On Sunday, 19 May 2013 at 18:05:03 UTC, Idan Arye wrote:
These are the assumptions I'm working with:
- We can't use a nullable reference
- We can't initialize the reference upon declaration to it's
real value.
If you can't initialize the value, you got to assume when you use
it that it may not have been initialized and handle that case.
You need either an Option (where you have to be explicit about
what you do when the thing is null) or a Maybe (where null is
ignored and Maybe "contaminate" every result depending on a maybe
value).
The first assumption is required because we want to describe
how the bug scenario deadalnix brought up would look like if
references were non-nullable. The second assumption is required
because if we could initialize the reference upon declaration
to it's real value, we should have just done it in the first
place and avoid the whole race hazard.
But that is the whole point ! The damn thing should have been
initialized in the first place to avoid the bug. And this should
have been caught at compile time with any sane type system.
And this is the exact problem with nullable by default : plenty
of stuff ends up be null is some weird situation that almost
never occurs when they are assumed not to be and the program
crashes. NullPointerException now return 4 millions result on
google, which is probably around once per java developers.
Now, I'm not saying the solution I presented is good - I'm
trying to show that given those two assumptions, we are forced
to use this bad solution.
This solution is complex, do not make any sense in a strongly
typed language and don't even solve the presented case.
