2016-10-31 22:49 GMT+01:00 John Brant <brant@refactoryworkers.com>:

> On Oct 31, 2016, at 3:58 PM, Martin McClure <martin@hand2mouse.com> wrote:
>
> (1.19 roundTo: (1/10))asFloat
>
> I should note that the final example *should* result in a Float without
> having to have #asFloat sent to it. Per ANSI and traditional Smalltalk
> practice, any operation where the receiver *or* the argument is a Float
> produces a Float.

While ANSI says that the numbers should be converted using the default conversion table, all of the Smalltalk��s that I��ve tried don��t follow that. I��ve tried Dolphin, VW, Pharo, & VAST, and all return fractions. I prefer this behavior over the ANSI behavior.

John Brant

Whatever result species, don't trust (aFloat roundTo: aFraction) too much, they have some chances to be inexact, except for trivial powers of two.

Example:

(1.105 roundTo: 1/100) -> (111/100)
1.105 < (1105/1000) -> true

Though the number was smaller than exact tie (in decimal), it was rounded up.

Indeed, the exact computations have a different opinion:

(1.105 asFraction roundTo: 1/100) -> (11/10)

That's why we must implement round: with exact computations...