On Fri, 12 Aug 2016 10:24:48 -0700, zef...@fysh.org wrote: > > "9.998999999999999e0".EVAL - "9.998999999999999e0".Num > 1.77635683940025e-15 > > Observe that the same string yields different Num values when interpreted > as a Num literal and when coerced. Where the string is meaningful both > ways, this is a bug. Obviously there are some situations where the > syntax of Perl 6 literals doesn't exactly match what one would expect of > a Str.Num conversion, but that's not the case here. Where the syntax > matches, as it does in this case, or more generally where the same > digits are presented with the same weights, one would expect the core > decimal->float conversion to behave the same for both. > > The conversions yielding different values implies that at least one > of them is individually incorrect. In this case, the coercion yields > the correctly-rounded value, and the literal is getting it wrong. > [perl #128912] is concerned with these conversions being incorrect per se, > and my test case there used the conversion for literals. The difference > between the two forms of decimal->float conversion is not merely a matter > of literals getting it wrong and coercion getting it right: there are also > cases where the coercion gets it wrong. In fact, coercion gets it wrong > in the [perl #128912] test case: both literal interpretation and coercion > get "9.999e-5" wrong in the same way. I have not yet encountered a case > where literal interpretation gets it right and coercion gets it wrong, > but nor can I say that there isn't such a case. > > -zefram
Thank you for the report. This is now fixed. Fix: https://github.com/rakudo/rakudo/commit/a760ac3cfc6426d9bd2fb00db https://github.com/MoarVM/MoarVM/commit/b735866ddee9bd719440e5c82 Test: https://github.com/perl6/roast/commit/4da5909f926e7eb42
