[dan-robertson]

Both C++ and Common Lisp suffer a huge accumulation of historical baggage. It is this that makes the languages problematic, not being multi-paradigm. Common Lisp has first/rest as well as car/cdr. It has streams and numbers and the functions on them seem generic but aren’t (always) generic functions. It still has rplca despite (setf car) being a valid function name.

[vnorilo]

Sure; but "historical baggage" is a function of multi-paradigm and outliving multiple generations of computer architecture. I would not view baggage as necessarily problematic. What makes C++ problematic is that template metaprogramming evolved in a very ad hoc way, and now we need to backwards compatible all of it.

[dan-robertson]

My claim is that these multi-paradigm languages may be better thought of as a core plus some paradigm-specific sublanguages, all jammed into the same syntax and glued together in random places. A better multi-paradigm language could avoid having separate parts that poorly work together. The thing that the comment I first replied to called ‘multi-paradigm’ is I think really the bad glue job like a plate that was smashed, glued together, smashed, and then glued together a second time. I don’t think it is an essential quality of multi-paradigm languages. For example Raku (fka perl6) fits different paradigms together more smoothly, and Julia can be used in a procedural or functional way as well as a more object-oriented way (though Julia’s objects tend not to contain as much state as a typical object-oriented language)