From: Ara.T.Howard@...
Date: 2004-10-03T13:54:57+09:00
Subject: Re: Just Found Integer()

On Sun, 3 Oct 2004, James Edward Gray II wrote:

>
> I'll confess to not being very "Duck Typing" aware, so I assume I'll
> understand the need for this method after I cover the chapter on that
> topic.  In the meantime though, can I just ask where this syntax came
> from???  I get that it's the resulting object name (I found Array(),
> Float() and String() too), but it still seemed pretty radical to me.

been there for a while:

   harp:~ > /usr/bin/ruby -v -e'p Integer(42)'
   ruby 1.6.8 (2002-12-24) [i386-linux-gnu]
   42

it's just a method that happens to also be a constant.

   harp:~ > /usr/bin/ruby -v -e'p Kernel.methods.grep(/Int/)'
   ruby 1.6.8 (2002-12-24) [i386-linux-gnu]
   ["Integer"]

think of it like Kernel.open being shorthand for File::open - it makes dirty
scipts feel short and sweet - but it's really a class method of File.  the
Integer and friend methods are better than, say String#to_i because

   harp:~ > /usr/bin/ruby -v -e'p "42abc".to_i'
   ruby 1.6.8 (2002-12-24) [i386-linux-gnu]
   42

   harp:~ > /usr/bin/ruby -v -e'p Integer("42abc")'
   ruby 1.6.8 (2002-12-24) [i386-linux-gnu]
   -e:1:in `Integer': invalid value for Integer: "42abc" (ArgumentError)
           from -e:1

i use them all the time because of this - if fact, my post from earlier today
has the Integer() contruct in it ;-)

kind regards.

-a
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