Re: [5.3] Converting a floating point number to integer.

[Dirk Laurie <dirk.laurie@...>]

2014-11-16 15:09 GMT+02:00 Liam Devine <liamdevine@oolua.org>:
> I am trying to convert a floating point number to an int and the beta
> release seems to have added some more restrictions on the conversions.

The documentation is unambiguous on this point.

| The conversion from float to integer checks whether the float has an exact
| representation as an integer (that is, the float has an integral
value and it is
| in the range of integer representation). If it does, that
representation is the
| result. Otherwise, the conversion fails.

> What is the current recommended method of converting a float to int?
> Should it be to check if it is greater than zero and floor else use
> ceiling and then finally use one of the above conversion methods?

Converting a float with a non-zero fraction part to an integer
is application-dependent. The user must decide what is correct
for his application: floor, ceil, closest (coded e.g. as floor(x+0.5)),
truncate (as you suggest) or error. The current default of `nil` in
effect opts for error, except that the error is only signalled later.

> If this behaviour is to stay, would it be time to have a cast operator
> int() ?

You mean, Lua should pre-choose among the four options above
and elevate that from plausible to preferred?