[ruby.parslet] Parslet equivalent of & and ` (the back-tick)

[Frank]

Hi,
   What are the parslet equivalents of '&' and '`' (the back-tick)?  For
Anyone unfamiliar with these operators, the & indicates the element to the
right must follow (but the marked element itself does not absorb anything)
while the back-tick means the parser is not to include the matched text in
the parse tree; the parser must still match the text for success pattern
matching; it just never appears in the final parse tree.

Thanks in advance!