From: "Matthew, Graeme" <Graeme.Matthew@...>
Date: 2002-09-19T15:26:52+09:00
Subject: If Statement Help and param passing

Thanks Ryan, no wonder I couldnt find any doco :-) doh ! , one more for the
day

I have noticed that some params in methods / function are passed as follows:

object.method(value, *data)

is the * character serving a purpose here, eg passing by value rather than
reference ?


Thanks for all your help ...


Graeme Matthew
Analyst Programmer
Mercer Investment Consulting
Level 29, 101 Collins Street, Melbourne, VIC, 3001, Australia
Tel  - 61 3 9245 5352 Fax - 61 3 9245 5330
visit http://www.merceric.com


-----Original Message-----
From: Ryan King [mailto:rking@panoptic.com]
Sent: Thursday, 19 September 2002 16:22
To: ruby-talk@ruby-lang.org
Subject: Re: If Statement Help


On 2002.09.19, Matthew, Graeme <Graeme.Matthew@mercer.com> wrote:
> if File.name?
> 
> Can someone please explain the ? usage as I have searched all over the
> Pragmatic Programmer pages with no answer. 

That's just a part of the method name.  Run "irb" and paste this
into it:

class Monkey
  def hasFleas?
    true
  end
end
class Rking
  def hasFleas?
    false
  end
end
Monkey.new.hasFleas?
Rking.new.hasFleas?

You will find that Monkeys have fleas while Rking's decidedly do
NOT.

Anyway, the point is: Putting a question mark at the end of a
method name is a custom to imply that the method returns a
boolean.

 - Ryan
__


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