From: Brian Candler <lists@...>
Date: 2012-09-01T16:24:51+09:00
Subject: Re: Constructor or a Method

Rubyist Rohit wrote in post #1074150:
>    def name(=str)

I think you mean

def name=(str)

> (2) In case I ignore '=' in second method, will it work? Why '=' is
> necessary?

It's part of the method name.

obj.name = 123   # syntactic sugar, calls the name= method
obj.name=(123)   # same
obj.send(:name=,123)  # same

Note that in the first two cases, the value of the expression is forced 
to be the value of the argument (not the return value from the method).

>> class Foo; def name=(x); @name=x; return 999; end; end
=> nil
>> obj = Foo.new
=> #<Foo:0x1031a0438>
>> obj.name = 123
=> 123
>> obj.name=(456)
=> 456
>> obj.send(:name=,789)
=> 999
>> obj
=> #<Foo:0x1031a0438 @name=789>
>>

This is to avoid surprises when chaining together expressions which look 
like 'assignment'.

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