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Chez Scheme is now free

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Re: Chez Scheme is now free

#71

Post by brudgers »

jordigh wrote: post #32
sheepleherd wrote: post #29

For people interested in the legalities of licenses, it's released under the Apache License 2.0 which is a "free software" opensource license that is compatible when combined with GPL3, but not with GPL 1 or 2. the Apache 2.0 license includes not just copyright but patent licensing, so the software will contain no hidden patent restrictions for patents owned by the creators and contributors.

Why did you quote free software but not opensource? I am curious to know what the difference in your writing intended to convey.

I think a charitable reading would be that it was intended to convey something other than offense.

Re: Chez Scheme is now free

#72

Post by davexunit »

dman wrote: post #62
chubot wrote: post #50

Earlier quoted context omitted.

I might not be getting a reference here, but FWIW, I had a recent experience with Scheme that was interesting. I did SICP nearly 19 years ago as a freshman, in 1997. And then a few months ago, I ported the metacircular-evaluator -- the "crown" of the course -- to femtolisp (the Lisp implementation underlying Julia). My thoughts were: 1) It sure is awkward to represent struct fields 1 2 3 as (cdr struct), (cadr struct…

Schemes minimalism and elegance makes it a great first language (in my opinion). Plus you can explore multiple programming paradigms - functional, imperative, object oriented. There are legitimate reasons why scheme isnt a very practical language, but its a good first language imo.

>There are legitimate reasons why scheme isnt a very practical language

The operating system I currently run uses a Scheme program as its init system and a Scheme program as its package manager. Scheme is a practical language.

Re: Chez Scheme is now free

#74

Post by jordigh »

brudgers wrote: post #71
jordigh wrote: post #32

Earlier quoted context omitted.

Why did you quote free software but not opensource? I am curious to know what the difference in your writing intended to convey.

I think a charitable reading would be that it was intended to convey something other than offense.

Of course. I don't think anyone is offended. But what was the intended meaning? Can you figure it out?

Re: Chez Scheme is now free

#75

Post by kmill »

chubot wrote: post #50
dman wrote: post #41

Earlier quoted context omitted.

I thought scheme was like the beatles - people universally only had good things to say about it.

I might not be getting a reference here, but FWIW, I had a recent experience with Scheme that was interesting. I did SICP nearly 19 years ago as a freshman, in 1997. And then a few months ago, I ported the metacircular-evaluator -- the "crown" of the course -- to femtolisp (the Lisp implementation underlying Julia). My thoughts were: 1) It sure is awkward to represent struct fields 1 2 3 as (cdr struct), (cadr struct…

Is the fundamental issue in #2 that you don't like the syntax? or that Scheme has mutation?

It's interesting looking back on the history of Scheme. Probably because of the order of presentation of SICP, along with hearsay, people seem to get an impression of Scheme being all about functional programming (and if it's because functions are values you can pass around... well even Algol and Pascal could do that). It's true the original paper was called "Scheme: an interpreter for the extended lambda calculus" [1], but the big idea was that if variables were bound lexically, and if the environment structures used to close the variables were mutable, then you would have something like the actor model -- functions could have state and respond to messages. As they admit in the abstract, the purpose was to demonstrate the core interpreter for implementations of contemporary AI systems. The chapter on register machines in SICP is just an elaboration of their methods in this paper.

[1] http://repository.readscheme.org/ftp/papers/ai-lab-pubs/AIM-...

Something about porting a metacircular evaluator seems odd to me. Not that it's a bad exercise -- it's a good one. But rather, that it's no longer a _metacircular_ evaluator. The progression of the book is 1) abstracting processes and names with procedures 2) abstracting data representation 3) abstracting interface as a module, along with the theory and practice of mutation 4) abstracting semantics with interpreters (programs which take programs as data). The proof that 4 is a thing is by implementing an interpreter for the language in the language and then extending the interpreter in various ways. Even procedure calls are implemented by calling a procedure in the host language. (All I'm saying is that you exercised the metalinguistic abstraction by writing a scheme interpreter in femtolisp. Metacircularity in itself is not much more than an interesting phenomenon to demonstrate.)

(P.S. The language in SICP is not the Scheme which was later standardized, say R5RS + SRFIs. Mutation of lexical closures didn't change. You can't really (cleanly) get away from that until you invent something like a monad to model state.)

Re: Chez Scheme is now free

#76

Post by kmill »

davexunit wrote: post #72
dman wrote: post #62

Earlier quoted context omitted.

Schemes minimalism and elegance makes it a great first language (in my opinion). Plus you can explore multiple programming paradigms - functional, imperative, object oriented. There are legitimate reasons why scheme isnt a very practical language, but its a good first language imo.

>There are legitimate reasons why scheme isnt a very practical language The operating system I currently run uses a Scheme program as its init system and a Scheme program as its package manager. Scheme is a practical language.

To be fair to perception, that Scheme (Guile, I'd imagine) isn't exactly the subset of MIT-Scheme used in SICP.

Re: Chez Scheme is now free

#77

Post by chubot »

davexunit wrote: post #69
chubot wrote: post #64

Earlier quoted context omitted.

