std.xml should just go

[spir]

On 02/06/2011 10:28 PM, Jacob Carlborg wrote:
> On 2011-02-06 20:51, Walter Bright wrote:
>> Jacob Carlborg wrote:
>>> On 2011-02-04 08:34, Jonathan M Davis wrote:
>>>> Slices: just one more reason why D's arrays kick the pants of other
>>>> languages'
>>>> arrays...
>>>>
>>>> - Jonathan M Davis
>>>
>>> Ruby has array slices as well. A slice of an array refers to the
>>> original data just like in D. But on the other hand a new instance is
>>> created when making a slice (I assume, since everything is an object
>>> in Ruby).
>>>
>>
>> Can you use an array slice in ruby as an argument to any function that
>> takes a string?
>
> Since Ruby is a dynamically typed language you can pass in anything you want
> and relay on duck typing. The object passed in just have to support the slicing
> syntax/method.
>
> Hm, I just tried this and apparently a slice does NOT behave as in D. Modifying
> the slice does NOT modify the original array/string, I was completely sure it did.

I was wondering about this question by Walter. And actually, another answer 
would have surprised me, unless some magic would be in play, somewhat 
contradictory to Ruby's all-object motto.
I mean, modifying a slice (all or part of it) is replacing 1 or more 
element(s), each having their own address/identity, as /objects/ by themselves, 
not as variable values. Unlike in static languages (for non-referenced elements).
To get a similar behaviour, you'd need a double referencing/indirect, provided 
for instance by putting composite objects (or other collections, provided 
they're referenced) in an array, then changing slots of said objects (or 
elements of sub-collection). Then (if my reasoning is correct), modifying a 
slice would be seen from the original array.

Denis

PS: just tried in python [id() actualy returns address]:

l = [1,2,3]
s = l[1:2]
print l,s
print id(l[1]), id(s[0])
s[0] = 0
print l,s
print id(l[1]), id(s[0])
print

l = [1,[2],3]
s = l[1:2]
print l,s
print id(l[1]), id(s[0])
s[0][0] = 0
print l,s
print id(l[1]), id(s[0])

==>

spir at d:~/prog/python$ python "__essai__.py"
[1, 2, 3] [2]
169172356 169172356
[1, 2, 3] [0]
169172356 169172380

[1, [2], 3] [[2]]
3078505324 3078505324
[1, [0], 3] [[0]]
3078505324 3078505324

-- 
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