Feature #17327: The Queue constructor should take an initial set of items

• Status: Closed
• Assignee: ko1 (Koichi Sasada)
• Target version: -

[chrisseaton (Chris Seaton)]

I often create a Queue and then process it with a set of concurrent workers in threads. I end up writing:

q = Queue.new
worklist.each do |work|
  q.push work
end

I'd rather be able to write

q = Queue.new(*worklist)

[chrisseaton (Chris Seaton)]

https://github.com/ruby/ruby/pull/3768

[ioquatix (Samuel Williams)]

What about a way to bulk add items, e.g. q.concat or whatever is the same for Array, and maybe it would be best to have the first argument as an array, e.g. Queue.new(worklist)? I think it's more expensive to expand it in CRuby when you write *worklist.

Internally, this might still be adding one item at a time, in order to invoke the right "wakeup" machinery.

[chrisseaton (Chris Seaton)]

I'm not worried about Queue.new(worklist) or Queue.new(*worklist), so that's fine if more people feel that way. I think the key thing is conciseness in text source code, and also avoiding needing to synchronise while adding each individual item.

[ioquatix (Samuel Williams)]

That all makes sense to me.

[byroot (Jean Boussier)]

I agree that the constructor should take an enumerable rather than variadic arguments, as it would be consistent with Set.new([1, 2, 3]), and Array.new([1, 2, 3])

[ufuk (Ufuk Kayserilioglu)]

Agreed with @byroot (Jean Boussier) (actually I was going to note the same, he beat me to it).

I would also like to note that different from Set, for example, the order of items in the supplied parameter matters in the Queue case. Even though the expected outcome is for the items to be pushed to the Queue in given order, it might still be a good idea to explicitly call that out in the method documentation.

[chrisseaton (Chris Seaton)]

I updated to take a single array rather than a variable number of arguments.

I had two choices for how to do this - Set takes an Enumerable, using each to access items, and Array takes another Array, using #to_ary if needed.

I went with the same as what Array does, because both Array and Queue are core libraries, where Set is a standard library.

[matz (Yukihiro Matsumoto)]

I accept the idea. Take Enumerable as initial values.

Matz.

[ko1 (Koichi Sasada)]

• Assignee set to ko1 (Koichi Sasada)

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset git|1f0e0dfb228fd14b3f6687539ba274ba6a2d1643.

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Thread::Queue.new should accept an Enumerable [Feature #17327]

Enumerable implements #to_a but not #to_array.