Re: Lack of software abstractions

On 25-Jan-07, at 5:54 PM, Miller, Raul D wrote:

> dydre wrote:
> > 1.  The notation J layers many things in unique ways and
> > they are not completely documented.
>
> I don't know what this means.
>
> (I know what 'needs to be documented' would mean, but I
> do not know how to distinguish between contexts where the
> above is an issue and where it is not an issue.)
For example - a few terms from the J Vocabulary:


< Box • Less Than
<. Floor • Lesser Of (Min)
<: Decrement • Less Or Equal

> Open • Larger Than
>. Ceiling • Larger of (Max)
>: Increment • Larger Or Equal

_ Negative Sign / Infinity
_. Indeterminate
_: Infinity

+ Conjugate • Plus
+. Real / Imaginary • GCD (Or)
+: Double • Not-Or

* Signum • Times
*. Length/Angle • LCM (And)
*: Square • Not-And

- Negate • Minus
-. Not • Less
-: Halve • Match

% Reciprocal • Divide
%. Matrix Inverse • Matrix Divide
%: Square Root • Root

^ Exponential • Power
^. Natural Log • Logarithm
^: Power (u^:n u^:v)

$ Shape Of • Shape
$. Sparse
$: Self-Reference

Can you show me another language where the same sets of concepts are  
mapped to equivalent words - for example in C++ or Java or any other  
language of your choosing, is there a concept such as Double and Not- 
Or combined in a single word?

This is not a criticism of J.  Once understood, there is power in the  
layering of the concepts.  However, many concepts of this nature in  
Dr Iverson's Dictionary of J language are left as an exercise to the  
student which I must say is not without its charm.  However, having a  
more complete reference might be more expedient for some students.


> >  (c)  Primitives of APL did allow a level of abstraction that did
> > simplify underlying complexity.  J permits you to compress complex
> > ideas but it is not necessarily by simplifying an underlying
> > complexity.
>
> I don't know what this means.
>
> --
> Raul

Sorry I am too busy to create a good example of this.  I do not have  
an APL environment on my machine.  So far I am using J in a J console  
under my terminal window because I find it easier
than the provided environment that can cause overwriting in the log.

This brings up another point for me.  I imagine people who actual use  
J have devised an environment for themselves but I have nothing  
equivalent to the simple concept of saving an APL workspace.

Donna
dydre-rieW9WUcm8FFJ04o6PK0Fg@xxxxxxxxxxxxxxxx