Earlier quoted context omitted.
I think most schemes also don't have reader macros. How often do you actually use them in CL? I feel reader macros have the problem that it modifies/extend the foundational syntax. And that can become overloaded really quickly. Normal macros can change evaluation semantics, but not the fundamental syntax. Which makes it easier to navigate and understand in general. Also, reader macros are pretty hard to write in comp…
> I think most schemes also don't have reader macros. Scheme even has a fixed syntax in the RnRS reports. Lisp does not have that. > Also, reader macros are pretty hard to write in comparison. Not really. One just reads things from a stream and returns an s-expression. > I feel reader macros have the problem that it modifies/extend the foundational syntax That's a feature. The main purpose of user-written reader macr…
Could you link to the RnRS in question? I'm curious.
> Not really. One just reads things from a stream and returns an s-expression.
I feel like if I agree to this, I also agree that pre-processors are easy to write and use. And that undermines the innovation and superiority of syntactic macros introduced by Lisp.
> The main purpose of user-written reader macros is to extend S-expressions to support literal syntax of new user-defined data types.
This is possible in Clojure as well. You can extend the language with new data literals. But they must begin with # + char(s) and respect the existing reader semantics, as they are processed as a syntactic macro, and not a lexical one. So you could add #queue[1 2 3] for example. But you couldn't add |1 2 3|
> On my Lisp Machine it was actually useful.
If only they'd still make those, and had improved its performance.