Yoann Padioleau wrote:
> I have to admit that perl can be cryptic, but certainly not Ruby nor
python.
> python have too continuations.
Python can be cryptic, and its continuations are an example of that - a
hacked feature that wasn't designed into the language from the beginning,
and it shows. Besides, what's up with that __init__ thing? :)
> The only advantage i see in scheme over other langages, is its powerful
macro system.
> That's all.
There are many more advantages, which perhaps you haven't seen yet. I say
this as someone who only found Scheme after many years of working with many
languages, including all the usual suspects, like Pascal, C, C++, Java, and
scripting languages including Perl and Python.
Some high-level examples of the advantages of Scheme include:
* A very regular syntax, which along with a built-in syntax reader,
contributes to the ability for programs to easily read and manipulate other
programs. Macros take advantage of this capability, but it can be
surprisingly useful in all sorts of ways that don't involve macros.
* Related to the above point, code and data are represented using the same
syntax, which aside from the benefits for automated manipulation of
programs, also makes it very easy to persist high-level structures in a very
usable and maintainable way. The scripting languages tend to use XML for
this kind of purpose, which entails a lot of often unnecessary complexity
and overhead.
* Very well-designed integration of features such as closures,
continuations, and macros, which allows these features to be used together
to build domain-specific languages. It's not just the presence of these
individual features, but how they interact. SCSH is an example of this - it
provides the kinds of benefits which Perl apparently needed to embed into
the core of the language. Scheme is a tool for building languages, in a way
that none of the scripting languages can achieve. This point assumes that
you're familiar with the benefits of the domain-specific language approach
to development.
* As a consequence of the above point, Scheme is a multi-paradigm language,
capable of supporting functional programming, OO programming, logic
programming, goal oriented programming, etc., with language extensions that
support these features.
* The ability to achieve very high performance, often on par with or even
exceeding that of C or C++. It's easy to design a powerful high-level
language that's slow - it's much more difficult to design a powerful
high-level language that's also fast. The best examples of the latter are
all either functional or semi-functional languages, including Scheme. This
is partly because the functional paradigm supports automated "algebraic"
program transformations that can be performed by compilers in order to
achieve better performance, and allows programs to be translated into
lower-level languages in the most efficient possible ways.
However, I think you're right that the SCSH FAQ doesn't quite succeed in
communicating to someone who is comfortable with traditional scripting
languages, why they should throw out all the arbitrary syntax they've worked
so hard to memorize, and instead learn something that's more cleanly
designed for extensibility and power. Part of the problem is that fully
describing and contrasting these capabilities to those of the "scripting
languages" would require an entire series of articles.
Anton
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