Re: mutable object model

On Thu, Nov 14, 2013 at 07:01:45 -0800, Alan Baljeu wrote:
> Richard O'Keefe wrote:
> > Are maps basically LIFE_like psi-terms?
> 
> Does anyone understand this question?  Google doesn't know either.

LIFE is/was a functional-logic programming language developed by
Hassan Ait-Kaci. Good online resources are a bit hard to find, but this
paper gives an introduction: http://www.din.uem.br/ia/ferramentas/tut_life.gz

Throwing together a bunch of quotes relevant to the psi-terms mentioned by
Richard: "LIFE is a generalization of Prolog. [...] Just as Prolog is based
on (first-order) terms, LIFE is based on psi-terms. [...] As a first
approximation, LIFE's psi-terms may be construed as record types. One could
say that they are to first-order terms what flexible records are to static
arrays. [...] One may view a psi-term as a generalization of conventional
Prolog terms in that subterm positions are specified by explicit numeric
keywords rather than implicit numeric positions."

So this would be a psi-term:
    car(manufacturer => "Ford", wheels => 4)
as would this:
    car(wheels => N)
*and* these two psi-terms can be unified, giving
    N = 4.

There's even more: There is a notion of inheritance between functors
("sorts"), so given appropriate declarations, one of the terms could have
the functor 'vehicle', for instance. It's an interesting read.

-- 
Gergö Barany, research assistant                 [email protected]
Institute of Computer Languages      http://www.complang.tuwien.ac.at/gergo/
Vienna University of Technology                       Tel: +43-1-58801-58522
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