Re: [bug-gawk] Overflow to Infinity

[Andrew J. Schorr]

Hi,

On Tue, Jun 19, 2018 at 04:03:06PM -0700, Daniel Pettet wrote:
> Gawk is already supporting the '+inf' form within strings in awk source
> code.
> 
> print  +"+inf"           # inf
> print  +"+inf" + 5     # inf
> print  +"-inf"            # -inf
> print  +"-inf" + 7      # -inf
> 
> These illustrate my point and this could be supported when in user input
> data.

Actually, gawk does support +inf and -inf in user input. The only version it
does NOT support is plain old inf (or infinity). But it does work when --posix
is used.  Using the gawk master branch:

bash-4.2$ (echo +inf; echo -inf; echo inf; echo +infinity; echo -infinity; echo 
infinity) | ./gawk '{print $1+0}'
inf
-inf
0
inf
-inf
0
bash-4.2$ (echo +inf; echo -inf; echo inf; echo +infinity; echo -infinity; echo 
infinity) | ./gawk --posix '{print $1+0}'
inf
-inf
inf
inf
-inf
inf

I believe this could be fixed by patching the 
is_ieee_magic_val/get_ieee_magic_val
logic in node.c.

As before, I pass no judgement on whether it would be a good idea to make this
change. I do not pretend to be a language lawyer. :-)

Regards,
Andy