In ruby, every object is reference type except for FixNum, NilClass,
TrueClass, FalseClass.
Let's consider FixNum only.
According to http://www.rubygarden.org/ruby?GCAndMemoryManagement, FixNum
takes only 4 bytes (on 32-bit machines).
Is it true?
If so, doesn't it have any other information except for the value itself?
How does ruby know that a FixNum is actually a FixNum instead of a reference
to an object when it doesn't have any information about the type?
I'm from C# background.
In C# (actually dotnet framework), values types are structures not just a
simple value.
only 31 bits. 1 bit is used as a flag to say "this is a ptr to object or it
is an immediate value stored in word"
-a
···
On Fri, 25 Jun 2004, Sam Sungshik Kong wrote:
Hello!
In ruby, every object is reference type except for FixNum, NilClass,
TrueClass, FalseClass.
Let's consider FixNum only.
According to http://www.rubygarden.org/ruby?GCAndMemoryManagement, FixNum
takes only 4 bytes (on 32-bit machines).
Is it true?
If so, doesn't it have any other information except for the value itself?
How does ruby know that a FixNum is actually a FixNum instead of a reference
to an object when it doesn't have any information about the type?
I'm from C# background.
In C# (actually dotnet framework), values types are structures not just a
simple value.
Could somebody resolve my confusion?
Thanks.
Sam
--
EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
PHONE :: 303.497.6469
A flower falls, even though we love it;
and a weed grows, even though we do not love it. --Dogen
According to http://www.rubygarden.org/ruby?GCAndMemoryManagement, FixNum
takes only 4 bytes (on 32-bit machines).
Is it true?
If so, doesn't it have any other information except for the value itself?
How does ruby know that a FixNum is actually a FixNum instead of a reference
to an object when it doesn't have any information about the type?
In Ruby, Fixnums have 31 bits; the missing bit (least significant one)
is used to mark it as a fixnum. This works because other objects will
be at even addresses.
I'm from C# background.
In C# (actually dotnet framework), values types are structures not just a
simple value.
Most objects in Ruby are indeed represented internally by structures;
take a look at ruby.h.
···
On Sat, Jun 26, 2004 at 02:38:05AM +0900, Sam Sungshik Kong wrote:
--
Running Debian GNU/Linux Sid (unstable)
batsman dot geo at yahoo dot com
We are using Linux daily to UP our productivity - so UP yours!
-- Adapted from Pat Paulsen by Joe Sloan
In ruby, every object is reference type except for FixNum, NilClass,
TrueClass, FalseClass.
Let's consider FixNum only.
According to http://www.rubygarden.org/ruby?GCAndMemoryManagement, FixNum
takes only 4 bytes (on 32-bit machines).
Is it true?
If so, doesn't it have any other information except for the value itself?
How does ruby know that a FixNum is actually a FixNum instead of a reference
to an object when it doesn't have any information about the type?
I'm from C# background.
In C# (actually dotnet framework), values types are structures not just a
simple value.
Could somebody resolve my confusion?
Ruby checks the least significant bit of the value. If this is set then the value is a direct value such as a fixnum, otherwise it's a reference to an object.
When Ruby is constructing a fixnum it left shifts the number one place then sets the LSB.
Wow, I'm so impressed that within 30 minutes I got 3 answers...
This group is very active, helpful, and enthusiastic.
Thanks all.
May I ask further questions related to the direct value type objects?
Now I understand how the FixNum is stored in the memory.
What about other value types - true, false, nil?
How are they distinguished from FixNum?
What are their sized?
Sorry to bother you guys with my beginner questions.
In ruby, every object is reference type except for FixNum, NilClass,
TrueClass, FalseClass.
Let's consider FixNum only.
According to http://www.rubygarden.org/ruby?GCAndMemoryManagement, FixNum
takes only 4 bytes (on 32-bit machines).
Is it true?
If so, doesn't it have any other information except for the value itself?
How does ruby know that a FixNum is actually a FixNum instead of a
reference
···
to an object when it doesn't have any information about the type?
I'm from C# background.
In C# (actually dotnet framework), values types are structures not just a
simple value.
