At the Beginning, There Were Two - Inventing the PC - page 7

Kenneth Iverson deliver-
ing his lecture “Teaching
APL ” during the 1980 APL
Users' Meeting in Toronto.
(Source: York University
Computer Museum,
photographer unknown.)
more general than conventional mathematical notation could
provide. “The mathematical notation that I had been raised
on just wasn't adequate,” explained Iverson. “So I turned my
attention to notation. And having had in my [doctoral] thesis
work experience in implementing things on a computer, I al-
ways thought, as I developed notation, I always had in mind
that this is something that should be actually implemented. So
that's what started me on what became APL .”
Iverson notation had its roots in conventional mathematical
practice. “I used accepted mathematical notations unchanged,”
Iverson remarked in a July 1977 interview for Electronic Design .
“I was perfectly happy with the conventional +, -, ×, and \ used
in grade school and up.” 3 But as he went from one application
to another, he found needs and reasons to expand the conven-
tional notation by introducing new symbols.
For Iverson, a notation system was an essential tool of thought,
a systematic and unambiguous foundation for precise and ef-
ficient reasoning. Essentially, Iverson notation was a mathemat-