[Gambas-user] isNull()

[Fabien Bodard]

Le 25 novembre 2010 00:31, Benoît Minisini
<gambas at ...1...> a écrit :
>> I use IsNull extensively, is that going to be removed?
>>
>> richard
>>
>
> No. I use it extensively too.
>
> Here is the result of my thought:
>
> - You can know the datatype of a variant with the TypeOf() function. You don't
> have to use the current IsXXXX() functions.
>
> - But you often need to know if a string can be converted to a number, an
> integer, a float, a date.
>
> - You normally want to know that for localized strings get from the outside
> (i.e. the user). For non-localized strings, they are intern to your program,
> so you should know what you are doing.
>
> So:
>
>        IsNull(x) -> kept its behaviour.
>        IsInteger(x) -> If Val(x) returns an integer
>        IsFloat(x) -> If Val(x) returns a float
>        IsDate(x) -> If Val(x) returns a date

hum ... isBinary ?

but how do you test if it's not ?

i imagine it is taht :

Function isFloat(Value as variant) as Float
dim fValue as Float

fValue = Val(Value)
if not error then return fValue


end


but in the other side i need to test it :/ again

if isFoat(Value) then print isFloat(Value)

in fact there is not fabulous soluce as we need two thing, known if a
convertion is possible with this datatype and then get the value.

the only one soluce i see is the C way... with a byref value

Function isFloat(Value as variant, Byref Ret as Float) as Boolean
dim fValue as Float

fValue = Val(Value)
if not error then
  Ret  = fValue
  Return True
endif

return

end

Dim fRet as Float

If IsFloat(Value, ByRef fRet) then Print fRet


>
> They should be enough. But I could add:
>
>        IsLong(x) -> If Val(x) returns a Long
>        IsSingle(x) -> If Single(x) returns a Single.
>
> Regards,
>
> --
> Benoît Minisini
>
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-- 
Fabien Bodard