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Type of union of disjunct functions?
Where's the contravariance?Are there type signatures which Haskell can't verify?Type theory: type kindsDoes C++11 support types recursion in templates?One type vs. multiple typesRepresenting a fixpoint in a head-normal lambda calculus ASTWhat's the difference between parametric polymorphism and higher-kinded types?Proving commutativity of type level addition of natural numbersA category of type-changing substitutionsWhat is positivity checking?
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Given two functions:
f :: EvenInteger -> 0
g :: OddInteger -> 1
consider the function
h = (x :: Integer) =>
if(x is even)return f(x);
return g(x);
What the smallest type T such that
h :: T
I was thinking that it is simply
h :: (typeof f) & (typeof g)
But then I would also think that a function call distributes over conjunction i.e., that
x :: EvenInteger
h(x) :: (typeof f(x)) & (typeof g(x))
which begs another question:
What is
(OddInteger -> 1)(EvenInteger)
type-theory
add a comment |
Given two functions:
f :: EvenInteger -> 0
g :: OddInteger -> 1
consider the function
h = (x :: Integer) =>
if(x is even)return f(x);
return g(x);
What the smallest type T such that
h :: T
I was thinking that it is simply
h :: (typeof f) & (typeof g)
But then I would also think that a function call distributes over conjunction i.e., that
x :: EvenInteger
h(x) :: (typeof f(x)) & (typeof g(x))
which begs another question:
What is
(OddInteger -> 1)(EvenInteger)
type-theory
add a comment |
Given two functions:
f :: EvenInteger -> 0
g :: OddInteger -> 1
consider the function
h = (x :: Integer) =>
if(x is even)return f(x);
return g(x);
What the smallest type T such that
h :: T
I was thinking that it is simply
h :: (typeof f) & (typeof g)
But then I would also think that a function call distributes over conjunction i.e., that
x :: EvenInteger
h(x) :: (typeof f(x)) & (typeof g(x))
which begs another question:
What is
(OddInteger -> 1)(EvenInteger)
type-theory
Given two functions:
f :: EvenInteger -> 0
g :: OddInteger -> 1
consider the function
h = (x :: Integer) =>
if(x is even)return f(x);
return g(x);
What the smallest type T such that
h :: T
I was thinking that it is simply
h :: (typeof f) & (typeof g)
But then I would also think that a function call distributes over conjunction i.e., that
x :: EvenInteger
h(x) :: (typeof f(x)) & (typeof g(x))
which begs another question:
What is
(OddInteger -> 1)(EvenInteger)
type-theory
type-theory
edited Mar 23 at 21:44
Ray Toal
68k11128185
68k11128185
asked Mar 23 at 21:39
AdamAdam
1,067314
1,067314
add a comment |
add a comment |
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