From: Dave B <redmine@...>
Date: 2009-12-21T15:48:19+09:00
Subject: [ruby-core:27263] [Bug #2422] splat operator fails on array of 1 element

Issue #2422 has been updated by Dave B.



Tanaka Akira wrote:
> 2009/12/21 katz bo <redmine@ruby-lang.org>:
>> I personally think *[1, 2, 3] should be always unpacked first.
>>
>> a = *[1, 2, 3] #(unpack Array due to *) should be equal to:
>> a = 1, 2, 3    #(as Ruby is very smart) is equal to: (this is really the tricky part)
>> *a = 1, 2, 3   #which packs 1, 2, 3 into Array a. Hence is equal to
>> a = [1, 2, 3]
>>
>> a = *[1] #(unpack Array due to *) should be equal to:
>> a = 1    #(again, Ruby is smart it won't read this as *a = 1)
>
> Your way cannot interpret a = *[].
>
> a = *[]
> a =
>
> It is not a valid Ruby statement.

I would expect to see the value of the first element in the empty array
as 1.8.6 provides ...

puts 'ruby %s (%s) [%s]' % [RUBY_VERSION, RUBY_RELEASE_DATE, RUBY_PLATFORM]

a = *[]
p a

a = [][0]
p a

# ruby 1.8.6 (2008-08-11) [i386-mswin32]
# nil
# nil


# ruby 1.9.2 (2009-05-19) [i386-mswin32_90]
# []
# nil


I understood your last reply to me about "a, =" in multiple assignment
with a single RHS but, to me, "a = 1" is multiple assignment with
balanced (single) LHS/RHS.

Producing an empty array from a splatted empty array seems unproductive. ;)


daz

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