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From: Bart <bc@freeuk.com>
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Subject: =?UTF-8?Q?Re=3A_technology_discussion_=E2=86=92_does_the_world_need?=
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Date: Fri, 16 Aug 2024 15:19:38 +0100
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On 16/08/2024 01:08, Ben Bacarisse wrote:
> Bart <bc@freeuk.com> writes:
> 
>> On 15/08/2024 15:33, Ben Bacarisse wrote:
>>> Bart <bc@freeuk.com> writes:
>>>
>>>> On 15/08/2024 09:43, Tim Rentsch wrote:
>>>>> Bart <bc@freeuk.com> writes:
>>
>>>>>                            C call-by-value         call-by-reference
>>>>>                            ===============         =================
>>>>>      at call:
>>>>>
>>>>>        (array argument)    F(A)                    H(A)
>>>>>
>>>>>        (pointer argument)  F(p)                    (disallowed)
>>>>
>>>> My posts were about passing *arrays* and the fact that C's pass-by-value
>>>> was remarkably similar to pass-by-reference.
>>> Which is why, presumably, you didn't show the differences.  Your
>>> post was all polemic not part of a collegiate discussion of the
>>> similarities and differences.
>>>
>>>> However your entry for pointers is not correct:
>>> No, the entry is correct.  H(p) would be (is?) disallowed when H's
>>> parameter is a reference to an array.
>>
>> Sorry, what language does the right-hand column pertain to? /Any/ language
>> that has call-by-reference, or Tim's hypthetical language?
> 
> Tim said that case was "disallowed".  You call that an error on his
> part.  What language did you have in mind that permits such a gross
> warping of types?  I would describe /any/ language that allowed it as
> having a design error.

You or he would have to go into more detail, such as an actual example, 
to demonstrate whatever it is that you think is wrong about passing a 
pointer argument by-reference.

I assume here that the language in the right column is not C.

> 
>> Or any that could be used to prove him right?
>>
>> In general there is no reason, in a language with true call-by-reference,
>> why any parameter type T (which has the form U*, a pointer to anything),
>> cannot be passed by reference. It doesn't matter whether U is an array type
>> or not.
> 
> I can't unravel this.  Take, as a concrete example, C++.  You can't pass
> a pointer to function that takes an array passed by reference.  You can,
> of course, pass a pointer by reference, but that is neither here nor
> there.

OK. So why do you agree with this:

 >>>>>                            C call-by-value         call-by-reference
 >>>>>                            ===============         =================
 >>>>>        (pointer argument)  F(p)                    (disallowed)

What is 'pointer argument' here?