Re: ISA number
Peter Scott wrote:
Have often wanted a way to tell whether a scalar was a number
way to get at the SvIOK and SvNOK results would be great.
SvIOK, SvNOK and "is a number" are not the same thing at all.
Often numbers are strings that just look like numbers. Perl doesn't
eagerly convert stuff into numbers -- it waits until it needs to.
For example:
if (/(\d+)/) {
...
}
$1 is not SvIOK, but it is definitely a number. I seriously
doubt if Perl 6 is going to change this behavior (if it ain't
broken don't fix it...)
IMHO, the language shouldn't know about SvIOK etc. Perhaps
ref() can be supplemented with a typeof() function taking one
or two args. typeof($s) would just return the type of $s.
typeof($s, 'integer') could check to see if $s is coercible
to integer.
- Ken
Re: ISA number
Peter Scott wrote: Have often wanted a way to tell whether a scalar was a number, and rolling a regex each time seemed wasteful given that Perl knew what it was anyway. So a user-friendly way to get at the SvIOK and SvNOK results would be great. The pedestrian way would be a builtin: isnum() or similar. But we have enough creativity here I'm sure we can come up with something far more obfusc^Wconcise :-) Agree here. I've seen people resort to DBI.pm's 'looks_like_number' or using tricks like ($a + 0 eq $a), but really this should be easier. Having said that, it doesn't need to live in the core - and even today it should be relatively easy to write an XS module for this. Hildo
Re: ISA number
Peter Scott wrote: Have often wanted a way to tell whether a scalar was a number, ... So a user-friendly way to get at the SvIOK and SvNOK results would be great. This is one of those rare proposals which can safely be assumed to be proposed, discussed, and accepted without dissent -- before the RFC is even issued! -- John Porter
Re: ISA number
At 12:27 PM 8/7/00 -0700, Peter Scott wrote: Have often wanted a way to tell whether a scalar was a number, and rolling a regex each time seemed wasteful given that Perl knew what it was anyway. So a user-friendly way to get at the SvIOK and SvNOK results would be great. The Sv?OK macros will likely go away in the new internals, or at least be different. It'd be better to figure out what you really want to know. Those macros tell you whether a scalar has already been changed to an integer, float, or string, rather than whether it can be an int, float, or string, for example. Dan --"it's like this"--- Dan Sugalski even samurai [EMAIL PROTECTED] have teddy bears and even teddy bears get drunk
