From: Brian Candler <B.Candler@...>
Date: 2007-03-11T00:01:15+09:00
Subject: Re: ruby / php operator differences.

On Sat, Mar 10, 2007 at 01:55:19PM +0900, Aaron Smith wrote:
> > It's the same in Ruby, except it goes further:
> > 
> > int |= 0x10000000
> > 
> > is short for
> > 
> > int = int | 0x10000000
> > 
> > is short for
> > 
> > int = int.|(0x10000000)      # infix operator is really method call on 
> > LHS
> > 
> > is short for
> > 
> > int = int.send(:|, 0x10000000)   # explicit method call by symbolic name
> 
> pretty flippin cool.
> 
> in this example:
> int = int.send(:|,0x1000000)
> 
> is it neccessary to have assignment portion? as in:
> int.send(:|,0x1000000), does this take out the need for (int=)

You don't need to make use of the return value. Every expression in Ruby
returns a value, but you can simply ignore it.

In your particular example, if you write

int = 4
int.send(:|, 0x10000000)

it's valid Ruby but isn't very useful, as it calculates a result and then
throws it away. But many methods do have side effects:

str = "hello"
str.send(:concat, " world")
puts str

Actually you'd normally write the middle line as

str.concat(" world")

or

str.concat " world"

or

str << " world"

(since the << infix operator expands to a << method call on str, and for
Strings the << method does the same as concat)

This stems from the fact that a String in Ruby is a mutable object (it can
change). Most objects are. However a few objects, in particular numbers and
symbols, are immutable. That is, you can't send a message to the number 5
telling it to change its value :-)

Regards,

Brian.