Panicz Maciej Godek <godek.maciek@gmail.com> writes:
>
> Maybe you should explain why there are so many implementations of
> Scheme in the first place? (That isn't the case for Python, Java or
> Perl)

Because it's too easy to make a standards-compliant implementation
because the standards ask for too little from compliant implementations.
And/or other reasons; don't really know your intent with the question.

>     [...]
>
>     That's the Grand Dream, but I don't even think it's *that* far
>     away:
>
> Had I such a "Grand Dream", I'd go with Python, because they already
> have that.

Python still lacks many of Scheme's greatest features. :-)

> Scheme has very different traits, and very different purpose. The
> position of Python stems from its particular notion of elegance, which
> -- although isn't as extreme as Scheme's -- is easier to grasp to the
> masses. This especially regards syntax. Python has a very intuitive
> syntax for its basic notions (including dictionaries). Lisp has "all
> those hairy parentheses", which apparently very few people can
> appreciate, although they help to work with the code greatly, allowing
> to see beyond language's limitations.

S-expression syntax, allowing things like Paredit, is one of Scheme's
many virtues over other languages.  So I would like to use Scheme, not
Python.  Currently I can't.  (I can use Guile, but it still misses some
"batteries.")

>     I find it daunting that it took us 106 whopping SRFIs to reach a
>     *basic* socket API! Scheme could have been taking over the world
>     by now. : -)
>
> Not sure what you mean by "taking over the world". That there will be
> many people using it? There won't. That there will be important
> systems based on it? Don't think so.

Why not?

> Scheme's power to change the world doesn't stem from standardized
> APIs, but (hopefully) from SICP and the way it affects thinking about
> computer systems.

Why even bother with something like Guile if the only worth of Scheme
were pedagogical?

>     And as amazing as it would be if that huge pool of libraries
>     existed specifically as Guile modules, I'm not sure if it's
>     realistic.
>
> Somehow I can't get amazed with that vision.
> The best thing that Scheme does for programming is that it promotes
> writing software that can be read, and not only executed. What you
> claim to be essential here seems to be a rather minor detail from that
> point of view.

Libraries *are* software.  Currently people *don't* write any of that
"software that can be read" except in small groups.

>     Python lacks many of Scheme's greatest features.
>
> The advantage of which rarely manifests in everyday practice,
> especially if you're not used to working with s-expressions (most
> programmers I know haven't got a clue what those are).
> I recommend that you read this:
> http://norvig.com/python-lisp.html

I'm wondering more and more why you use Scheme if you think it has no
advantages over Python.

>     If I can't *rely* on the constant-time factor, that's useless. If
>     it's reliable, then you specified something effectively equivalent
>     to a hash table API.
>
> Sure. The only difference is the cognitive overhead. If you could use
> plain "cons" for constructing hash tables and vectors, that would be a
> big win, because you would remove another weakness and restriction
> that makes this additional feature of yours necessary.

How can one implement such a miracle cons that constructs a list,
vector, or hash table depending on the programmer's wishes?

Maybe you're thinking of something like PHP's arrays, which are somehow
vectors and hash tables at the same time.  It's pretty terrible...

Scheme does no such muddying of what should be distinct abstract data
types, thankfully.

>     > Which "said fundamental features" do you mean?
>
>     Hash tables, weak references, sockets, threading, regular
>     expressions, record type subtyping, procedural macros, delimited
>     continuations, etc.
>
> Hash tables, weak references and threading are just implementation
> details that a programmer usually shouldn't care about. Delimited
> continuations are an academic curiosity, and sockets and regexps are
> just a specific domain (I'm sure you could easily find plenty of
> others; anyway, they are by no means fundamental)

"Hash tables" are understood to be a data type providing amortized
constant-time key-value lookup.

Time complexity is part of program semantics, not implementation.

Sockets are fundamental because you can't implement them as a library. 

Regexps
might actually be possible to implement as a portable library, though it
will probably be pretty slow.

These things could not possibly be any more fundamental.

> You can surely implement threads using call/cc, or even delimited
> continuations.

No, you can't.  Your program will run on one core.

> You can implement hash tables and weak references (and
> anything you please) using vectors.

No, you can't.  Hashing requires implementation support.

>     It's an actual problem if a Guile user can't use any Scheme
>     library that wasn't written with Guile in mind. At the *very* very
>     least, the user will need to add define-module boilerplate; in
>     practice she or he will probably need to do a lot more.
>
> Somehow to me it has never been a problem.
> What has been the actual problem is the multiplicity of ways that
> things can be expressed in any Scheme implementation (like the fact
> that Scheme provides both lists and vectors as collections, and that
> some implementations also provide multi-dimensional arrays)

I suspect that the things you use programming languages for differ
greatly from what most programmers use them for.

I don't feel very motivated to continue this discussion since we seem to
see things way too differently.