Storten Number and Infinity constants

[FarSeeing]

Add unsafe shortcuts for Number constants (idea taken from #262).

Number.POSITIVE_INFINITY and Infinity to 1/0,
Number.NEGATIVE_INFINITY and -Infinity to -1/0,
Number.NaN to NaN

Transformations are only made if the are no Infinity or NaN in scope, but still there is a curios thing:
using them as array index/property name also gets affected. It (possibly) can lead to a problem, but current browsers handle it correctly:

>>> x = {Infinity: 3}
Object { Infinity=3}
>>> x[Infinity]
3
>>> x[1/0]
3

[RGustBardon]

When it comes to evaluating the production MemberExpression : MemberExpression [ Expression ], this is to be expected. Relevant steps are as follows:

1. “Division of a nonzero finite value by a zero results in a signed infinity.” (11.5.2).
2. “Let propertyNameReference be the result of evaluating Expression.” (11.2.1).
3. “Let propertyNameValue be GetValue(propertyNameReference).” (11.2.1).
4. “If Type(V) is not Reference, return V.” (8.7.1)
5. “Let propertyNameString be ToString(propertyNameValue).” (11.2.1).
6. “If m is infinity, return the String "Infinity".” (9.8.1).

Would it not be more consequent to replace Number.NaN with 0/0 instead of NaN?

[FarSeeing]

Thanks for the explanation.

Also, 0/0 for Number.NaN seems good, made it.

[RGustBardon]

Number.NaN to 0/0

[RGustBardon]

As suggested in #262, should this transformation be applied, it could be more useful to transform -Infinity into 1/-0 instead of -1/0 (cf. #411).