I'm not super familiar with Raku, but if RakuAST is what you had in mind it looks a bit different:

    use experimental :rakuast;
    
    my $ast = RakuAST::Call::Name.new(
      name => RakuAST::Name.from-identifier("say"),
      args => RakuAST::ArgList.new(
        RakuAST::StrLiteral.new("Hello world")
      )
    );

Looks more like "low-level programming an AST" (which I believe other languages offer as well), rather than using a bidirectional transform. I don't know how you'd get Raku code back out, for example.

Edit: I should have looked deeper, `DEPARSE` does exactly this:

https://docs.raku.org/type/RakuAST

Neat!

It also goes from source code to AST:

  $ raku -e 'say Q|say "Hello World!"|.AST'
  RakuAST::StatementList.new(
    RakuAST::Statement::Expression.new(
      expression => RakuAST::Call::Name::WithoutParentheses.new(
        name => RakuAST::Name.from-identifier("say"),
        args => RakuAST::ArgList.new(
          RakuAST::QuotedString.new(
            segments   => (
              RakuAST::StrLiteral.new("Hello World!"),
            )
          )
        )
      )
    )
  )

thanks, all.