Xpand Template Language - Eclipse Modeling Project: A Domain-Specific Language Toolkit - page 613

« FOREACH expression AS varName [ ITERATOR iterName]
[ SEPARATOR expression]»
. . .
« ENDFOREACH »
The expression can be any collection element within the current context
or a statement that results in a collection. Within the block, each element in the
collection is accessed using the varName you provide. The body of the FOREACH
block can contain other Xpand statements, including nested FOREACH elements.
A special Xpand-provided iterator is accessible by name within the block if the
ITERATOR is specified. A common use for the ITERATOR is to access its counter
for outputting a numerical sequence within the body of the statement. As you
saw earlier, you can declare a SEPARATOR and insert it between elements in the
collection. Section 14.1.13, “Type System,” covers the full list of features that an
iterator offers.
To illustrate the use of an ITERATOR , consider this «DEFINE» block:
« DEFINE NumberedCsvFile FOR Map»
« FILE "numbered-" + title + "-topics.csv"-»
« FOREACH elements.typeSelect(Topic) AS topic ITERATOR i-»
«i.counter0»,«topic.name»,«topic.start»,«topic.end»
« ENDFOREACH »
« ENDFILE »
« ENDDEFINE »
In this case, we're prefixing each line in our output CSV file with an
index obtained by our iterator's counter0 property. The output looks like the
following.
0,A Topic,Tue Nov 20 10:16:00 EST 2007,Fri Nov 23 12:46:20 EST 2007
1,A Subtopic,Wed Jun 20 00:00:00 EDT 2007,Sat Aug 09 00:00:00 EDT 2008
2,Another Topic,Sun Sep 09 00:00:00 EDT 2007,
Wed Dec 12 00:00:00 EST 2007
3,Another Subtopic,Sat Dec 01 00:00:00 EST 2007,
Tue Jan 01 00:00:00 EST 2008
4,A SubSubtopic,Mon Oct 22 00:00:00 EDT 2007,
Sat Dec 08 00:00:00 EST 2007
14.1.6 EXTENSION
Xpand supports the extension of the underlying metamodel through the
«EXTENSION» statement. Declaring an «EXTENSION» import in a template