DMN12 — BigDecimal is not the only mapping of number to Java

Clause 10.3.2.9 shows FEEL number values as mapped to XML decimal, integer, and double, but the only mapping to Java is to BigDecimal. The appropriate mapping to Java, like the appropriate mapping to XML, depends on the range and intent of the data element. BigDecimal is rarely used for anything but currency. Java int and double are much more likely to be appropriate for most data items. The mapping of number to Java should be just as flexible as the mapping to XML and PMML.

still no proposals in 4 years, defer.

FEEL chose the simplicity of a single numeric type. Possibly some vendors have extensions, but none has volunteered to make a detailed proposal. There are many numeric builtins and operators; a complete proposal would be somewhat tedious.