To answer how this _could_ work, Undefined would be a new NoneType that is
falsey (just like None) can't be reassigned (just like None) and does
everything else just like None _except_ that when it is passed as a function
argument, the argument name is bound to the default if it has one instead.
I am not sure I understand your example
> notdefined = None
> def foo(x=undefined): # here
> notdefined = x
> return wrapped_function(x) # there
> foo()
> print(notdefined)
This would call wrapped_function with "undefined" so it would use the default
if present, and print None because notdefined in foo is only in that scope?
Did you mean to use a global notdefined in foo? In which case it would print
undefined ?
In your example there is no default to use... it would be this case:
def foo(x=undefined):
return bar(x)
def bar(x=1):
return x
print(foo()) # 1
print(foo(2)) # 2
To be clear, I am _not_ +anything for this, I was just saying that I think this
is what is really be asked for here. I am -0, I can see there being value, but
that value is largely superficial and the possible can of worms is definitely a
writhing one. The only problem it solves is allowing wrappers to fallback to
their wrapped functions defaults, but at a fairly high cost.
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