The Question of Braces in APLASCII 4367

When I first ordered some Memorex terminals for use by the APL-700 team no specifications had been made t that time by the APL community of that time for the six additional character positions that ASCII provided.

My firrst action was to contact Ken Iverson who at that time worked and lived a short distance away. Ken stated that he had no preferences.

And here's where my memory gets a bit foggy. My recollection is that my initial set of additional characters were

1) top key shifted -- dollar sign

2) top key unshifted -- cent sign

3) middle key shifted -- reverse sigma

4) middle key unshifted -- sigma

5) bottom key shifted -- right brace

6) bottom key unshifted -- left brace

but the middle keys might have been

4) middle key shifted -- three dots in an upward pointing triangle

5) middle key unshifted -- three dots in a downward pointing triangle

The sigmas relate to a conversation I had with Ken Iverson in the early seventies when he felt that the notation for reduction and the at that time not yet implemented scan were in contradiction to the rest of APL -- the notion of operators having not yet been part of APL, reduction, scan, inner product and outer product being considered as "composite functions".

I'm not sure what the inspiration for the three dots was.

And, as I've already mentioned, three of those characters were changed to diamond, left tack, and right tack. I have no memory of just what characters were on the Tektronix 4014 when it was shown at the Atlanta conference and as for the memorex my recollection was that they used the cent sign and sigmas, but I've received disagreement as far as the sigmas.

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