Query/View/Transformation Operational Mapping Language - Eclipse Modeling Project: A Domain-Specific Language Toolkit - page 565

var topics : Sequence (Topic) :=
self .elements->select( oclIsTypeOf (Topic)->collect( oclAsType (Topic));
-- using shorthand, the following is equivalent:
var topics : Sequence (Topic) :=
self .elements[ oclIsTypeOf (Topic)]. oclAsType (Topic);
13.5.2 Imperative Operations
QVTO provides a number of imperative operations, including forEach ,
forOne , while , and switch . Additionally, imperative versions of OCL are
available. This section describes each and provides examples of their use.
forEach
The forEach imperative loop expression executes the loop for all the elements
in the collection for which the conditional expression holds. QVTO currently
does not support this expression.
forOne
The forOne imperative loop expression executes the loop for only the first ele-
ment in the collection that satisfies the conditional expression. QVTO currently
does not support this expression.
while
The while control expression iterates on an expression until its condition is
false . You can terminate a while using a break, or you can direct execution to
the beginning of the next iteration at any point using the continue expression.
Following is an example of a while loop used to create a table name from a class
name:
/**
* Replaces camel case with underscore, e.g. firstName -> FIRST_NAME
*/
query String ::toColumnName() : String {
var name : String := '';
var digit : String := '';
var pos : Integer := 1;
while (pos <= self .size()) {
digit := self .substring(pos, pos);
if digit.toLowerCase() <> digit then {