Add Row#each_pair

[zverok]

Reason: Row tries to quack more-or-less like Hash, and Hash has #each_pair. A practical example where it matters:

csv = CSV.parse('Bob,100', headers: %i[name salary])
OpenStruct.new(csv.first)
# NoMethodError: undefined method `each_pair' for #<CSV::Row name:"Bob" salary:"100">

# After this patch:
OpenStruct.new(csv.first)
#=> #<OpenStruct name="Bob", salary="100">

[kou]

Do you want to try adding a test?

[zverok]

Thought about it, but I am not sure what is an appropriate amount of testing. It is just an alias, so do you expect me to copy-paste of tests of #each, or just literally test "the alias, named this, exists"?

[kou]

This change isn't so simple.

What is the expected behavior of the following case?

require "csv"
csv = CSV.parse('Bob,100', headers: %i[name salary])
p csv.first.each_pair.to_a
# /tmp/a.rb:3:in `<main>': undefined method `each_pair' for ["Bob", "100"]:Array (NoMethodError)

[zverok]

What is the expected behavior of the following case?

On my branch:

csv.first.each_pair.to_a
# => [[:name, "Bob"], [:salary, "100"]]

Is there some problem?..

[kou]

Ah, sorry. I pasted wrong code:

require "csv"
csv = CSV.parse('Bob,100')
p csv.first.each_pair.to_a 

[kou]

Ah. it's not related with this change.
It's my fault.