Arguments for Value types

[cscherrer]

Are Value types supposed to be able to take any Julia value as an argument?

julia> Val((2,42))
Val{(2, 42)}()

julia> Val(("ok","then"))
ERROR: TypeError: in Type, in parameter, expected Type, got Tuple{String,String}
Stacktrace:
 [1] Val(::Tuple{String,String}) at ./essentials.jl:683
 [2] top-level scope at none:0

[chakravala]

This has previously been discussed here

How to use a type wrapping a Symbol as a type parameter?

This question has some lengthy background where I explain my understanding of the problem. If you already know how the rules Julia uses for using values inside type parameters you can skip to the end: My understanding is that currently in Julia, if you want to use a value in a type parameter, that value must be a bit value satisfying isbits(v) == true. If that works, then for instance you can do julia> isbits(5) true julia> Val(5) Val{5}() julia> typeof(Val(5)) == Val{5} true This also wor…

[cscherrer]

Thanks, in reading the docs I had missed the part about the “isbits” constraint