Re: Lua 5.3: wrong coercion?

[Lorenzo Donati <lorenzodonatibz@...>]

On 16/01/2015 20:53, Dirk Laurie wrote:
> 2015-01-16 21:41 GMT+02:00 Lorenzo Donati <lorenzodonatibz@tiscali.it>:
> > Hi all!
> >
> > I just found something that seems odd in Lua 5.3.
> >
> > According to sect 3.4.3 in the refman:
> >
> > "The conversion from strings to numbers goes as follows: First, the string
> > is converted to an integer or a float, following its syntax and the rules of
> > the Lua lexer. (The string may have also leading and trailing spaces and a
> > sign.) Then, the resulting number is converted to the required type (float
> > or integer) according to the previous rules."
> >
> > Thus if I have a string which is "42" it should be coerced to an integer,
> > since 42 is parsed as an integer constant by the lexer, whereas I get:
> >
> > print( 43, "42" + 1 ) --> 43   43.0
> >
> > where it seems that the addition is a float addition, signaling that one of
> > the operands is float. Is this a bug, an error in the refman or maybe
> > something on my side (Windows 7-64, using 32bit executables compiled with
> > TDM-GCC 4.9.2 32 bit)? Am I missing something?
>
> It also happens under Ubuntu 14.04 LTS. But:

Good to know it is repeatable on other platforms. Was it reported before 
on the list? If it was, did Lua team said something about that?

>     print( 43, tonumber"42" + 1 ) --> 43   43
>
> Let's be careful with the word "bug", shall we? Don't want to annoy people.
> But certainly this seems to be a documentation/implementation anomaly.

Well, if it is by design (so it is not a bug, but an implementation 
detail), and it works differently among platforms, the manual 
overspecified the thing.