Re: Division by Zero

[John M. Dlugosz]

I think you make a good case. As Perl 5 exists now, I can imagine a pragma being used to control this. Perhaps a special value for use warnings: the SV primitive would consult this warning value to decide whether to die, warn and return undef, or return undef silently.

In the future, with typed values and compiled code, it gets messy. SV-based generic code would return undef, integer code would hit a hardware exception unless it took pains to check every single divisor before doing it, which goes against the reason for compiling down to strongly-typed values.

One of the things I saw mentioned for Perl 6 is "Standardise Handling Of Abnormal Numbers Like Infinities And NaNs". See Perl RFC 38.

If division by zero returned not undef but a special known value representing the indeterminte form, it might get swollowed without ever causing a problem if you multipy by zero or something like that; or you get a suitable error later.

—John