[fpc-devel] Incomplete docs on operator precedence / Question about actual precedence

[Michael Van Canneyt]

On Mon, 3 Feb 2014, Sven Barth wrote:

> Am 03.02.2014 12:04, schrieb Michael Van Canneyt:
>> 
>> 
>> On Mon, 3 Feb 2014, Sven Barth wrote:
>> 
>>> Am 03.02.2014 08:58, schrieb Michael Van Canneyt:
>>>> As for unary minus: this is the same as a binary minus in arithmatic 
>>>> expressions.
>>> 
>>> Not quite. Take this example:
>>> === output end ===
>>> 
>>> So unary minus (and also unary plus which is a valid operator as well!) 
>>> binds stronger than multiplication.
>> 
>> Then that is an anomaly introduced by operator overloading.
>> 
>> In math, -2^2 = -4
> Yes and the same is true in FPC with operator overloading. If you add a ** 
> operator overload (which uses Trunc(Power(aLeft.i, aRight.i)) ) and have this 
> expression: -t1 ** t2 with t1.i = 2 and t2.i = 2 the result will be -4 as 
> well.
>
> Please keep in mind that -2^2 is (-2) * (-2).

? Not in math:

-2^2 = - (2^2)

Michael.