Xpand Template Language - Eclipse Modeling Project: A Domain-Specific Language Toolkit - page 632

objects not in the original collection (it is not a subcollection). The collect oper-
ation does this using the same syntax as the select and reject expressions:

collection.collect( v | expression-with-v )

collect() iterates over the target collection and evaluates the given expres-
sion on each element. In contrast to select, the evaluation result is collected in
a list. When the iteration is finished, the list with all results is returned. For exam-
ple, if the name property of the objects in the collection elements is a String, a
list of Strings is returned:

elements.collect(e | e.name) // returns a list of Strings

Navigation through many objects is common, so a shorthand notation for
collect() makes the expressions more readable. This is just as in OCL, so
instead of using:

self.employee.collect(e | e.birthdate)

You can simply write this:

self.employee.birthdate

In general, when a property is applied to a collection of Objects, it automat-
ically is interpreted as a collect() over the members of the collection with the
specified property.

forAll
Often a Boolean expression must be evaluated for all elements in a collection.
The forAll() operation enables you to specify a Boolean expression that must
be true for all objects in a collection for the operation to return true :

collection.forAll( v | boolean-expression-with-v )

The result of forAll() is true if boolean-expression-with-v is true
for all the elements contained in the collection. If boolean-expression-
with-v is false for one or more of the elements in the collection, the expres-
sion evaluates to false .