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I see these as a more sophisticated way of dealing with NULL. It allows me to define alternative default behaviour beyond just throwing an undeclared exception.

by rusk 8y ago

I see these as a more sophisticated way of dealing with NULL. It allows me to define alternative default behaviour beyond just throwing an undeclared exception. They are still NULLs however under the hood and I still need to do the work of defining what I want to happen when they occur. It's just neater.

icebraining 8y ago
You can conceptualize the Maybe based on the NULL, but there's no point in the compilation or runtime in which they actually become NULLs, it's just a regular container value.
- rusk 8y ago
  Which is the same as if I go and ensure a default "noop" value is assigned ... it's logically a NULL. I don't know anything about it except that it hasn't been assigned.
  - icebraining 8y ago
    It's not a NULL. A NULL is a value that is considered by the type system to be a valid instance of a given type, except it doesn't actually fulfill the type's contract. A Maybe is a completely different type, much like a list or a map or a tree.
    - rusk 8y ago
      Well at this stage you're just being narrow minded. I think if you read back over this thread it should be clear what I mean. I proposed that NULL has a purpose. You proposed that Option obviates this. I stress that it's just a neater way to manage the conditions you don't need to model. You point out that in terms of implementation it's different, where I explain that still, logically it's the same thing. Of course NULL has a very specific meaning in the structure of the language, and when you start using things like Options it makes managing NULL easier, but it's a rose by another name, gift-wrapped, and bundled with some plant food. Logically however, at the point where you're modelling your problem it's the same.
lmm 8y ago
They're not null. You might use them to represent the same thing that you use null to represent, but the type system won't let you use them in expressions that aren't explicitly built to accept them.

by rusk 8y ago

icebraining 8y ago

You can conceptualize the Maybe based on the NULL, but there's no point in the compilation or runtime in which they actually become NULLs, it's just a regular container value.

rusk 8y ago
Which is the same as if I go and ensure a default "noop" value is assigned ... it's logically a NULL. I don't know anything about it except that it hasn't been assigned.
- icebraining 8y ago
  It's not a NULL. A NULL is a value that is considered by the type system to be a valid instance of a given type, except it doesn't actually fulfill the type's contract. A Maybe is a completely different type, much like a list or a map or a tree.
  - rusk 8y ago
    Well at this stage you're just being narrow minded. I think if you read back over this thread it should be clear what I mean. I proposed that NULL has a purpose. You proposed that Option obviates this. I stress that it's just a neater way to manage the conditions you don't need to model. You point out that in terms of implementation it's different, where I explain that still, logically it's the same thing. Of course NULL has a very specific meaning in the structure of the language, and when you start using things like Options it makes managing NULL easier, but it's a rose by another name, gift-wrapped, and bundled with some plant food. Logically however, at the point where you're modelling your problem it's the same.

lmm 8y ago

They're not null. You might use them to represent the same thing that you use null to represent, but the type system won't let you use them in expressions that aren't explicitly built to accept them.