Just another example of missing string interpolation

[kdevel]

On Friday, 13 October 2023 at 17:38:23 UTC, bachmeier wrote:
> On Friday, 13 October 2023 at 15:34:59 UTC, kdevel wrote:
>
>> Your functions `foo` and `bar` both not only make calls to 
>> `interp` but they
>> also necessarily contain, in order to succeed, the name of the 
>> variable.
>
> Yes

But then you can't re-use `foo` with another string, e.g.

     "String needing interpolation to insert ${yold} and ${ynew}."

>> Your approach creates more dependencies between unrelated 
>> components than necessary.
>
> Then don't use it? The goal of programming is to get the right 
> output.

Your code does not meet that requirement.

>> How do you unittest `foo` and `bar`?
>
> The same as any other function.

Having the signature of `foo` and `bar` alone I am not able to 
write a unittest.

>> The dependencies can easily be avoided if `foo` and `bar` only 
>> returned the value of the computation, the results are stored 
>> in the AA given as `subs` in the call to `interp`.
>
> I prefer less complicated code to code that imposes arbitrary 
> restrictions.

In your code of `foo` and `bar` you have to assemble the AA and 
call `interp` twice compared to once. I would call my approach 
less complicated and my `foo` and `bar` versions do not suffer 
from the arbitrary restriction of beeing applicable only to 
strings having a predefined variable name.