Nostalgia

[JohnS|Dyalog]

This will bring tears to the eyes of the old folk:
Whatever happened to O<backspace>U<backspace>T ?

[Roger|Dyalog]

See http://keiapl.org/anec/#emulator .

Since the APL\360 source code http://www.computerhistory.org/atchm/the-apl-programming-language-source-code/ is now publicly available you can build your own version of it and bring O<bs>U<bs>T back to life.

[neeraj]

ok so I admit I don't know (that is a good thing) what O<backspace>U<backspace>T is ? Will somebody shed some light on this?

[Roger|Dyalog]

"Quote-quad" input t←⍞ is formerly used extensively to solicit terminal input from the user. If the programmer made a mistake, e.g.

      ∇ t←foo
       l20:
        t←⍞
        →l20
      ∇

then there would be no way to interrupt or escape from the erroneous program. The sequence o<backspace>u<backspace>t was introduced so that if the user entered that, an INPUT INTERRUPT is signaled on the line that contains the quote-quad input.