> Is it possible to implement foo? Trivially, the answer is no, as Void is a type that contains no values, so it’s impossible for any function to produce a value of type Void
That's actually not really correct. Or rather, it is technically correct but it will confuse the readers who work in languages like Java.
While void in languages like Java means that the result of the function cannot be used or has no meaning, it is NOT equivalent to types like the bottom type of Haskell. Because that would mean that the function can never return.
Rather, void is similar to the "unit type" (https://en.wikipedia.org/wiki/Unit_type) which does have a value. It's like an empty tuple. It contains no information other then "the function call has finished". (and of course in languages with exceptions, this means that no exception was thrown)
Otherwise, I like the article. More people should read and understand this way of thinking.
`Void` is not equivalent to the unit type. Haskell _has_ a unit type, called `()`. A return value of `Void` represents a function which is unimplementable, or which never terminates. It can also represent an unreachable possibility, e.g. in the type `Either Void a`.
Yeah - I just wanted to emphasize that this article will be confusing for most developers. Since most are used to void from languages like Java. And the meaning of that void is different from the one in Haskell.
That's actually not really correct. Or rather, it is technically correct but it will confuse the readers who work in languages like Java.
While void in languages like Java means that the result of the function cannot be used or has no meaning, it is NOT equivalent to types like the bottom type of Haskell. Because that would mean that the function can never return.
Rather, void is similar to the "unit type" (https://en.wikipedia.org/wiki/Unit_type) which does have a value. It's like an empty tuple. It contains no information other then "the function call has finished". (and of course in languages with exceptions, this means that no exception was thrown)
Otherwise, I like the article. More people should read and understand this way of thinking.