[fpc-pascal] Feature announcement: Dynamic array extensions

[Mark Morgan Lloyd]

On 02/06/18 08:00, Ryan Joseph wrote:
>> On Jun 2, 2018, at 2:42 PM, Sven Barth via fpc-pascal <fpc-pascal at lists.freepascal.org> wrote:> > It wasn't me who implemented that part. I personally had planned to do it with a warning for existing overloads, but Florian beat me to it and implemented it this way. Though when asked by me he did say that we'll wait and see if people complain... So *maybe* we'll change this.>
> btw why can’t there be both? You can have multiple + operators for any given dynamic array type can’t you?
> type	TArrayOfInteger = array of integer;
> operator + (left: TArrayOfInteger; right: integer): TArrayOfInteger;var	i: integer;begin	for i := 0 to high(left) do		left[i] += 1;end;
> operator + (left: TArrayOfInteger; right: TArrayOfInteger): TArrayOfInteger;begin	result := Concat(left, right);end;

Agreed, both are extremely useful and have an intuitively unambiguous 
meaning (unlike - which can be useful but doesn't have an unambiguous 
meaning).

However as Dennis points out + is also essential for vector operations. 
Perhaps either leaving it to the programmer to define what's needed 
would be the best approach, or alternatively splitting dynamic arrays 
into mathematical vectors and non-mathematical collections. Or relaxing 
the requirement that only predefined operators can be redefined, so that 
something like _ could be used for concatenation.

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]