Check out this document to see how the Fil-C ports of Python and Perl and so on work:

https://github.com/mbrock/filnix/blob/main/ports/analysis.md

This is still within the userspace application realm but it's good to know that Fil-C does have explicit capability-preserving operations (`zxorptr`, `zretagptr`, etc) to do e.g. pointer tagging, and special support for mapping pointers to integer table indices and back (`zptrtable`, etc).