[Jprogramming] Tacit vs. Explicit Paradigm and its Long-Term Impact

[Johann Hibschman]

Bill Harris <bill_harris at facilitatedsystems.com> writes:

> Does anyone do that with J?  I do take notes that way sometimes but not
> as often as I did with APL.  Perhaps that's partially due to my changing
> professional roles, but I still do analysis.  Perhaps that's partially
> due to much of my current analysis being done in R (*).  Perhaps that's
> because J gave us the ability to craft really powerful and really
> compact one-line programs that are hard to get right and expressive
> without a computer to test them.

[...]

> How do others react to this notion?  Do you regularly take notes in J?
> In what domains?  In tacit / explicit notation?

I find that J's dot- and colon-inflected symbols work well when typing
into a computer, but poorly when handwriting.  When working things out
on paper, I mostly use "traditional notation," with a melange of J and
APL symbols thrown in when they make sense.

However, speaking for myself, any notes that I want to be able to find
in a year have to be electronic.  I find J works very well for that, at
least for "computation-oriented" notes.  It works less well for more
symbolic things like stochastic calculus or Bayesian inference.

As an example, I just read a paper on methods of combining multiple
econometric forecasts into a smart consensus and used J to write down
the different "win" metrics discussed in the paper.  It was handy and
concise, with one big caveat: I completely ignored any issues with
missing data, assuming that all the arrays were dense.  That was fine
for note-taking, but if I wanted to implement it "for real", I would
have to carry around a mask array and update it on each step, which
would make the notation much less appealing.

Right now, I'm implementing the "for real" version in R and appreciating
the built-in missing-value support.

Johann