Is it possible to check if a function has been called with a keyword argument explicitly?

General Usage
1

Is there a way to determine if a keyword argument with a default value has been explicitly given or the default has been used ?

function foo(;karg1::Int64=3)
    # if foo has been called with karg1 explicitly then... else...
end

I know I can use kwargs... and then check the dictionary, but my actual function has several default keyword arguments and I am interested in checking just one…

(I bet “no” but… never know!)

2

If I’m getting the jist of what you want. I think multiple dispatch with varied input defined as different functions should meet your requirements.

3

My suggestion here would allow this, but could be considered to make your function “messier”.

function A(x; karg1=nothing)
    if isnothing(karg1)
        karg1 = 3
    else
        # karg1 was explicitly given
    end
    # rest of function
end

And you could even disambiguate whether the keyword argument was explicitly given with the default value, e.g.

function A(x; karg1=nothing)
    if isnothing(karg1)
        karg1 = 3
    elseif karg1 == 3
        # karg1 was explicitly given as the default value
    end
    # rest of function
end
4

yep, that’s exactly the “solution” I ended up using…