Should "a,b = x,y = 1,2" give an error?

ruby-talk
1

This

    a,b = x,y = 1,2

give me a
"NameError: undefined local variable or method `x' for main:Object",
yet

   a = x = 1 ; b = y = 2;

or

   a,b = (x,y = 1,2)

seem to work fine. It doesn't really bother me since the
workarounds are easy, but the first one looks cleaner to me.
Would this still be an error in Ruby2?

2

irb(main):001:0> a = b = x = y = 0
=> 0
irb(main):002:0> a,b = x,y = 1,2
=> [0, 1, 2]

Doesn't work without seeing previous assignments to the variables
involved. Maybe working as designed? Don't know.

Jim

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···

On Fri, 4 Nov 2005 06:59:31 +0900, Ron M <rm_rails@cheapcomplexdevices.com> wrote:

This

   a,b = x,y = 1,2

give me a
"NameError: undefined local variable or method `x' for main:Object",
yet

3

Hi --

This

  a,b = x,y = 1,2

give me a
"NameError: undefined local variable or method `x' for main:Object",
yet

a = x = 1 ; b = y = 2;

or

a,b = (x,y = 1,2)

seem to work fine. It doesn't really bother me since the
workarounds are easy, but the first one looks cleaner to me.

It's a bit over-cleaned in this case :slight_smile: It's parsed as:

   (a,b) = x,(y=1),2

Would this still be an error in Ruby2?

Matz has discussed possibly changing multiple assignment, but I think
in a case like this the rules would still be the same. That's
actually good -- we want y=1 to mean y=1 :slight_smile:

David

···

On Fri, 4 Nov 2005, Ron M wrote:

--
David A. Black
dblack@wobblini.net