I've used fset and cl21. The problem is that once you start using those you no longer are able to use libraries. Data structures have to be built into core.
The common lisp community has rejected reader macros for interop reasons the last time I checked (in the case of cl21)
Even the docs for fset doesn't show the use of data literals. it does things like (set) and (isetq s2 (set 'c 1 "foo" 'a 'c))
This pretty much proves my point. it's not fun typing (set 'c 1 "foo" 'a 'c) instead of #{'c 1 "foo" 'a 'c}. It's also not possible to put those on the wire (easily) for communication between common lisp processes. Breaking the whole point of homoiconicity.
The common lisp community has rejected reader macros for interop reasons the last time I checked (in the case of cl21)
Even the docs for fset doesn't show the use of data literals. it does things like (set) and (isetq s2 (set 'c 1 "foo" 'a 'c))
This pretty much proves my point. it's not fun typing (set 'c 1 "foo" 'a 'c) instead of #{'c 1 "foo" 'a 'c}. It's also not possible to put those on the wire (easily) for communication between common lisp processes. Breaking the whole point of homoiconicity.