Re: [Denemo-devel] denemo with scheme interpreter.

[Richard Shann]

On Thu, 2008-08-21 at 20:36 +0200, Nils Gey wrote:
> Ok, if its just a news then leave it a news.
> I will look around, but you meant guile, am I right?
The language is called Scheme (a dialect of Lisp), and Guile is (I
think) an implementation of it. (The Guile webpages describe it as an
interpreter for Scheme, by which I think they just mean that it is a
library that provides a function to interpret texts of Scheme.)
> 
> So Swig is gone?
Yes. Swig completely peters out when you try to use the interface code
it generates in the opposite direction to what the developers have in
mind. (That is, Denemo is running in a loop and calls out to have
something interpreted. As opposed to a Ruby interpreter running in a
loop calling out to have Denemo perform some action on its data.)
There is some trace of this in Tcl webpages, but none at all on the Ruby
pages - in fact I couldn't even see any interfacing tools on that site,
it was heavily oriented towards people writing Ruby code, not engineers
wanting to bolt Ruby on to something. I didn't persist as Scheme will be
the solid, reliable choice: the task of translating from one to the
other (on the fly) is generally very straightforward - its the strongest
feature of these languages, you just write something that slurps up one
piece of text and spouts out another. In fact, the year I spent writing
Lisp was just this, I was designing a Database query language for
content-addressable image databases and it was literally just a question
of turning the database queries into Common Lisp which then manipulated
the data.

Something else that might interest you - Scheme may appeal to you! You
can learn it in half an hour: it is a minimalist language. There are
only a tiny number of constructs and everything follows strictly from
there, strictly logically. You may be left wondering what Denemo has
done, but not what Scheme has told it to do. 

This is in the wildest contrast with a language like Perl, which has an
enormous amount of ifs and buts under the bonnet, trying to guess what
it is you might be wanting to do, and then doing it. (Whether that was
what you wanted or not).

The downside is that I concluded last time that Lisp is not really
suitable for human beings. But there are people who are addicted,
perhaps because it hurts the brain (a sort of masochism), or perhaps
people are just different.

Richard