[Lazarus] exception handling

[Hans-Peter Diettrich]

Andrea Mauri schrieb:

> The calculations are under try except.

For what reason?

An exception down in some calculation doesn't give you any clue of what 
exactly went wrong, only that *something* went wrong.

> Sometimes happens that the argument (a) of b:= ln(a) is negative.

I'd check this just before the operation, then you won't get an 
exception at all. You can wrap that in a MyLn function, if you need ln() 
more often.

DoDi