[Libreoffice] [REVIEW][3-4] date change regression fdo#44385

[Noel Power]

Hi Eike,

On 16/01/12 13:01, Eike Rathke wrote:
> Hi Noel, On Friday, 2012-01-13 09:51:33 +0000, Noel Power wrote:
>> this change ( the variant ) is what is on master, here the intention 
>> is as Andrew pointed out ( in a previous mail discussing the 
>> regression ) to allow operations on date types return dates ( 
>> regardless of the operation ) which seems reasonable. 
> Not every operation on date types should return a date,
I have to admit I was swayed by Andrew's point that letting the 
operations just return Dates seems more consistent.Also it would seem to 
me subtraction should at least mirror the behaviour of addition.

e.g.
     something = date() + 1 ' something becomes a variant date ( 1 day 
into the future )
     something = date() - 1 ' something becomes a variant date ( 1 day 
in the past ) ( Note: previously this would just be a strange double 
value e.g the numeric rep of the date type )

Although I don't really see the point of exponential or division etc. 
operations on dates, keeping the type didn't seem like it would cause 
any problems ( and simplified the code )

However, given previous bad experiences with basic with seemingly minor 
changes in combination with your query I am getting nervous :-/
> i.e. substracting two dates should return a number of days (I don't 
> think adding/multiplying/dividing two dates makes sense, but it should 
> return a number of days as well).
hmm  Date 'operation' Date puts a different spin on things :-/

with the change on master

dim tomorrow as Date
dim yesterday as Date

tomorrow = date() + 1
yesterday = date() - 1
result = tomorrow - yesterday ' previously would have given 2 as a 
result with a type variant/double but now gives a strange date ( result 
of trying to convert 2 into a date )

and of course... that's not good :-(

However I'd still like to see macro code like

    something = date() - 1

return a date just like the addition case

We have a number of choices

a) safest, just restore the old code
b) not so risky ( I think ), and... would change the present behaviour 
in consistent way for treatment of minus operator
-                    if( GetType() == SbxDATE || rOp.GetType() == SbxDATE )
+                    if( ( eOp == SbxPLUS || eOp == SbxMINUS ) && ( ( 
GetType() == SbxDATE || rOp.GetType() == SbxDATE ) && ( GetType() != 
rOp.GetType() ) ) )
c) risker variant of b that allows all operations on a date type to 
retain it's date type

-                    if( GetType() == SbxDATE || rOp.GetType() == SbxDATE )
+                    if( ( GetType() == SbxDATE || rOp.GetType() == 
SbxDATE ) && ( GetType() != rOp.GetType() ) )


Given past history I'd choose b) but I'd like to hear other opinions ( 
also cc'ing Andrew ) and of course be glad of some other eyes for the change

regards,
Noel