[Axiom-developer] Re: Embedding Axiom (Hickey and fold/unfold) Folding and generalization

[Tim Daly]

Martin Baker wrote:
> Tim,
>
> Thank you for these replies, I am learning a lot here.
>   

Yeah, Hickey is really an insightful chap. He sets the bar pretty high.

Many centuries ago I had to make the transition from using goto in general
to using goto in a structured form (Fortran did not have an else clause 
on If).
The hard part was the mental shift needed to do "structured programming" 
since
I had to discover the correct, disciplined control structures myself. 
There were
no textbooks as it was a "new" idea that unstructured goto was bad.

Now Hickey basically said "do not use loops". Hmmm... that's gonna be 
another
stretch, although I see why he suggests it and I agree with him. We have 
to learn to
use map/fold/take/etc. in disciplined ways to process Axiom's internal data.

And we need "reconsing" versions that return immutable but shared copies 
of the
list/vector/struct/etc., with versions that (per On Lisp) embed properly.

And we need to write in pure function form (not a stretch because I try to
do this now).

And we need (per SICP) to write embedded layering, fully factored forms.

I think all of these ideas will greatly benefit Axiom's internal 
restructuring,
including possibly making a parallel implementation much easier to achieve.
If nothing else at least the "coupling" will drop considerably as we 
stop using
special variables for maintaining mutable global state.

Tim