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| + | #REDIRECT [[oaw]] |
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| − | == Overview ==
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| − | (Insert text here)
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| − | == Version 5 ==
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| − | In Version 5 we want to improve some of the Xtend language concepts and features.
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| − | Codename is Xtend++ :
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| − | === Imports ===
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| − | The import mechanism should be overworked, so that every import is explicite.
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| − | We won't need any metamodel configuration in the workflow nor in the editors anymore.
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| − | This will not only make the setup simpler but will also improve the performance.
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| − | The syntax would change to something like the following:
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| − | import org:openarchitectureware:Extension; // native import
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| − | import EMF "my/package/model.ecore"; // non-native import
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| − | import UML "my/test.profile.uml" as profile; // non-native import with name space definition
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| − | ==== Native import ====
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| − | A native import refers to another extension file imports all public members (types, functions, extensions).
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| − | ==== Non-native Import ====
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| − | A non native import starts with an identifier pointing to an installed adapter.
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| − | The adapter is responsible for loading and converting the members from the given string.
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| − | The syntax in the string is defined by the adapter.
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| − | ==== Namespace definition ====
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| − | All members are included without namespace information. If you need a namespace you can explicitely define one per import.
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| − | ==== Reexport ====
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| − | The reexport keyword will be supported.
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| − | === Object construction pattern ===
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| − | We are thinking about a syntax to create model graphs inline.
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| − | We need this not only for model transformations but also for writing model transformation tests.
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| − | Example:
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| − | new Entity as e {
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| − | name := "Person";
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| − | references += new Reference {
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| − | name := "partner"
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| − | type := e
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| − | }
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| − | }
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| − | ==== Assignments ====
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| − | They are just another syntax for invoking a setter resp. adder-operation (which will be removed).
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| − | === Extensions vs. Functions ===
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| − | I (Sven) would like to discuss if it wouldn't be a good idea to explicitely separate between functions and extensions.
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| − | I think the author of an extension can decide how it should be invoked (<pre>my.ext() vs. ext(my)</pre>).
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| − | This would make the syntax more strict, so we can provide better error messages.
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| − | In addition I think it would make extension files more readable.
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| − | The syntax could look like the following:
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| − | myExtension(String stuff) :
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| − | stuff+"-+"stuff;
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| − |
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| − | context Entity {
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| − | javaName() : name.toFirstUpper();
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| − | allAttributes() : ....;
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| − | stuff(String name) : ...;
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| − | }
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| − | That is functions in a ''context [Type] {}''-Block are extension - everything else is a function.
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| − | === Code blocks ===
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| − | I (Sven) would like to discuss a ruby-like code block syntax.
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| − | A code block is similar to a chain expression ( a-> b-> x) with the additional features:
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| − | * provides variable declarations (Expression returning void) and assignments (Expression returning the assigned value)
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| − | * support early exit using the 'return' keyword, which forces outer code blocks to exit themselfes.
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| − | It's something like a pseudo imperative syntax.
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| − | Example:
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| − | myExtension(String stuff) : {
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| − | var x := stuff.length();
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| − | if (x>56)
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| − | return "Foo";
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| − | else {
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| − | return "Bar";
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| − | }
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| − | }
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| − | A code block is itself an expression consisting of a list of expressions.
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| − | It returns the value returned by the first executed "return-expression", or the value of the last expression.
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| − | === if expression ===
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| − | As seen in the previous example, we want an if-expression. using if, else keywords.
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| − | if (predicate) expression (else if (predicate) expression)* (else expression)?
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| − | The else part is optional and will return null if not defined.
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| − | The following expression will return null:
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| − | if (false) "Holla"
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| − | | valign=top |
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| − | {| border=0 cellspacing=3 cellpadding=4
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| − | ! bgcolor="Gainsboro" | OAW Navigation
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| − | |-
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| − | | bgcolor="GhostWhite" | [[OAW| Main Page]]
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| − | |}
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| − | |}
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