Hex integer literals with decimal

[jclark]

At the moment:

• decimal x = 0x1234; is OK, but
• decimal:fromString("0x1234") gives an error

This is inconsistent: they should both be allowed or not allowed.

The spec also says that decimal:fromString("1234") should be an error, but that is clearly wrong (and jBallerina allows it).

[jclark]

Note that decimal x = 0x1234.0; is not currently allowed.

[jclark]

From an implementation perspective, I am not enthusiastic about allowing decimal:fromString("0x1234"). The standard decimal package decNumber doesn't provide support for it. So we would have to implement it manually using multiplications (at least for numbers out of range of int). The main point of decimal is efficient conversions from string.

We definitely don't want to support literals with hexadecimal exponents for decimal, which means we shouldn't support hexadecimal literals with a . for decimal.

[jclark]

It does not seem consistent to me to allow decimal x = 0x1234; but not allow decimal x = 0x1234.0; But it's pointless work to allow the latter (which would also require hex exponents). So I think the right fix is

• to disallow decimal x = 0x1234;
• change spec to make decimal:fromString("1234") not an error i.e. allow DecimalNumber

@hasithaa Do you agree?

[manuranga]

Both int and float has fromHexString, why not for decimal ?

[jclark]

@manuranga Previous comments explain that.