push! on Dicts

[Keno]

Now that we have the nice syntax for pairs, I think it would be convenient for

a = Dict()
push!(a,1=>2)

to work. At the moment we have to use

push!(a,1,2)

which probably should be reflected in the docs for push!, which are right now:

  push!(collection, items...) → collection

  Insert items at the end of collection.

  push!([1,2,3], 4) == [1,2,3,4]

[ivarne]

+1
If push!(a,1,2) is a varargs function to push arbitrary number of items to the collection, the current definition for Associative is inconsistent. We should either remove the varargs fallback, or require push!(a,(1,2)), push!(a, [1,2]) or push!(a, 1=>2).

[johnmyleswhite]

+1

[JeffBezanson]

Let's definitely deprecate push!(t::Associative, key, v), use push!(dict, 1=>2) instead, and continue to allow pushing several items using varargs.

[ivarne]

I made a half attempt at fixing this, and I'm somewhat disappointed that it didn't break any tests. I don't have time for more today, but anyone is welcome to git checkout in/issue-9295 and add proper testing of the new push! method, if they can beat me to it.

[bicycle1885]

@ivarne
I cherry-picked your half fix and added varargs support and some tests.
But it breaks very rare (I hope) backward compatibility: push!ing a pair of Pair key and Pair value.

One workaround would be using explicit type parameters:

push!{K,V}(::Associative{K,V}, ::Pair{K,V}, ::Pair{K,V})

but this will change the semantic of push!.