Java: use BigInteger and BigDecimal (?) for Integer and Double built-in tokens

[gapag]

BNFC 2.5., with -java option

Consider the following grammar:

Label. Category ::= Integer;

The generated parser accepts the string

1111111111

but fails in

11111111112

Reason: the parser parses the string into an java.lang.Integer object

Workaround: Use tokens, e.g.

token MY_DIGITS digit+;

and process afterwards the string.

Possible solution: Use a java.math.BigInteger field instead of java.lang.Integer, so that the information that the field is numeric (and integer) is preserved without bounds on its precision.

A similar problem arises with the grammar

Label. Category ::= Double;

In that case it is subtler because an overflowing number (wrt the ieee 64 bits double format) is converted into a java.lang.Double to the value Infinity. Therefore the parsing does not fail, but implicitly the semantics of ieee 64 bits floating-point numbers is given to the parsed string.

A solution coherent with the one about integers is to use java.math.BigDecimal instead of java.lang.Double