It seems reasonable to me to have bigint require GMP

Me, too !! But a part of the Math::BigInt charter is that the module should work with *just* perl installed - that no additional C library should be necessary. That immediately counts out GMP.

For that matter, if you want to use GMP, there's no need to invoke bigint at all. You could just use Math::GMP (or, for access to the complete GMP functionality, <plug> Math::GMPf, Math::GMPq and Math::GMPz </plug>).

I wonder if there are cases where you'd really want to do bignum processing in pure Perl

For the occasional bignum operation, "pure perl" is not necssarily a high price to pay - maybe a few milliseconds more than the cost of loading GMP. (And maybe even a few milliseconds *less* ... faik :-)

But, speaking for myself ... you're right ... *I* certainly don't want to do bignum processing in pure perl.

Cheers,
Rob