What does this code do?

New to Julia
1

I found this code recently. Does anybody know what it’s supposed to do?

(zip()...,)
2

Wow, interesting find. For folks who try to run this code: Ctrl-C is your friend.

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Good to know that this behavior is desired!

I spent some hours frustratedly trying to figure out why my program was just hanging, to find that it was because of this.

This is what I was doing. I swear I copypasted it from somewhere, but I can’t find it now. It converts Dicts to NamedTuples:

mydict = Dict(:a=>1, :b=>2)
nt = (; zip(zip(mydict...)...)...)

Works fine until mydict is empty. That part of the code was stable for a while and wasn’t part of the execution chain I was actively working on (it was part of a custom Base.show), so it took a while for me to suspect it. Of course, in other places I used the more terse and reasonable:

nt = (; mydict...)

but for show performance didn’t matter and it worked fine so I didn’t revisit it, until I ran into this edge case long after originally writing it.

It seems like a fun easter egg, something to give to people you don’t like so their programs nuke when they least expect it.

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I disagree and clearly at least one other person disagree @stevengj

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I probably deserved to be in debugging hell for writing such horrid code to begin with. Some form of cosmic coding karma.

I was thinking it could make a nice interview question to stump new hires. Is crash prevention really worth eliminating a possible interview question?

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You can just use the NamedTuple constructor:

julia> NamedTuple(Dict(:a => 1, :b => 2))
(a = 1, b = 2)

julia> NamedTuple(Dict())
NamedTuple()
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Wow, it looks like I even knew this already but I forgot! Funny how that works.

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Is this considered idiomatic?

for zip! in zip() zip, zip, zip, zip!, zip!, zip! end

or is this better:

for (zip!, zip!!) in zip(zip(), zip(zip())) zip, zip, zip, zip!, zip!, zip!, zip!!, zip!!, zip!! end

thinking of putting it into the catch branch of try...catch statements.