VIM: Perl interface, passing a variable to Perl and reading a vim variable from Perl

I use a Perl(loader.vim) script to load VIM modules: (.vimrc) source /whatever/loader.vim

loader.vim:

function! LoadBundles()
perl  HERE

while(</root/.vim/bundle/*/plugin/*&开发者_StackOverflowgt;) {
  my ($path, $fname) =($_ =~ m|^(.+/)(.+?)$|);
  #VIM::Msg("$path $fname\n");
  VIM::DoCommand("set runtimepath=$path");
  VIM::DoCommand("runtime! $fname");
}
HERE
endfunction

call LoadBundles()

I'd like to do something like LoadBundles('/path/to/bundledir') but to do this I need to be able to read a variable from within Perl eg:

function! LoadBundles(path)
  let var = a:path
perl HERE
print "$var\n";

How do I do this???

I'd also like to save the runtimepath within perl HERE and then restore it. How do I read runtimepath from within perl HERE?

Here's how you can get at the "runtimepath" option from embedded Perl:

perl VIM::Msg( VIM::Eval('&runtimepath') )

Do the following to get more from the docs:

:help if_perl.txt

Then search for "VIM::Eval". So try:

function! AnExample(arg)
perl << EOF
    VIM::Msg( VIM::Eval('a:arg') )
EOF
endfunction

And then to test:

:so %
:call AnExample("hello")