Minor Description
The Avro IDL defines floating point literals as follows:
< FLOATING_POINT_LITERAL:
("-")?
( <DECIMAL_FLOATING_POINT_LITERAL> | <HEXADECIMAL_FLOATING_POINT_LITERAL> )
>
< #DECIMAL_FLOATING_POINT_LITERAL:
(["0"-"9"])+ "." (["0"-"9"])* (<DECIMAL_EXPONENT>)? (["f","F","d","D"])?
| "." (["0"-"9"])+ (<DECIMAL_EXPONENT>)? (["f","F","d","D"])? |
| (["0"-"9"])+ <DECIMAL_EXPONENT> (["f","F","d","D"])? |
| (["0"-"9"])+ (<DECIMAL_EXPONENT>)? ["f","F","d","D"] > |
< #DECIMAL_EXPONENT: ["e","E"] (["+","-"])? (["0"-"9"])+ >
< #HEXADECIMAL_FLOATING_POINT_LITERAL:
"0" ["x", "X"] (["0"-"9","a"-"f","A"-"F"])+ (".")? <HEXADECIMAL_EXPONENT> (["f","F","d","D"])?
| "0" ["x", "X"] (["0"-"9","a"-"f","A"-"F"])* "." (["0"-"9","a"-"f","A"-"F"])+ <HEXADECIMAL_EXPONENT> (["f","F","d","D"])? > |
< #HEXADECIMAL_EXPONENT: ["p","P"] (["+","-"])? (["0"-"9"])+ >
Java allows for "NaN", "Infinity", and "-Infinity" when parsing a Double from a String:
http://docs.oracle.com/javase/6/docs/api/java/lang/Double.html#valueOf(java.lang.String)
The IDL compiler should allow the same set of values as Java Double.valueOf. Among other things, this would allow "NaN" to be used as a default value for float fields in Avro records.
