# NYCJUG/2012-04-11

Pascal's triangle, webGL 3D, directory trees, fat middle, array solution converted to streaming one, language design, emotional resonance of language decision, moral judgements, new programming languages, learning drill technique

Location:: Heartland

## Agenda

```             Meeting Agenda for NYCJUG 20120411
----------------------------------
1. Beginner's regatta: See "Pascal Triangle in APL and J.pdf", "Excerpts
from Algebra - An Algorithmic Treatment.pdf"

2. Show-and-tell: see "WebGL 3D Graphs on Google.pdf", "dirTreeIJS.doc".

A general solution to the "Fat Middle" problem?  See
"allAtOnceVsApplyAcross.pdf".

3. Advanced topics: What makes a good language?  See "PHP - a Fractal of

Why do we get so invested in a language?  See "Sucks vs Rocks in the
world of software.pdf".

What influences our judgement in general?  See "Moral Psychology - Six
Axes of Good and Evil.pdf".

4. Learning, teaching and promoting J, et al.: New languages: see "New
Languages and Why We Need Them.pdf", "Why Programmers Should Use Haskell
Now.pdf", "Parallel programming language ParaSail.pdf", "Simpler
Programming for Multicore Computers.pdf".

A method for teaching J?  See "Learning a New Language with Memrise.pdf".
```

## Beginner's regatta

We looked at code for generating Pascal's triangle in both APL and J from links referenced on the new and improved SIGAPL website. This is a good, fairly simple example for introducing those new to J - of whom there were a couple at the meeting - to a few powerful concepts like combinations (dyadic !) and power (^:).

There is a potentially useful online translation of Iverson's "Algebra - an Algorithmic Treatment" to use J examples. There is still work to be done on this web-based version, particularly in the section displaying J code and results - there is an end-of-line problem that strings out the 2D display into a line. Ed Cherlin is working on this but would welcome a programmatic fix he could apply to his HTML to rectify this.

## Show-and-Tell

There is a good example of using HTML5 to generate animated 3D plots on Google; if you use the Chrome browser, you can enter an equation and have it plotted almost instantly - see this example. This would be a truly powerful tool if we were able to use J instead of "standard mathematical notation" - this last phrase being, of course, an empty array joke.

We considered how to overcome array-programming languages' "fat middle" problem by converting a verb that works on an entire array to the verb plus an accumulator verb applied by means of a conjunction to a potentially large piece of data.