From: Quintus <quintus@...>
Date: 2012-06-08T22:08:07+09:00
Subject: Re: Inexplicable Argument Error

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Am 08.06.2012 10:57, schrieb Jan E.:
> Hi,
> 
> You actually *can* assign multiple values, if you use assignment
> syntax:
> 
> my_object.val = 1, 2
> 
> This will wrap 1 and 2 into an array and assign it to the single 
> parameter of the val= method. Not exactly what you want, but it
> works just as well.

Not necessarily. The array is only assigned to the parameter if Ruby
doesn’t find anything else to assign to.

# ruby -v: ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-linux]
irb(main):001:0> class Foo
irb(main):002:1> def foo=(val)
irb(main):003:2> p val
irb(main):004:2> end
irb(main):005:1> end
=> nil
irb(main):006:0> f = Foo.new
=> #<Foo:0x00000002704430>
irb(main):007:0> f.foo = 1, 2
[1, 2]
=> [1, 2]
irb(main):008:0> x, f.foo = 1, 2  #<----
2
=> [1, 2]
irb(main):009:0> x
=> 1
irb(main):010:0>

This way, x gets the 1 and the foo= assignment method gets the 2.

> Anyway, I think you shouldn't use = methods the way you do. They
> are not meant to be called directly and used as normal methods.
> Their only purpose is to fake the attribute syntax of classical
> object oriented languages.

Agreed.

Valete,
Marvin
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