On 03/02/2016 12:00, fpc-pascal-requ...@lists.freepascal.org wrote:
Date: Tue, 2 Feb 2016 19:43:02 -0700 (MST)
From: silvioprog<silviop...@gmail.com>
>The problem with Iff() is:1) it either retains normal function behavior
>and thus has to evaluate both expressions (i.e. suboptimal performance and
>allowing side effects);
Well:
program Project1; function test1: integer; begin WriteLn('A');
Result := 10; end; function test2: integer; begin WriteLn('B');
Result := 20; end; function CommonFunc(A: Boolean; B, C: integer):
integer; begin if A then Result := B else Result := C;
end;var X: LongInt;begin X := IfThen(True, test1, test2); WriteLn(X);
WriteLn('----'); X := CommonFunc(True, test1, test2); WriteLn(X);
ReadLn;end.
Result:
A10----BA10
Holy sh*t, ça continue ! :)
Even if evaluation order will be assured and well documented, it doesn't
make sense!
Example :
x := iif(Obj = nil, 0, Obj.Value); // Seems OK when right-to-left and
stop on 'true' evalation
x := iif(Obj <> nil, Obj.Value, 0); // Raise access violation
Regards,
Serguei
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