Re: origin of := and =: -

If I remember well, the notation A:=B for "A becomes B" was introduced in computing practice by John W. Backus in an article about a proposal for a computer language (later known as ALGOL58, a forerunner of ALGOL60):

John W. Backus: The syntax and semantics of the proposed international algebraic language of the Zurich ACM-GAMM Conference. IFIP Congress 1959: 125-131

See http://www.informatik.uni-trier.de/~ley/db/conf/ifip/ifip1959.html

I have my paper copy of the IFIP 1959 proceedings at my office at Delft University, so right now I cannot check this.

Johan E. Mebius


Herman Rubin wrote:

>In article <433bf53b$0$49021$14726298@xxxxxxxxxxxxxxx>,
>Andreas Moser  <spam@xxxxxxxxxxx> wrote:
>
>>I was wondering who introduced the extremely useful notation of := for
>>defining symbols. It is a lot better than the old '', because it shows
>>which side is defined by which, through the position of the :
>
>
>>Andy
>
>
>This was introduced in mathematical logic BC (before
>computers).  I am not sure, but I think it was by
>Whitehead and Russell.
>

.