4 ms·

Correct me if I'm wrong, but Lisp-2 vs. Lisp-1 has nothing to do with hygiene, it just splits Scheme's single problem (lexically binding values in macros) into

by tines 6y ago

Correct me if I'm wrong, but Lisp-2 vs. Lisp-1 has nothing to do with hygiene, it just splits Scheme's single problem (lexically binding values in macros) into two problems (lexically binding values in macros, and lexically binding functions in macros). The real problem, which Naggum includes, is the lack of GENSYM (if scheme indeed lacks it), and lack of first class symbols, as he mentioned.

ska 6y ago
It's somewhat orthogonal, yes, but a lisp-1 just has more ways to run into the name collision.
deckard1 6y ago
> it just splits Scheme's single problem (lexically binding values in macros) into two problems (lexically binding values in macros, and lexically binding functions in macros). Bingo. Lisp-2 and GENSYM are attempting to solve the same issue in two different use cases. And, if I may add, GENSYM looks a bit lazy and half-assed next to the scortch-the-earth multiple namespaces of Lisp-2. It's like they blew up Lisp with dynamite and then sat down and said "whatever" when the same problem appears in macros. > The real problem, which Naggum includes, is the lack of GENSYM Guile Scheme has both GENSYM and DEFMACRO (unhygienic). I think quite a few Scheme systems err on the side of practical concerns. But that doesn't erase that fact that GENSYM is an ugly hack to get macros to work.
- varjag 6y ago
  > Lisp-2 and GENSYM are attempting to solve the same issue in two different use cases. Now this is… post-hoc, Lisp-2 is the original form of LISP and predates the concepts of macros. > And, if I may add, GENSYM looks a bit lazy and half-assed next to the scortch-the-earth multiple namespaces of Lisp-2. I would agree. However in reality we have a system that is half-assed vs a system that nobody likes to use.
  - lispm 6y ago
    > predates the concepts of macros Though LISP macros are quite old, from around 1962...
bjoli 6y ago
Most schemes have a gensym as a part of their lower level macro facilities. It is a part of r6rs (which at least has generate-temporaries, I don't know if gensym is actually standard. All schemes I have used have it).

by tines 6y ago

ska 6y ago

It's somewhat orthogonal, yes, but a lisp-1 just has more ways to run into the name collision.

deckard1 6y ago

> it just splits Scheme's single problem (lexically binding values in macros) into two problems (lexically binding values in macros, and lexically binding functions in macros). Bingo. Lisp-2 and GENSYM are attempting to solve the same issue in two different use cases. And, if I may add, GENSYM looks a bit lazy and half-assed next to the scortch-the-earth multiple namespaces of Lisp-2. It's like they blew up Lisp with dynamite and then sat down and said "whatever" when the same problem appears in macros. > The real problem, which Naggum includes, is the lack of GENSYM Guile Scheme has both GENSYM and DEFMACRO (unhygienic). I think quite a few Scheme systems err on the side of practical concerns. But that doesn't erase that fact that GENSYM is an ugly hack to get macros to work.

varjag 6y ago
> Lisp-2 and GENSYM are attempting to solve the same issue in two different use cases. Now this is… post-hoc, Lisp-2 is the original form of LISP and predates the concepts of macros. > And, if I may add, GENSYM looks a bit lazy and half-assed next to the scortch-the-earth multiple namespaces of Lisp-2. I would agree. However in reality we have a system that is half-assed vs a system that nobody likes to use.
- lispm 6y ago
  > predates the concepts of macros Though LISP macros are quite old, from around 1962...

bjoli 6y ago

Most schemes have a gensym as a part of their lower level macro facilities. It is a part of r6rs (which at least has generate-temporaries, I don't know if gensym is actually standard. All schemes I have used have it).