auto a = cast(double) BigIntView!size_t.fromHexString("-afbbfae3cd0aff2714a1de7022b0029d"); assert(a == -0xa.fbbfae3cd0bp+124);
auto a = cast(double) BigIntView!size_t.fromHexString!(char, true)("-afbb_fae3_cd0a_ff27_14a1_de70_22b0_029d"); assert(a == -0xa.fbbfae3cd0bp+124);