[fpc-devel] += with properties

michael.vancanneyt at wisa.be michael.vancanneyt at wisa.be
Wed Jan 12 17:01:16 CET 2011

On Wed, 12 Jan 2011, Michael Schnell wrote:

> On 01/12/2011 04:48 PM, Alexander Klenin wrote:
>> Blindly replacing "a += b" with "a := a + b" may lead to a semantic change
>> if "a" is an expression with side-effects.
>> Nevertheless, I do think that implementing += for properties is a good 
>> idea,
>> but unfortunately FPC developers disagree.
> I do see that also properties could show site effects when used in a += 
> expression, as they are accessed twice. But is this (in nearly all cases) not 
> exactly what the user would expect ?

Most of the time, yes. But there are some subtleties with interfaces and
reference counting, which could bite you in the leg.

(as they already have for some people).


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