Fwd: A typing question

[dn]

On 30/10/2022 11.59, Paulo da Silva wrote:
>> Solution (below) will not work if the mention of Foos in GLOBALS is a 
>> forward-reference. Either move GLOBALS to suit, or surround "Foos" 
>> with quotes.
> This is the problem for me. So far, without typing, I used to have some 
> config and globals classes, mostly to just group definitions an make the 
> program more readable. A matter of taste and style.

Agreed, a good practice.


> Now, "typing" is breaking this, mostly because of this forward reference 
> issue.

As a first step, use the quotation-marks to indicate that such will be 
defined later in the code:-

> class GLOBALS:
>     Foos: Optional[Foos]=None 

class GLOBALS:
     Foos: Optional["Foos"]=None


Later, as gather (typing) expertise, can become more sophisticated, 
as-and-when...


> The funny thing is that if I replace foos by Foos it works because it 
> gets known by the initial initialization :-) !

Is the objective to write (good) code, or merely to satisfy the 
type-checker?

Something that is misleading is not going to be appreciated by others 
(including the +6-months you), eg

a = a + 1   # decrement total

Typing is not compulsory, and has been designed so that we can implement 
it a bit at a time, eg only one function amongst many contained by a 
module - if that's the only code that requires maintenance/update.

Best not to create "technical debt" though!

-- 
Regards,
=dn