4 ms·

And now Racket, which used to be a Scheme, doesn't call itself a Scheme anymore. In fact it describes itself on its web site as "The best of Scheme and Lisp."

by mbrock 8y ago

kazinator 8y ago
That is correct; you can't be Scheme if you just have the best of it, and not the rest of it. E.g. Racket doesn't have set-car! and set-cdr! so RnRS-conforming Scheme programs which rely on these won't work.
- mbrock 8y ago
  On the other hand some weirdos try to claim that Python is “a Lisp”...
- soegaard 8y ago
  Racket does support mutable pairs. http://docs.racket-lang.org/reference/mpairs.html?q=mcons#%28part._.Mutable_.Pair_.Constructors_and_.Selectors%29 http://docs.racket-lang.org/reference/mpairs.html?q=mcons#%2...
  - kazinator 8y ago
    That's nice, but in Scheme, all pairs constructed by any code anywhere are mutable, and structure made out of mutable pairs can be passed into any library function. An object notation like (a b c) read from a stream gives you a mutable object. It's a significant language difference that can't be papered over with a data type and handful of functions.
    - soegaard 8y ago
      That's a different concern. Racket supports both immutable and mutable cons cells. Convenient or not - you decide. Oh, been watching too much YouTube. In both Racket and Scheme it is usually a good idea to program in a functional style - i.e. not to mutate pairs. The compiler and runtime system can in some situations handle immutable pairs more efficiently than mutable pairs. So if mutable pairs are seldomly used, it makes sense to make immutable pairs the default. The rationale why Racket made the shift is described here: http://blog.racket-lang.org/2007/11/getting-rid-of-set-car-and-set-cdr.html http://blog.racket-lang.org/2007/11/getting-rid-of-set-car-a... In short: the Racket community sees the immutable default as a plus.

And now Racket, which used to be a Scheme, doesn't call itself a Scheme anymore. In fact it describes itself on its web site as "The best of Scheme and Lisp."

by mbrock 8y ago

And now Racket, which used to be a Scheme, doesn't call itself a Scheme anymore. In fact it describes itself on its web site as "The best of Scheme and Lisp."

kazinator 8y ago

That is correct; you can't be Scheme if you just have the best of it, and not the rest of it. E.g. Racket doesn't have set-car! and set-cdr! so RnRS-conforming Scheme programs which rely on these won't work.

mbrock 8y ago
On the other hand some weirdos try to claim that Python is “a Lisp”...
soegaard 8y ago
Racket does support mutable pairs. http://docs.racket-lang.org/reference/mpairs.html?q=mcons#%28part._.Mutable_.Pair_.Constructors_and_.Selectors%29 http://docs.racket-lang.org/reference/mpairs.html?q=mcons#%2...
- kazinator 8y ago
  That's nice, but in Scheme, all pairs constructed by any code anywhere are mutable, and structure made out of mutable pairs can be passed into any library function. An object notation like (a b c) read from a stream gives you a mutable object. It's a significant language difference that can't be papered over with a data type and handful of functions.
  - soegaard 8y ago
    That's a different concern. Racket supports both immutable and mutable cons cells. Convenient or not - you decide. Oh, been watching too much YouTube. In both Racket and Scheme it is usually a good idea to program in a functional style - i.e. not to mutate pairs. The compiler and runtime system can in some situations handle immutable pairs more efficiently than mutable pairs. So if mutable pairs are seldomly used, it makes sense to make immutable pairs the default. The rationale why Racket made the shift is described here: http://blog.racket-lang.org/2007/11/getting-rid-of-set-car-and-set-cdr.html http://blog.racket-lang.org/2007/11/getting-rid-of-set-car-a... In short: the Racket community sees the immutable default as a plus.