json_ParseNumber significant digit check possibly too strict

[zgrose]

' Excel only stores 15 significant digits, so any numbers larger than that are truncated
' This can lead to issues when BIGINT's are used (e.g. for Ids or Credit Cards), as they will be invalid above 15 digits
' See: http://support.microsoft.com/kb/269370
'
' Fix: Parse -> String, Convert -> String longer than 15 characters containing only numbers and decimal points -> Number
If Not JsonOptions.UseDoubleForLargeNumbers And Len(json_Value) >= 16 Then

The value 1234567890.12345 has 15 significant digits (and will display in Excel 2016 without truncation) but has length = 16 because the decimal adds to the length without altering the significance. Perhaps test for "." in the json_Value string and allow for 17 characters with a decimal and 16 without?

[timhall]

Thanks @zgrose I think you're right on this, I'll investigate further.