Proposed new syntax

[Rustom Mody]

On Tuesday, August 15, 2017 at 5:48:43 PM UTC+5:30, Steve D'Aprano wrote:
> On Tue, 15 Aug 2017 02:54 pm, Rustom Mody wrote:
> 
> > On Monday, August 14, 2017 at 10:35:22 PM UTC+5:30, Terry Reedy wrote:
> [...]
> >> Suppose stdin contains "a\nb\nc\nd\ne\nf\ng\n".
> >> What is the meaning of
> >> [input(f"response{i}") for i in range(6)]?
> >> In Python, the predictable result is
> >> ['a', 'b', 'c', 'd', 'e', 'f']
> >> It would not be with some of Rustom Mody's 'equivalents'.
> 
> Indeed. Terry has hit the nail on the head here. Python's documented semantics
> is predictable and deterministic, and the documented semantics of
> comprehensions are explicitly based on sequential for-loops.
> 
> To continue to insist, in contradiction to the documentation, that list comps
> might legitimately operate in arbitrary order is simply irrational. If they
> behaved as Rustom is insisting they might, it would be a bug in the
> implementation.

I know that list-comps behave like the l2r-pass-doing-appends as SPECIFIED
in the docs.
In my view the IMPLEMENTATION is correct wrt that specification
Whereas the SPECIFICATION, in being over-specific is wrong

In the same way that if someone explaining C were to say that the '+' operator
is (the SAME AS) ADD x86 instructions and then proves that case by showing gcc -S's output.