Does Julia (v1.0) define or is there a convention for aliases for Union{T, Nothing} and Union{T, Missing}? For example const Maybe{T} = Union{T,Nothing} const Option{T} = Union{T, Missing} I am aware of wrapper type Some{T}, but that is used for the value nothing as opposed to Union{T,Nothing} wh…

Julia 2.0 reserves the right to go beyond any present (until then, you should be good with those three) :wink:

There are no such aliases predefined. Missing refers to a data element that may not be available, rather than an option. const Maybe{T} = Union{T, Nothing} (or similar) is used in Haskell

What would be a more suitable alias for Union{T, Missing}?

const Maybe{T} = Union{T, Nothing} const MaybeData{T} = Union{T, Missing}

@JeffreySarnoff So now we have Maybe{T} # value present or absent Some{T} # always a value including the value nothing MaybeData{T} # value present or missing DataValue{T} # ? The Julia manual has the section [ Frequently Asked Questions · The Julia Language ]. There it says “To represent …

No. I don’t what DataValue{T} is in the context of your question. That was added into QueryVerse long before the Missing and Nothing state-of-affairs had been settled. While I have no doubt it is useful for David … it is not used outside of that as far as I know. I was offering my opinion on how …

Sorry for nitpicking. Going from Julia v1.0 forward, is there a need to go beyond the following? Maybe{T} # value present or absent Some{T} # always a value including the value nothing MaybeData{T} # value present or missing

[image] JeffreySarnoff: (until then, you should be good with those three) I think that extensions don’t break 1.0, so in theory they would be OK. That said, I prefer Union{T, Missing} & similar. I am sure I would have a hard time remembering which of Maybe, Option, and other variants corresp…

I was responding to the question, not advocating syntax.

Aliases for Union{T, Nothing} and Union{T, Missing}?

New to Julia

stevengj September 24, 2018, 2:33am 6

I thought there was a proposal to parse T? as Union{T,Missing}, but I can’t find it.

Short type declarations (syntax sugar)?

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Aliases for Union{T, Nothing} and Union{T, Missing}?

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