Object#copy [rcr?]

[Ara.T.Howard]

can anyone think of a good reason NOT to have this feature?

class Object
def copy
Marshal::load(Marshal::dump(self))
end
end

i include this is nearly all of my own code and i know others do the same
quite often - why no method which does this?

-a
--
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| EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
| PHONE :: 303.497.6469
| ADDRESS :: E/GC2 325 Broadway, Boulder, CO 80305-3328
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| TRY :: for l in ruby perl;do $l -e "print \"\x3a\x2d\x29\x0a\"";done
===============================================================================

 

[Simon Strandgaard]

can anyone think of a good reason NOT to have this feature?

class Object
def copy
Marshal::load(Marshal::dump(self))
end
end

i include this is nearly all of my own code and i know others do the same
quite often - why no method which does this?

In the past I used the very same piece of code for deep copy.
Somewhere I changed my mind from liking it.. to not liking it.
I consider it kludgy to deepcopynig with help of serialize,
and its inefficient compared to custom #clone method.

Sorry.

 

[Yukihiro Matsumoto]

Hi,

In message "Object#copy [rcr?]"

|can anyone think of a good reason NOT to have this feature?
|
| class Object
| def copy
| Marshal::load(Marshal::dump(self))
| end
| end

I think deep copy should be implemented independently from
marshaling, which is inefficient and limited scheme for deep copy.
The only problem is that it's difficult to implement.

matz.

 

[Ara.T.Howard]

Hi,

In message "Object#copy [rcr?]"

|can anyone think of a good reason NOT to have this feature?
|
| class Object
| def copy
| Marshal::load(Marshal::dump(self))
| end
| end

I think deep copy should be implemented independently from
marshaling, which is inefficient and limited scheme for deep copy.
The only problem is that it's difficult to implement.

matz.

i see your point... perhaps an initial impl as in above, or even

class Object
def copy opts = {'levels'=>42}
Marshal::load(Marshal::dump(self))
end
end

where opts might later affect the semantics of #copy...

i guess i'm more interested in the __interface__ of copying: it would be nice
to be able to write code using

obj.copy

and nicer still if the impl got faster/better under the hood. it may not be
the best but, if "everyone's doing it"... ;-)


i understand the 'inefficient' bit above, but what exactly do you have in mind
by 'scheme'? other that 'how deep' i can't think of other things that might
affect a deep copy?

-a
--
===============================================================================
| EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
| PHONE :: 303.497.6469
| ADDRESS :: E/GC2 325 Broadway, Boulder, CO 80305-3328
| URL :: http://www.ngdc.noaa.gov/stp/
| "640K ought to be enough for anybody." - Bill Gates, 1981
===============================================================================

 

[Ara.T.Howard]

In the past I used the very same piece of code for deep copy.
Somewhere I changed my mind from liking it.. to not liking it.
I consider it kludgy to deepcopynig with help of serialize,
and its inefficient compared to custom #clone method.

Sorry.

you are right of course: i've written many a custom #clone methods and, for
that matter, many custom #dump methods as well - all in the name of speed. i
simply feel that the lack of a __builtin__ method to copy objects is one of
the very few things, like the lack of a detructor hook (Object#destroy ?),
that consistently suprises people and gives the feel of something obviously
'missing' from ruby. the impl is really quite moot - i'm simply advocating
something uniform in terms of __interface__ and Object#copy seems like quite a
reasonable one.

-a
--
===============================================================================
| EMAIL :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
| PHONE :: 303.497.6469
| ADDRESS :: E/GC2 325 Broadway, Boulder, CO 80305-3328
| URL :: http://www.ngdc.noaa.gov/stp/
| "640K ought to be enough for anybody." - Bill Gates, 1981
===============================================================================