Re: a = Dog.new # a is not a pointer and not a reference?


On Sep 29, 2007, at 10:17 PM, SpringFlowers AutumnMoon wrote:

Morton Goldberg wrote:
On Sep 29, 2007, at 8:18 PM, SpringFlowers AutumnMoon wrote:

Come to think about it, a pointer is very clear cut... an alias is
very
clear cut. but when it is "reference", then you have to think whether
it is the pointer behavior or the alias behavior.

No, you do not. Ruby has it own semantics, which do not correspond
with the semantics of C or C++. Trying to impose the semantics of
other languages onto Ruby isn't going to work. It's best to drop such
baggage and start fresh.

hm,... but is there a problem to think of reference in Ruby as a
"pointer"? will that cause any trouble? I only see that a.value is
not the same as C and C++ would use a->value, but in Ruby we use the "."
to replace the "->" and that's it. Will there be further trouble or
discrepancy to think of Ruby reference as a pointer?

Well, your assertion that a.value is the equivalent of a->value is a good example of getting into trouble by equating a reference to a pointer. The expression a.value is a method call, not a value fetch. For a.value to work, the object referred by a has have a method called 'value', either an instance method or singleton method, in its extended object table. If it does, the method is executed and some object is returned. That's not at all what a->value does in C.

Regards, Morton

.

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