# RECURSIVE #includes DURING A RECURSIVE DESCENT

use Parse::RecDescent;

sub loadfile($)
{
    open FILE, $_[0]  or die "Couldn't find included file: $_[0]\n";
    my $contents = <FILE>;
    close FILE;
    return $contents;
}

%macro = ();

sub demacro($)
{
    my $text = shift;
    while (($macro,$defn) = each %macro )
    {
        $text =~ s/$macro/$defn/;
    }
    return $text;
}

$grammar =
q{
    file     : line(s)

    line     : include
         | macrodef
         | linedir
            { $thisline = $item[1]; }
         | codeline
            { print "found: [$item[1]] at $thisline\n" }

    include     : '#include' filename
            {
              print "pre: [$text] at $thisline\n";
              $text = ::loadfile($item[-1]) . $text;
              Parse::RecDescent::LineCounter::resync $thisline;
              print "post: [$text] at $thisline\n";
            }

    filename : '"' m#[a-z0-9_./-]+#i '"'
            { $return = $item[-2] }
         | '<' m#[a-z0-9_./-]+#i '>'
            { $return = $item[-2] }

    macrodef : '#define' /[a-z]\w*/i /.*/
            { $::macro{$item[-2]} = $item[-1] }

    linedir:   '#line' /\d+/

    codeline : /.*\n/
            { $return = ::demacro($item[-1]); }

};

$parse = new Parse::RecDescent ($grammar);

undef $/;

$reinput = $input = <>;

$parse->file($input) or die "Bad file! No biscuit!\n";

$parse->file($reinput) or die "Bad file! No biscuit!\n";