On mer., Mar 27, 2019 at 5:00 PM, python-list-requ...@python.org wrote:
On 27/03/19 09:21, Alexey Muranov wrote:
Whey you need a simple function in Python, there is a choice
between a
normal function declaration and an assignment of a anonymous
function
(defined by a lambda-expression) to a variable:
def f(x): return x*x
or
f = lambda x: x*x
It would be however more convenient to be able to write instead just
f(x) = x*x
(like in Haskell and such).
Have this idea been discussed before?
I do not see any conflicts with the existing syntax. The following
would also work:
I don't know. Something like the following is already legal:
f(x)[n] = x * n
And it does something completly different.
Thanks for pointing out this example, but so far i do not see any issue
with this.
Of course assignment (to an identifier) is a completely different type
of operation than in-place mutation (of an object) with __setitem__,
etc.
In
<...> [<...>] = <...>
the part to the left of "[<...>]=" is an expression that is to be
evaluated, and only its value matters. Here "[]=" can be viewed as a
method call, which is distinguished by the context from "[]" method
call (__getitem__).
In
<identifier> = <...>
the <identifier> is not evaluated.
I still think that
<identifier>(<identifiers>)...(<identifiers>) = <...>
is unambiguous. The following seems possible too:
a[m][n](x)(y) = m*x + n*y
It would be the same as
a[m][n] = lambda x: lambda y: m*x + n*y
Here a[m] is evaluated, and on the result the method "[]="
(__setitem__) is called.
Basically, "()...()=" seems to technically fit all contexts where "="
fits...
Alexey.
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