Why would you write this:
a = 1
b = 1
When you could write:
a = b = 1
A few reasons:
- Maybe you don’t know about this syntax
- Maybe you don’t mind writing out two lines
- Maybe you’re concerned about having two references to the same data, as explained in this StackOverflow post
I recently saw code that looked like this, which was disabling some loggers:
Something.logger = OtherThing.logger = nil
And I was kind of confused and amazed. I know about this multiple assigning syntax, but this looked kind of different. In the earlier example, we were assigning a value to a simple local variable, but in this case we were calling a setter method instead.
Something like:
class Dog
attr_reader :name, :family
def initialize(name)
@name = name
end
def family=(family_name)
@family = family_name
end
end
milo = Dog.new("Milo")
lola = Dog.new("Lola")
milo.family = lola.family = "The Jacobsons"
p [milo, lola]
# [#<Dog:0x007faf6115b158 @name="Milo", @family="The Jacobsons">, #<Dog:0x007faf6115b108 @name="Lola", @family="The Jacobsons">]
This works because Ruby gives you this syntactic sugar when you write a
something= method, it lets you put a space before the = when calling the
method. And that applies in this context too. Kind of neat.
