[Python-Dev] Every Release Can Be a Mini "Python 4000", Within Reason (was (name := expression) doesn't fit the narrative of PEP 20)

[Terry Reedy]

On 4/29/2018 11:51 PM, Guido van Rossum wrote:
> On Sun, Apr 29, 2018 at 10:45 AM, Eitan Adler <lists at eitanadler.com 
> <mailto:lists at eitanadler.com>> wrote:
> 
>     On 29 April 2018 at 01:34, Jeff Allen <ja.py at farowl.co.uk
>     <mailto:ja.py at farowl.co.uk>> wrote:
>     > On 27/04/2018 08:38, Greg Ewing wrote:
> 
>     > I speculate this all goes back to some pre-iteration version of FORmula
>     > TRANslation, where to its inventors '=' was definition and these really were
>     > "statements" in the normal sense of stating a truth.
> 
>     https://www.hillelwayne.com/post/equals-as-assignment/
>     <https://www.hillelwayne.com/post/equals-as-assignment/>
> 
> 
> That blog post was brought up before in this discussion (probably on 
> python-ideas). I have my doubts about whether it accurately represents 
> the historic truth though.

It is woefully incomplete in omitting the common usage of = to mean 
'equals' both as statement (comparison) and command (assignment) in both 
English and math.  I don't have any math books that I know of that 
predate computers, but I suspect the usage is not new.

The pre-C computer language history has a gaping hole: BASIC, which uses 
= for both assignment and comparison, was released May 1, 1964.  I don't 
believe the syntax allowed any ambiguity as to the meaning of each 
occurrence.  To me, it is the use of anything else that needs explaining.

-- 
Terry Jan Reedy