To add to the confusion, while
( {+⌿ ÷ ≢} y) ≡ ( +⌿y) ÷ ≢y
(x {+⌿ ÷ ≢} y) ≡ (x+⌿y) ÷ x≢y
whatever that does.
I completely agree, it’s quite obscure, especially if one is not accustomed to
tacit definition. This by the way is a fork, and is basically a way to avoid
parentheses. More useful however is the bonding operator, which I know
is functional in Dyalog:
toCelsius ←((5÷9)∘×)∘(-∘32)
toFahrenheit ←toCelsius⍣¯1
toFahr toCelsius 212
212
Which can be very handy.
Louis
> On 05 Mar 2016, at 16:33, Elias Mårtenson <loke...@gmail.com> wrote:
>
> On 5 March 2016 at 23:28, Louis de Forcrand <ol...@bluewin.ch
> <mailto:ol...@bluewin.ch>> wrote:
> That would be a great idea. However, it would indeed take not only quite a
> bit of
> time to set up, but would also need constant checking to make sure the updates
> in the main branch don’t conflict with additions.
> While I just said that I believe the main branch should probably concentrate
> on
> the standard, one of the things I’ve really fallen in love with in J and that
> is
> completely missing in standard APL is tacit definition. Not only does it allow
> inversible functions and idiom detection for optimisation, but it is just
> simply
> so elegant:
> mean ← +⌿ ÷ ≢
>
> This is where we disagree, but nothing wrong with that. I can certainly
> understand why someone would like that construct, but I just don't like it at
> all. I think this is probably the least clear and easily the most confusing
> language construct I know of in any language I have tried.
>
> I would certainly like to see some simpler way to define such functions
> without multiple levels of lambda definitions, but the J model is not the
> right way, in my opinion.
>
> Regards,
> Elias
