Name that tune

[Phil Last]

I think I'd have a lot more than my current 46 D-ops if I found it easier to name them.

I've coded the following conjunction many times but only ever in-line because I can't think of a name for it. It's a very clear concept but ...

      ummm←{⍺←⍵ ⋄ (⍺⍺ ⍺)⍵⍵ ⍵}

thus:

      f ummm g w ←→ (f w)g w

while:

      a f ummm g w ←→ (f a)g w

Anyone out there with an idea?

[Roger|Dyalog]

Since "hook" is

Code: Select all

    (f g) ⍵ ←→ ⍵ f (g ⍵)
  ⍺ (f g) ⍵ ←→ ⍺ f (g ⍵)

and

Code: Select all

    f ummm g w ←→ (f ⍵) g ⍵
  ⍺ f ummm g w ←→ (f ⍺) g ⍵

perhaps "left hook" is an appropriate name for ummm.

ummm also resembles the til operator in Iverson and Whitney's 1982 paper, Practical Uses of a Model of APL http://www.jsoftware.com/papers/APLModel.htm.

Code: Select all

    f⍨g ⍵ ←→ (g ⍵) f ⍵
  ⍺ f⍨g ⍵ ←→ (g ⍺) f ⍵

Til was one of the failed attempts to do "fork" with operators. I believe Arthur invented the definition and Ken invented the symbol. When Ken told Arthur the choice of symbol, he said, "Til, get it?" (Arthur did not. Do you?)