Inline if and sequences

Question

Hi everyone.
I'm having a strange behavior with inline "if"
var d:Number[];
java.lang.System.out.println(if ((sizeof d)==0) null else d );It was supose to print null, but it prints the sequence, if i put
java.lang.System.out.println(if ((sizeof d)==0) null else 10 );It prints null as it was supose to do!!

Answer 1

It looks like this is because of type inferencing.
java.lang.System.out.println(if ((sizeof d)==0) null else d );
Since 'null' does not imply a type, the type of d is used as the return type from the if, ie. sequence.
java.lang.System.out.println(if ((sizeof d)==0) "NULL" else d );
yields
["NULL"], maybe not what you'd expect! This is because the if returns a sequence, and "NULL" is coerced into a sequence with a single element.
From the language reference: "The type of such an ifExpression is the most specific type that has the type of the first expression as a subtype and also has the type of the second expression as a subtype."
The most specific type that has subtypes of null and Number[] is Number[], and you get an empty Number[] in your first example.
The most specific type that has subtypes of String[] and Number[] is Object[], and you get a Object[] with only "NULL" in my example.
Make sense?