struct Union(*T)
Overview
A union type represents the possibility of a variable or an expression having more than one possible type at compile time.
When invoking a method on a union type, the language checks that the
method exists and can be resolved (typed) for each type in the union.
For this reason, adding instance methods to Union
makes no sense and
has no effect. However, adding class method to Union
is possible
and can be useful. One example is parsing JSON
into one of many
possible types.
Union is special in that it is a generic type but instantiating it might not return a union type:
Union(Int32 | String) # => (Int32 | String)
Union(Int32) # => Int32
Union(Int32, Int32, Int32) # => Int32
Defined in:
ssz/codec.crssz/hash_tree_root.cr
Class Method Summary
- .hash_tree_root(value : self) : Bytes
- .ssz_basic? : Bool
- .ssz_decode(io : IO, size : Int32 = 0)
- .ssz_encode(io : IO, value : self)
- .ssz_encode(value : self) : Bytes
- .ssz_fixed? : Bool
- .ssz_size(value : self) : Int32
- .ssz_type_index(value : self) : SSZ::Offset
- .ssz_variable? : Bool
Instance methods inherited from class Object
ssz_basic? : Bool
ssz_basic?,
ssz_encode(io : IO)ssz_encode : Bytes ssz_encode, ssz_fixed? : Bool ssz_fixed?, ssz_size : Int32 ssz_size, ssz_variable? : Bool ssz_variable?
Class methods inherited from class Object
ssz_basic? : Bool
ssz_basic?,
ssz_decode(io : IO, size : Int32 = 0)ssz_decode(bytes : Bytes) ssz_decode, ssz_fixed? : Bool ssz_fixed?, ssz_variable? : Bool ssz_variable?