On 30 November 2012 16:17, Bo Jacoby <[email protected]> wrote:
> J is a rich language, and it might be a good idea to define an elementary
> subset for beginners.
Couldn't agree more.
A simple startup configuration file. Define verbs for trig functions so
they don't look stupidly arbitrary.
Some other elementary functions too, like polar2rect and rect2polar
conversions that act on vectors (none of this xfy binary stuff here
please), you know, stuff like you can find on *calculators*.
Define dot-product, matrix-multiplication, cross-product, determinant, etc,
as user-friendly built-in verbs. When I am a beginner, I DO NOT, repeat
NOT want to know about the . operator at the level of the jdict, it is a
highly advanced subject, intriguing - yes, but not for newbies. Yet I do
want to do matrix ops. I was told this was a language for linear algebra.
It would probably be a good idea, then, if we could do some linalg -
straight out of the box - without serious brain damage. I have had abuse
hurled at me by math teachers who have seen J's linalg primitives (LOL).
Add some nice libs for equation solving while we're at it. Simultaneous
and also some numeric solvers. This is what people want. A language, not
an assembler for a language.
> J is a nice calculator for elementary computations. You can do a lot of
> computing without knowing anything about binomial coefficients and taylor
> expansions and capped forks.
Agree with the first two, NO way on the third. Even the 13 verb gives you
capped verbs, there is no way to begin learning J without it. Also they
solve the problem of having to figure if you should use At or Atop,
invaluable for a beginner who hasn;t quite mastered rank yet.
This problem, which once again gives rise to a long thread, could easily be
solved by a highly visible Programming FAQ page, with lots of links to.
Deal with capped forks, @ and @: and why you can't have things like +/ a
b c You know, the questions people *keep asking*. Remove ancient
irrelevant stuff like the use of x. and y. We are not at J401 any more.
> If you need to understand everything in order to be happy, then you may be
> unhappy. I taught my son elementary APL when he was 10 years old, and he
> loved it!
>
Would he have been just as happy at 14 when he had to use the cosine rule
to solve a triangle? Would he really prefer
cosrule_getang =: 13 : '_2&o.(((+/*:}.y)-*:{.y) % */ 2, }.y)'
or
cosrule_getang =: [: _2&o. (([: +/ [: *: }.) - [: *: {.) % [: */ 2 , }.
to
cosrule_getang := (Aa,B,C) -> acos((B^2+C^2-Aa^2)/(2.0*B*C));
Just wondering...
These are simple enough things to do, and I speak as a J newcomer. There's
not many languages you can say that about after two and a half years! The
Zen of J, grasshopper.
Incidentally, is there a way to cap a monadic hook on the left?
For example (=<.) was mentioned, but obviously it allows dyadic arguments,
and fails if they are offered.
Short of wrting monad : 'y=<.y' is there a way I can keep it monadic (and
implicit)?
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
