Exercise at end of Ch. 56 of "Programming in D"

[Era Scarecrow]

On Monday, 15 August 2022 at 03:19:43 UTC, johntp wrote:
> Your solution worked. I guess it is a little unnatural to 
> ignore the color.  I tried overriding the toHash() of Point, 
> but I don't know enough D to get it to work.  I wonder if that 
> could be a solution.

  Depends on what you're trying to do. Metadata unrelated to the 
value of the object i would ignore and not be part of hashing or 
comparisons. I've also done things for strings that held 
information like what original position in the array the data was 
(*for visually sorting testing*) and could yield me information 
while not interfering with the object/data in question.

  Though x+y as a hash seems terrible. I'd probably do 
((x+1000)**2)+y (assuming x and y are both going to be generally 
small ensuring the hash for location is unique. Then point(2,1) 
and point(1,2) have different hashes. But I'm not familiar with 
the exercise in question.