I'm not very familiar with Camlp4. I tried skimming the tutorial to see if some of the big benefits of Perl 6's syntactic extension are there, but couldn't tell

I'm not very familiar with Camlp4. I tried skimming the tutorial to see if some of the big benefits of Perl 6's syntactic extension are there, but couldn't tell. Are Camlp4 extensions lexical? Can you load some syntactic extension within a single function and have it apply within only that function's lexical scope? If I understand Camlp4 correctly, it's essentially a pre-processor. It's a very powerful pre-processor, perhaps, but you'd probably have to work very deep magic to be able to replace the Ocaml parser for a lexical scope. This is not yet implemented, but eventually you'll be able to do 'supersede slang MAIN { ... }' and rewrite the grammar the current lexical scope. How easy is it to use Camlp4 extensions from OCaml programs? In Perl 6, it's a simple matter of "use SomeModule;". Here's the code of a module to provide a factorial operator. module Factorial; multi sub postfix:<!>(Mu $n) is export { [*] 1..$n; } And an example of using it: use Factorial; say 5!; # outputs 120 This is actually essentially how many of the built-in operators are provided in Rakudo. The ones that aren't provided in this way are the ones like || and && with short-circuiting semantics which need to be evaluated specially and the ones that are better implemented in PIR. I'm afraid I don't have any examples of more extensive grammar modifications, as Rakudo doesn't have much support for them yet. More accurately, it doesn't have support for adding them in mid-parse yet; it's fairly simple to create a new grammar class deriving from Rakudo's Perl6::Grammar with a few modifications and parse files with it.