On 11/14/2019 4:16 PM, R.Wieser wrote:
If you mentioned what problem you are trying to solve
1) Have value
2) use value in procedure 1
3) use updated value in procedure 2
4) use again updated value in procedure 1, 2 or maybe 3
For the sake of learning I'm now going over all of the possibilities to see
if and how they work.
> For that I've already excluded globals and the
practice of feeding the value as an argument to the procedure and than store
its result as the new one.
This is discouraged for anything very complex.
I've also excluded using a class object and put
the code in there,
This is the standard way in Python and other OO languages. By
'excluded', do you mean 'rejected', or 'tried that, what else is there?'
as well as faking a "by reference" passing by using a tuple.
One has to pass a mutable, such as list, set, dict, or user class instance.
"nonlocal" looked to be another option, but it appears to be rather
limited in its application.
Closures are standard in functional languages and are less limited than
you seem to think. But you have to enclose (nest) many or all of the
functions that directly rebind 'val' (else one might as well use a
global value).
def valclass(val):
def set(newval): # For functions not defined within valclass.
nonlocal val
val = newval
def get()
return val
def proc1(args)
nonlocal val
...
dev proc2(args)
nonlocal val
...
return setval, getval, proc1, proc2
# return {'set':set, 'get':get, 'proc1':proc1, 'proc2':proc2}
setval, getval, proc1, proc2 = valclass(3)
# val = valclass(3)
In short, the /ways to the goal/ are (currently) important to me, not the
goal itself (I'm sure that apart from the "nonlocal" one all of the above
are viable, and I thus can get /something/ to work)
--
Terry Jan Reedy
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