CODEWITHSUNDEEP
julia
juliohm
juliohm

Reputation: 3789

How to define method for all parametric subtypes of an abstract type in Julia?

Suppose I have an abstract base class:

abstract type B end

and many concrete subtypes:

struct C1{T,V} <: B end
struct C2{T,V} <: B end
...

how to define a method for all subtypes in an elegant way?

result_type(::C1{T,V}) = T
result_type(::C2{T,V}) = T
...

The subtypes function doesn't seem to contain the parameter types T and V that I am trying to query, is there a clean solution?

for C in subtypes(B)
    # how to define result_type for C?
end

Upvotes: 1

Views: 287

Answers (1)

Chris Rackauckas
Chris Rackauckas

Reputation: 19162

Just add the type parameter to the abstract type.

abstract type B{T,V} end
struct C1{T,V} <: B{T,V} end
struct C2{T,V} <: B{T,V} end
result_type(::B{T,V}) where {T,V} = T

Upvotes: 5

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