Re: Proposal: Auto-allocation of Indefinite Objects

["Randy Brukardt" <randy@rrsoftware.com>]

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:rhmd3m$1eql$2@gioia.aioe.org...
> On 20/08/2020 02:10, Randy Brukardt wrote:
>> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
>> news:rgr267$1o1n$1@gioia.aioe.org...
>>> No, from the abstraction point of view they do not. They indeed abstract
>>> the memory allocation aspect, but they do that at the cost of 
>>> *everything*
>>> else. Unbounded_String is no string anymore. Container is neither array
>>> nor record type. Unbounded_String must be converted forth and back. For
>>> containers I must use ugly hacks like iterators to make them resemble
>>> arrays and records introducing whole levels of complexity to fight 
>>> through
>>> every time the compiler or I miss something.
>>>
>>> In most cases I prefer to keep a clear array or record interface at the
>>> expense of manual memory management.
>>>
>>>> There's no free lunch.
>>>
>>> I think with a better type system there could be a whole banquet. (:-))
>>
>> Maybe. but IMHO a better type system would get rid of arrays and strings
>> altogether and only have containers/records of various sorts. The 
>> complexity
>> of having both solving the same problems (not very well in the case of
>> arrays/strings) doesn't buy much. I suspect that a user-defined "." as
>> you've proposed elsewhere would eliminate most of the rest of the 
>> problems
>> (and unify everything even further).
>
> But records and arrays are needed as building blocks of containers. How 
> would you get rid of them?

There's no reason that a compiler couldn't "build-in" a simple bounded 
vector container as the basic building block. We already do that for things 
like Ada.Exceptions, Unchecked_Conversion, and Unchecked_Deallocation, so 
it's no harder to do that for a vector. (Probably would need some sort of 
fixed vector for interfacing purposes as well, to deal with other language's 
and/or system's memory layout.)

One could do something similar for records, although I would probably leave 
them as in Ada and just allow user-definition of "." (via a getter/setter 
pair).

                                 Randy.