unit-type Questions
1
Solved
As per the documentation of unit type (), It implements the Extend trait.
fn extend<T>(&mut self, iter: T)
where
T: IntoIterator<Item = ()>,
Extends a collection with the conte...
4
Solved
Rust has the unit type, (), a type with a single zero-size value. The value of this unit type is also specified using ().
What is the purpose of the unit type and its value? Is it a mechanism to av...
3
Solved
This question is not about C#/F# compatibility as in this one.
I'd like to know the proper way to implement a type like F# Unit in place of using void.
Obviously I'll discard this result and I'll...
Aldred asked 16/6, 2015 at 6:18
4
Solved
I read this MSDN article:
Unit Type (F#)
...The unit type is a type that indicates the absence of a specific
value; the unit type has only a single value, which acts as a
placeholder when no ...
Gallfly asked 20/12, 2013 at 13:37
2
Solved
I know that the C++ standard library has a unit type - I've seen it before - but I can't remember what it's called. It starts with an "m", I know that much, and it is equivalent to this definition:...
1
Just as the title says: what guarantees are there for a Haskell function returning unit to be evaluated? One would think that there is no need to run any kind of evaluation in such a case, the comp...
Roulette asked 27/11, 2019 at 13:46
2
Solved
I found four different ways to create a struct with no data:
struct A{} // empty struct / empty braced struct
struct B(); // empty tuple struct
struct C(()); // unit-valued tuple struct
struct...
Flathead asked 3/5, 2018 at 19:31
4
Solved
This memoize function fails on any functions of type () -> 'a at runtime with a Null-Argument-Exception.
let memoize f =
let cache = System.Collections.Generic.Dictionary()
fun x ->
if ca...
1
I deliberately added x to the end of this function
let myMax x y =
if x > y then x else y
x
I was expecting that x and y arguments are still of ‘a type, but I get this signature instead:
m...
4
Solved
Imagine the following interface in C#:
interface IFoo {
void Bar();
}
How can I implement this in F#? All the examples I've found during 30 minutes of searching online show only examples that h...
Borlase asked 18/6, 2010 at 6:25
1
Solved
I found out they are mean an empty tuple. However, are they also used as a convention by Elm programmers to mean "value can be ignored"?
is13 : Int -> Result String ()
is13 code =
if code == ...
Urson asked 27/11, 2015 at 1:29
2
Solved
If I define a function:
fn f() -> Result<(), E> {
// How to return Ok()?
}
How can I return the Ok in std::result with the unit type ()?
2
Solved
Consider this interface:
type A<'a> =
abstract X : 'a
Let's try to implement it with int as a generic argument:
{ new A<int> with member this.X = 5 } // all is well
Now, let's tr...
6
Solved
I'm reading Learn You a Haskell, and in the monad chapters, it seems to me that () is being treated as a sort of "null" for every type. When I check the type of () in GHCi, I get
>> :t ()
()...
3
Solved
How can i return unit from an expression in f#? For example:
let readInt =
let str = Console.ReadLine()
let (succ, num) = Int32.TryParse(str)
match succ with
| true -> Some(num)
| _ -> ...
4
Solved
I just started to learn F#. The book uses the following notation:
let name() = 3
name()
what that differs from this:
let name = 3
name
?
Meg asked 26/7, 2013 at 0:22
1
Solved
Suppose I've defined the following interface in F#:
type IFoo<'T> =
abstract member DoStuff : 'T -> unit
If I implement this in C# I need the method signature to be:
public void DoSt...
1
Solved
Consider this code:
var unit: Unit = null
unit: Unit = ()
a) Why am I allowed to assign null to a value class? (see §12.2.3)
b) Why does the null get converted to ()?
3
Solved
I have a problem when returning values in complex functions. Examples are always better:
Consider the following function:
let myf (mypar: int) =
mypar + 1
Well no probel here, this function is...
Vesting asked 21/2, 2011 at 16:25
1
Solved
Does anyone know why this fails to compile?
type MyInterface<'input, 'output> =
abstract member MyFun: 'input -> 'output
type MyClass() =
interface MyInterface<string, unit> wi...
3
I'm trying to learn a little of the mindset of functional programming in F#, so any tips are appreciated. Right now I'm making a simple recursive function which takes a list and returns the i:th el...
Emmaemmalee asked 12/11, 2010 at 14:13
3
Solved
I've recently started playing with Scala (2.8) and noticed the I can write the following code (in the Scala Interpreter):
scala> var x : Unit = 10
x : Unit = ()
It's not obvious what's going ...
2
Solved
Quite new to functional languages, but I'm maintaining someone else's code with a lot of F#. Can anyone offer some insight into this?
let mtvCap = Rendering.MTViewerCapture(mtViewer)
mtvCap.GetC...
2
Solved
When thinking in a functional mindset, given that functions are supposed to be pure, one can conclude any function with no arguments is basically just a value.
However, reallity gets in the way, an...
Vanscoy asked 9/5, 2010 at 12:55
2
Solved
How can I write a no-op statement in F#?
Specifically, how can I improve the second clause of the following match statement:
match list with
| [] -> printfn "Empty!"
| _ -> ignore 0
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