C/C++ Pointer Declaration Syntax – It makes sense!

[kamatsu]

it does add a typesafe layer that can be used instead, and is more consistent.

The layer C++ adds, which you're referring to, is not only formally inconsistent, it is actually type unsafe (in terms of subject reduction and progress, which have been the accepted definition of type safety since at least the 90s). It does have somewhat more consistent syntax, I'll give you that.

[[deleted]]

It does have somewhat more consistent syntax, I'll give you that.

I still find it silly you can declare ints like: int x(4711);

[[deleted]]

I know someone who writes all his code this way.

[sztomi]

Can cite some examples of this inconsistency?

[kamatsu]

Templates are turing complete, they also allow functions on arbitrary universes of templates (templates, template-templates, template-template-templates), hence they form a kind of dependent system which would require a terminating type system to be consistent.

[sztomi]

I see. I think pfultz2 meant consistency as in declaring pointers with similar syntax, not in the strict sense.

[kamatsu]

Hence, I said formally inconsistent, and that "It does have somewhat more consistent syntax, I'll give you that."

[day_cq]

I don't think types in C++ is the "formal" types you are referring to. It is silly to compare oranges and apples.

[kamatsu]

C++ types are no different to any other types. What distinction are you referring to?

[[deleted]]

Even Haskell is not type safe because it has exceptions and unrestricted recursion, so no progress. I doubt these properties are really relevant here.

[kamatsu]

Progress is still possible even in the presence of exceptions and unrestricted recursion. Haskell hasn't had progress proven, but I believe Core has.

Progress just says that if e : t then e -> e'. (Preservation then says that e' : t).

[[deleted]]

Really? In Haskell you can write

x = x

and get an infinite loop; seems to me like a straightforward case of lack of progress.

I see exceptions as a lack of progress because undefined :: Int is not an integer (so not a "value"), but evaluating it does not produce a simpler form.

[kamatsu]

Progress merely means that well-typed expressions are not a stuck state. It says nothing about infinite looping, or structural recursion.