From: Phrogz <gavin@...>
Date: 2007-01-26T09:20:12+09:00
Subject: Re: Ruby language question


On Jan 25, 5:02 pm, Neville Franks <s...@surfulater.com> wrote:
>      def size=(val)   # what does this mean
>        @size = val
>      end

Methods whose names end in an '=' character can be called with a space
between the method name and the '=' character. Combined with the
ability to leave parentheses off a method call, it looks very much like
you're assigning to an attribute, when you're calling a method:

irb(main):001:0> class Foo; def a=( b ); p b; end; end
=> nil
irb(main):002:0> f = Foo.new
=> #<Foo:0x52f468>
irb(main):003:0> f.a=(1)
1
=> 1
irb(main):004:0> f.a =( 2 )
2
=> 2
irb(main):005:0> f.a= 3
3
=> 3
irb(main):006:0> f.a = 4
4
=> 4

One thing to note - the single argument passed to the function under
this syntax is also always the return value. (In the above, the #p
method returns nil, but you can see that the return value of the method
is the 'rvalue' for the 'assignment'.