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> Why did Chez and Racket embrace R6RS, a standard widely rejected by the rest of the Scheme community? Why wouldn't they? The usual rationale for rejecting R6

> Why did Chez and Racket embrace R6RS, a standard widely rejected by the rest of the Scheme community? Why wouldn't they? The usual rationale for rejecting R6RS is that it's somehow "too big". But Racket already has a library whose size blows R6RS out of the water. So this rationale is irrelevant in this context. Also, Chez Scheme is an implementation detail. R6RS is only one of many languages that you may use through Racket. And what is this "Scheme community" that rejected R6RS? It's always been my impression that it was rejected by authors of toy implementations. Is there actually any data on what portion of people who use Scheme (as opposed to write another implementation of it) reject R6RS?

bitwize 6y ago
> Why wouldn't they? The usual rationale for rejecting R6RS is that it's somehow "too big". But Racket already has a library whose size blows R6RS out of the water. So this rationale is irrelevant in this context. No one begrudges Racket for having a huge library. The Racket team have obviously had enormous success building large, comprehensive real-world systems. But Racket is an implementation -- not the Scheme standard. The historic value of the Scheme standard is its smallness and ease of implementation -- a small base upon which to build large systems. Large, comprehensive implementations -- such as T -- have been built on top of this small basis for almost as long as there's been an RnRS. R6RS represented a fundamental shift in philosophy for what is Scheme. It de-emphasized the "small language kernel" approach and emphasized a comprehensive, software-engineering approach for building "real world systems". But the Lisp community already has a comprehensive, software-engineering-oriented language, Common Lisp (which borrowed some of its best features, like lexical scoping, from Scheme). So what's the point of building Scheme into a large software-engineering language to compete with Common Lisp? It's a bit hard to fathom today, when most modern programming languages -- excluding ECMAScript but including, for example, Rust -- are defined in terms of a single reference implementation, but there are advantages to keeping the language standard small while allowing implementations to grow to arbitrary size and accrete features. Advantages which Scheme has turned into its own little niche among the family of Lisp programming languages. > And what is this "Scheme community" that rejected R6RS? It's always been my impression that it was rejected by authors of toy implementations. Of course, because Gambit, Chicken, and Gauche -- among others -- are mere toys. A toy implementation that implements all of R5RS is at least possible. You can't build a toy implementation of Common Lisp, Python, or Rust, that covers even a small fraction of the core language. But you can build a Scheme that's nearly or entirely R5RS-compliant in maybe a few thousand lines of C, and from there build out the language to incorporate Python- or Rust-like features. "Toy" Schemes can even be useful in production, as an embedded scripting layer to a larger system.
- cwyers 6y ago
  The reason for Racket and its large library to embrace a large standard is the amount of things that Racket doesn't have to implement itself because it's in the standard already.
  - bitwize 6y ago
    That's not how standards work. The standard just specifies something; you still have to implement it, unless the standard supplies a reference implementation which you can make work with your code. There's a reason why the quasi-standards for extensions to Scheme are called Scheme Requests for Implementation. Neither R6RS nor any other RnRS standard contain a reference implementation, so whether it's in R6RS or not, the Racket developers have to implement it. RnRS standards do tend to have a description of Scheme's formal semantics, and SRFI documents, by convention, contain a reference implementation of the proposed API where possible.

bitwize 6y ago

> Why wouldn't they? The usual rationale for rejecting R6RS is that it's somehow "too big". But Racket already has a library whose size blows R6RS out of the water. So this rationale is irrelevant in this context. No one begrudges Racket for having a huge library. The Racket team have obviously had enormous success building large, comprehensive real-world systems. But Racket is an implementation -- not the Scheme standard. The historic value of the Scheme standard is its smallness and ease of implementation -- a small base upon which to build large systems. Large, comprehensive implementations -- such as T -- have been built on top of this small basis for almost as long as there's been an RnRS. R6RS represented a fundamental shift in philosophy for what is Scheme. It de-emphasized the "small language kernel" approach and emphasized a comprehensive, software-engineering approach for building "real world systems". But the Lisp community already has a comprehensive, software-engineering-oriented language, Common Lisp (which borrowed some of its best features, like lexical scoping, from Scheme). So what's the point of building Scheme into a large software-engineering language to compete with Common Lisp? It's a bit hard to fathom today, when most modern programming languages -- excluding ECMAScript but including, for example, Rust -- are defined in terms of a single reference implementation, but there are advantages to keeping the language standard small while allowing implementations to grow to arbitrary size and accrete features. Advantages which Scheme has turned into its own little niche among the family of Lisp programming languages. > And what is this "Scheme community" that rejected R6RS? It's always been my impression that it was rejected by authors of toy implementations. Of course, because Gambit, Chicken, and Gauche -- among others -- are mere toys. A toy implementation that implements all of R5RS is at least possible. You can't build a toy implementation of Common Lisp, Python, or Rust, that covers even a small fraction of the core language. But you can build a Scheme that's nearly or entirely R5RS-compliant in maybe a few thousand lines of C, and from there build out the language to incorporate Python- or Rust-like features. "Toy" Schemes can even be useful in production, as an embedded scripting layer to a larger system.

cwyers 6y ago
The reason for Racket and its large library to embrace a large standard is the amount of things that Racket doesn't have to implement itself because it's in the standard already.
- bitwize 6y ago
  That's not how standards work. The standard just specifies something; you still have to implement it, unless the standard supplies a reference implementation which you can make work with your code. There's a reason why the quasi-standards for extensions to Scheme are called Scheme Requests for Implementation. Neither R6RS nor any other RnRS standard contain a reference implementation, so whether it's in R6RS or not, the Racket developers have to implement it. RnRS standards do tend to have a description of Scheme's formal semantics, and SRFI documents, by convention, contain a reference implementation of the proposed API where possible.