Re: [stack] Backus's Turing Award Lecture and Joy.

> On 3/22/07, John Carter <[email protected]> wrote:
> > With the recent death of John Backus, his Turing Award paper has
> > reemerged into the light...
> >
> > http://www.stanford.edu/class/cs242/readings/backus.pdf
> >
> > It is remarkably relevant in terms of discussing why Joy (and related
> > languages) are such a Good Idea.
> >
>
> Which parts are relevant to Joy? As I scan the paper, particularly
> the section-by-section summary at the end, I see some criticism of the
> prevalent style of programming. That seems relevant. But it looks
> like this 30 year old paper was advocating applicative state
> transition (AST) systems. Is there a connection between AST and Joy?
>
> --Joe

Here is a snippet which I think is relevant:

"In this section we give an informal description of a
class of simple applicative programming systems called
functional programming (FP) systems, in which "programs"
are simply functions without variables. The description
is followed by some examples and by a discussion
of various properties of FP systems.
An FP system is founded on the use of a fixed set of
combining forms called functional forms. These, plus
simple definitions, are the only means of building new
functions from existing ones; they use no variables or
substitution rules, and they become the operations of an
associated algebra of programs. All the functions of an
FP system are of one type: they map objects into objects
and always take a single argument.
In contrast, a lambda-calculus based system is
founded on the use of the lambda expression, with an
associated set of substitution rules for variables, for
building new functions. The lambda expression (with its
substitution rules) is capable of defining all possible
computable functions of all possible types and of any
number of arguments. This freedom and power has its ... "

Clearly Backus felt that there was elegance to a point-free language.

I would still like to hear John's response though, because he may have
some useful insights to share on the paper. I have a hard time
convincing others of the value concatenative style languages and I'd
like to know how to better leverage this paper.

Christopher Diggins
http://www.cdiggins.com