        my $n = $1;
        $n eq '0.0' and return 0;
        $n =~ /\A[-+](?!0.0\z)(?=[1-9]|0\.)\d+\.\d+(?<=[.\d][1-9]|\.0)\z/ or croak "parse err"; 
        length $n <= 15 + 2 or croak "numb too long"; 
        $n = 0 + $n;
        #        1234567890.12345
        abs $n > 99999999999999.9 and croak "numb out of range"; 
        return 0 + $n;
}