3 edge cases and non-normalized Decimals

[jakub791]

3 edge cases and non-normalized Decimals

[Patashu]

Former I think is worth fixing. When it doesn't introduce huge performance losses, basic stuff should work the way it works in Number.

Latter is working as intended. Only use fc_nn if you know what you're doing or you're willing to accept arbitrary consequences.

[jakub791]

Ok, thanks for answer.
Honestly yeah, about the 2nd one, you should face the consequences of creating arbitary non-normalized Decimals.

[jakub791]

Hmm. Just throught about it now - new Decimal(true) is 0 which is also probably unexpected?

[Patashu]

I have no idea what that should be. Probably undefined behaviour - why would you ever write that on purpose?

[jakub791]

Because Number(true) is 1 shouldn't new Decimal(true) be 1 too?

[Patashu]

I guess! (Does break_infinity also fail this?)

[jakub791]

Uh, I don't know. I can check

[James103]

I just tested in FE000000, which uses break_infinity.min.js and new Decimal(true) throws TypeError: t.indexOf is not a function with stacktrace s.fromString, new s.

Throws exception from here (-1 !== t.indexOf("e")):

        s.prototype.fromString = function(t) {
            if (-1 !== t.indexOf("e")) {
                var n = t.split("e");

[jakub791]

Oh, because it tries to do fromString if input is not undefined, Decimal or number.

[MathCookie17]

First statement evaluates to true now, as 1.4.1 normalizes infinities. However, second statement is still false, as I set negative infinity to be normalized to have layer Infinity rather than negative Infinity. Patashu, can you explain why Decimal.dNegInf has layer -Infinity? Shouldn't it have sign -1, mag Infinity, layer Infinity? I guess I should have tested 1.4.1 a little more - I'll have to make a 1.4.2 fixing this, but first I think we need to decide what negative infinity should be and why.

Fourth and fifth statements are now false, as they should be. Third is still false, but that's actually intended - NaN is not equal to itself, that's a rule of floating point. In fact, Decimal.eq(Decimal.NaN, Decimal.NaN) returns false.

EDIT: Okay, I've submitted a pull request that makes the normalization of infinities have {-1, -Infinity, -Infinity} for negative infinity, and this makes your second statement true. Once that pull request is merged, this issue can be closed.

EDIT 2: This issue is solved - well, unless we care about the Decimal(true) thing.