EDT:EGL Language Part Types

Please see the parent of this page, EDT:EGL Language.

Part Types (Table 1)

Part Types	Core	JavaScript	Java	Debug
DataItem1	2d	JS: DataItem
Function2, 5	done	JS: Function overloading
Top-level function2, 5	done
Delegate2	done	JS:Delegates
Record	done	JS:Record
Structured Record	done	N/S	N/S	N/S
ExternalType	done	JS:ExternalType
Handler	1d	JS:Handler
Library	done	done
Service	1d
Interface3	done
Enumeration		JS: Enumeration
Program4	done	N/S
Array
Nullability6
DataTable	done	N/S	N/S	N/S
Form	done	N/S	N/S	N/S

Notes on Table 1

1. In RBD a DataItem can only be used for primitive types. In EDT it can be used for any type.
2. See also Table 2: Function Parameters.
3. Interfaces can be implemented by services and handlers (every kind of "logic part" which can be instantiated).
4. There are no called programs in EDT. Use libraries for "local calls" and services for "remote calls".
5. We intend to support function overloading in all implementations, even JavaScript.
6. Nullability means that a variable may really be null. It's not an "I'm null" flag like in RBD. A NullValueException will be thrown if you try to access a field or function of a null variable, even a record. A NullValueException will be thrown if a null variable is an operand to a math operator, an array access, a substring access, a comparison, or a bitwise operator. The string concatenation operators will work the same as in RBD with respect to nulls.  :: treats null as the empty string, and ?: results in null if either operand is null. A question mark won't be allowed on the second operand of the AS and ISA operators (the name of the type).