It’s Delphi, but I’ve not seen practical implementations in C# either.
(the updated version thanks to Anders Melander).
–jeroen
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An elaborate wrapper around the Define column is jedi.inc which is used in many projects (both open source and closed source) to distinguish between various Delphi versions, libraries and platforms at compile time (URL: github.com/project-jedi/jedi/blob/master/jedi.inc)
Empty arrays are not used often as arrays usually are about the presence data, not about the absence.
Here are two ways based on the int data type in C# (the original [WayBack] examples [WayBack] are using string, but since string itself is also a kind of array…):
Specify a size of zero:
int[] a = new int[0];
Specify an empty initialisation:
int[] a = new int[] { };
Though many people think arrays are a thing of the past, I think it is one of the first generic types and have their place. For one, enumerating over arrays using foreach is a lot faster in many environments than enumerating over other data types. Another thing is that the fixed nature of arrays can be very beneficial in setting constraints.
It comes down to these cases for XML elements having maxOccurs="1" (which the default for maxOccurs):
adding nillable="true" will convert from a regular type to a nullable type.
adding minOccurs="0" will add boolean …Specified properties in the generated C# for each element.
you can have both nillable="true" and minOccurs="0" in an element which gets you a nullable type and a …Specified property.
Note I’m not considering fixed or default here, nor attributes (that have use instead of minOccurs/maxOccurs, but do not allow for nillable) nor larger values of maxOccurs (which both xsd.exe and xsd2code regard as unbounded).
From the above, XML has a richer type system than C#, so in XML there are subtle a differences between:
an explicit nil in the XML element
the XML element being absent
the XML element being empty.
Hopefully later more text and examples to show how to actually work with this.
The Wiert Corner - irregular stream of stuff 