I was very happy to see Base.Fix2 since it saves typing for creating closures. Would it make sense to introduce a Fix1 that does the same, except for fixing the first argument?

On the other hand, https://github.com/JuliaLang/julia/pull/24990 would turn Fix2(f, x) into f(_, x) and the hypothetical Fix1(f, x) into f(x, _) which I personally like quite a lot. I guess another question would be whether you want the result of Fix1(f, x) to be y -> f(x, y) as above or the more g…

I don’t remember where I saw the discussion, but last I heard the core devs seemed quite resolved to support general currying with _ as in #24990, just not in 1.0. (I think I remember seeing 1.x, but I don’t want to put words in anyone’s mouth.) So, I have a pretty strong feeling that this is some…

I would distinguish having a parametric type that embodies partial application, eg Fix2 above, surface syntax for partial application, eg the proposed syntax with _. (1) exposes the components of what would be an otherwise opaque closure, and allows neat things like a show method for certai…

[image] Tamas_Papp: exposes the components of what would be an otherwise opaque closure, and allows neat things like a show method for certain function/argument combinations (this is what I want to use it for, actually) I guess I’m lacking in imagination. Could you give an example of what yo…

Imagine an interface with loglikelihood(model::SomeModel, parameters) where SomeModel is a user-defined type. Now with loglikelihood(model) = Fix1(loglikelihood, model) # hypothetical function Base.show(io::IO, l::Fix1{typeof(loglikelihood), M}) where M println(io, "log likelihood callable …

[image] Tamas_Papp: Would it make sense to introduce a Fix1 that does the same, except for fixing the first argument? Note that this is already planned. See e.g. replace `equalto` and `occursin` with curried `isequal`, `==`, and `in` by JeffBezanson · Pull Request #26436 · JuliaLang/julia · …

PR done: https://github.com/JuliaLang/julia/pull/26708

Would it make sense to go in the direction of C++ std::bind (see examples section)?

Fix1 (analogue of Base.Fix2)

Internals & Design

stevengj April 5, 2018, 2:49am 9

Note that this is already planned. See e.g. replace `equalto` and `occursin` with curried `isequal`, `==`, and `in` by JeffBezanson · Pull Request #26436 · JuliaLang/julia · GitHub

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Fix1 (analogue of Base.Fix2)

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