Trying to wrap my mind around singleton types to see if they might be
useful for something I'm working on, but running into some confusion. Here
is an example that I started working with:
julia> type BadInt
end
julia> import Base.+
julia> +(x::BadInt, y::Int64) = x - y
+ (generic function with 172 methods)
julia> BadInt() = 2
BadInt
julia> BadInt + 2
ERROR: MethodError: `+` has no method matching +(::Type{BadInt}, ::Int64)
Closest candidates are:
+(::Any, ::Any, ::Any, ::Any...)
+(::Int64, ::Int64)
+(::Complex{Bool}, ::Real)
...
As I understand, a singleton type can only take on a single value. What's
the utility in supporting this?
