CODEWITHSUNDEEP
juliakeyword-argument
Alexander Morley
Alexander Morley

Reputation: 4181

Allow function to ignore unsupported keyword arguments

Is there a nice way of allowing a function to ignore unsupported keyword arguments?

fopts = [:kw1]
opts = Dict(:kw1=>:symb1, :kw2=>:symb2)

function f(; kw1 = :symb)
    return kw1
end

f(;opts...) will throw a METHOD ERROR

I could wrap it in something like this, but then I still need to know which kwargs f will support?

function f2(fopts; kwargs)
    f(; Dict(key=>get(opts, key, 0) for key in fopts)...)
end

Am I missing a way around this. Not that fussed if there is a performance penalty as I imagine their may need to be some kind of look up. Is there a good way of interrogating what kwargs f accepts programatically?

Upvotes: 7

Views: 1021

Answers (2)

Alexander Morley
Alexander Morley

Reputation: 4181

Based on both @tim & @Gnimuc's comments one could define these two functions:

getkwargs(f) = methods(methods(f).mt.kwsorter).mt.defs.func.lambda_template.slotnames[4:end-4]

usesupportedkwargs2(f::Function, args...; kwargs...) = f(args...; Dict(key=>get(Dict(kwargs),key,0) for key in getkwargs(f))...)

But maybe there is a better way

Upvotes: 0

avysk
avysk

Reputation: 2035

Is this what you want?

function g(; kw1 = :a, kw2 = :b, _whatever...)
    return (kw1, kw2)
end

Now it works like this:

julia> g()
(:a,:b)

julia> g(kw1 = :c)
(:c,:b)

julia> g(kw2 = :d)
(:a,:d)

julia> g(kw2 = :e, kw1 = :f, kw3 = :boo)
(:f,:e)

Upvotes: 10

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