gaurav bagga wrote:
thanks all for the help
5 =MyNum.new
i wanted to do this just to have fun as most of the classes in ruby are open
String,Array... to be extended was trying same with Fixnum...... if
possible....
Ah. Well, you can touch Fixnum, but there's not much you can do with 5.
irb(main):001:0> class Fixnum; def squared; self * self end end
=> nil
irb(main):002:0> puts (1..10).map {|i| i.squared}.join(', ')
1, 4, 9, 16, 25, 36, 49, 64, 81, 100
=> nil
irb(main):003:0> def 5.foo; end
SyntaxError: compile error
(irb):3: parse error, unexpected tINTEGER
def 5.foo; end
^
(irb):3: parse error, unexpected kEND, expecting $
from (irb):3
irb(main):004:0> a = 5
=> 5
irb(main):005:0> def a.foo; end
TypeError: can't define singleton method "foo" for Fixnum
from (irb):5
irb(main):006:0> 5.instance_eval { @bar = 'quux' }
=> "quux"
irb(main):007:0> 5.instance_variable_get :@bar
=> "quux"
irb(main):008:0> 6.instance_eval { @bar }
=> nil
irb(main):009:0> "sdgsdg".object_id
=> 23037396
irb(main):010:0> "sdgsdg".object_id
=> 21070012
irb(main):011:0> "sdgsdg".object_id
=> 21055864
irb(main):012:0> 5.object_id
=> 11
irb(main):013:0> 5.object_id
=> 11
irb(main):014:0> 5.object_id
=> 11
In the last bit, notice how the String object_ids are all divisible by four. That's Ruby's cue that they're Real Objects, and object_id >> 2 is the start of the memory location they've been alloc'ed (IIRC). That 5 has an object_id not divisible by four is Ruby's cue that it's not a real object -- actually, that it's odd is Ruby's cue that its a Fixnum.
irb(main):015:0> (-1000..1000).all? {|i| i == i.object_id >> 1}
=> true
See, with Fixnums, no object is actually alloc'ed and pointed to. The pointer *is* an encoding of the number. Hence, no singleton methods for you.
Odd that you can define instance variables, but I'm sure if I bothered to read the Ruby source, it'd make perfect sense.
Devin
