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


On Sunday, April 29, 2018, Eitan Adler <lists at eitanadler.com> wrote:

> On 29 April 2018 at 01:34, Jeff Allen <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://en.wikipedia.org/wiki/Assignment_(computer_science)

C and C++ are '=' and '=='.

The Sympy solver, for example, solves Eq(lhs, rhs) equations and
expressions that are assumed to be equal to zero.
http://docs.sympy.org/latest/tutorial/solvers.html

The sage solver defines __eq__ (==) so expressions with variables produce
symbolic equations and inequalities (relations).
http://doc.sagemath.org/html/en/reference/calculus/sage/symbolic/relation.html

PyDatalog defines __eq__ so that expressions with variables produce logic
queries.
https://sites.google.com/site/pydatalog/Online-datalog-tutorial

The assignment Wikipedia article lists languages other than C and C++ which
chose = and == for assignment and definable equality testing.

https://en.wikipedia.org/wiki/Equality_(mathematics)
  https://en.wikipedia.org/wiki/Extensionality
https://en.wikipedia.org/wiki/Logical_equality



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> Eitan Adler
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