OK, point taken about #1. It is valuable to have the basic axioms and then separate syntactic sugar. But #2 and #3 are what I would call bootstrapping problems... in other words, there is a reason that C is the foundation of computing rather than Lisp. I don't think anybody really thinks otherwise anymore. But for example, set-cdr! is not in the lambda calculus, and you need it even for basic things. Likewise, Scheme…

>there is a reason that C is the foundation of computing rather than Lisp. I don't think anybody really thinks otherwise anymore. C is not the foundation of computing. Why would you say this? >Likewise, Scheme implementations have mutable hash tables, but they're written in C and not Scheme. A native code compiler written in Scheme would have its hash table implementation also written in Scheme. >I don't know how you…

C is the foundation of computing in the sense that essentially every programming language and operating system is written in C or C++, and those are the tools that enable every other piece of software. More precisely, I would say that C is the foundation of software; it's how we stopped throwing out our programs when we changed computers. The first portable operating system kernels were written in C.

I guess I could have been more precise and said that the lambda calculus (rather than Scheme/Lisp) is not the foundation of computing. It seems like there are people who still think this; see my recent response here:

https://news.ycombinator.com/item?id=11412392

You could say Lisp and Scheme are proof of that. To actually be bootstrapped, they had to add all this other stuff like vectors and hash tables. I don't know the details of how well those are axiomatized. Paul Graham's Arc tried to a little further down, i.e. unifying functions and macros, defining numbers in terms of lists a la Peano arithmetic, etc., but I'm not sure how far that effort went.

I mentioned all my experience with Lisp... doing SICP 19 years ago, and then coming back to it. As I said, I think it's outstanding research, but if you are trying to build an entire computing universe out of it, that's folly. Good luck. It's just not powerful enough -- once you add all the stuff you actually need, you're not far from the complexity of C.

Re: Chez Scheme is now free

#78

Post by chubot »

davexunit wrote: post #72
dman wrote: post #62

Earlier quoted context omitted.

Schemes minimalism and elegance makes it a great first language (in my opinion). Plus you can explore multiple programming paradigms - functional, imperative, object oriented. There are legitimate reasons why scheme isnt a very practical language, but its a good first language imo.

>There are legitimate reasons why scheme isnt a very practical language The operating system I currently run uses a Scheme program as its init system and a Scheme program as its package manager. Scheme is a practical language.

What operating system is it? Is the Scheme written in C or assembly language?

Re: Chez Scheme is now free

#79

Post by coldtea »

davexunit wrote: post #69
chubot wrote: post #64

Earlier quoted context omitted.

OK, point taken about #1. It is valuable to have the basic axioms and then separate syntactic sugar. But #2 and #3 are what I would call bootstrapping problems... in other words, there is a reason that C is the foundation of computing rather than Lisp. I don't think anybody really thinks otherwise anymore. But for example, set-cdr! is not in the lambda calculus, and you need it even for basic things. Likewise, Scheme…

>there is a reason that C is the foundation of computing rather than Lisp. I don't think anybody really thinks otherwise anymore. C is not the foundation of computing. Why would you say this? >Likewise, Scheme implementations have mutable hash tables, but they're written in C and not Scheme. A native code compiler written in Scheme would have its hash table implementation also written in Scheme. >I don't know how you…

>C is not the foundation of computing. Why would you say this?

Because all the popular OSes, drivers, userlands, servers, GUI libraries, and compilers/languages are 99% written in C (or C++ which is close enough).

Re: Chez Scheme is now free

#80

Post by chubot »

kmill wrote: post #75
chubot wrote: post #50

Earlier quoted context omitted.

I might not be getting a reference here, but FWIW, I had a recent experience with Scheme that was interesting. I did SICP nearly 19 years ago as a freshman, in 1997. And then a few months ago, I ported the metacircular-evaluator -- the "crown" of the course -- to femtolisp (the Lisp implementation underlying Julia). My thoughts were: 1) It sure is awkward to represent struct fields 1 2 3 as (cdr struct), (cadr struct…

Is the fundamental issue in #2 that you don't like the syntax? or that Scheme has mutation? It's interesting looking back on the history of Scheme. Probably because of the order of presentation of SICP, along with hearsay, people seem to get an impression of Scheme being all about functional programming (and if it's because functions are values you can pass around... well even Algol and Pascal could do that). It's tr…

It's both... I feel like Scheme is oversold as axiomatic mathematics. You have to add all this other stuff to it to make anything useful, in particular mutation and mutable data structures. Even toy programs like the metacircular evaluator SICP need this!

And yes, I've been programming a lot in the intervening 19 years, and doing imperative programming with ((Lisp)) syntax is hugely annoying. OCaml actually annoyed me in this regard too. Maybe I will like Haskell, since it seems principled about mutation.

This is a real misunderstanding, see my response to this comment here: https://news.ycombinator.com/item?id=11412392

People think that there could have been some "Church basis" for computing. In other words, the whole Lisp machines thing was folly. It's rightly in the dustbin of computing history.

FWIW I did many experiments in bootstrapping languages, with Python/Lua, OCaml, femtolisp, C, ... I eventually ended up with (a tasteful subset) of C++, which somewhat amazed me, since I've never been one to like C++. This is a whole other story, but it had to do with the fact that OCaml "needs" code generation with ocamllex and ocamlyacc/menhir, and I was looking at how Julia is bootstrapped Lisp (impressive, but not what I want), etc.

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