Xpand Template Language - Eclipse Modeling Project: A Domain-Specific Language Toolkit - page 619

targetDef.proceed() . It's possible to place the proceed() in the beginning,
thereby providing before advice. To execute the template so that the generator
knows about our advices, we can modify our workflow file. Section 14.1.16,
“Aspects,” covers this, so for now we just show the new output.

# Topic Name, Start Date, End Date
A Topic,Tue Nov 20 10:16:00 EST 2007,Fri Nov 23 12:46:20 EST 2007
A Subtopic,Wed Jun 20 00:00:00 EDT 2007,Sat Aug 09 00:00:00 EDT 2008
Another Topic,Sun Sep 09 00:00:00 EDT 2007,Wed Dec 12 00:00:00 EST 2007
Another Subtopic,Sat Dec 01 00:00:00 EST 2007,
Tue Jan 01 00:00:00 EST 2008
A SubSubtopic,Mon Oct 22 00:00:00 EDT 2007,Sat Dec 08 00:00:00 EST 2007

In general, the aspect-oriented capabilities of Xpand (and Xtend and
Workflow) are key to providing flexibility in your MDD artifacts. Knowing these
capabilities when writing templates helps to keep a fine-grained approach to
«DEFINE» blocks and even inserts extensibility points. These are all recom-
mended practices in general and are exemplified by these capabilities.

14.1.13 Type System

Before moving on to the expression language and Xtend language description,
it's important to understand the underlying type system. You've seen the List type
used in the preceding Xpand examples, so let's cover this and the rest in detail.

Type System API Documentation

This section provides basic information on the properties and operations avail-
able for each of the underlying type system elements, as seen in Table 14-1 and
Table 14-2.

Table 14-1 Object Properties

Type Name Description

Type metaType Returns this object's meta type. This can be useful when

dealing with enumeration types, as in this example:

Boolean isEntity(Class c) :
c.metaType == dnc::MomentInterval ||
c.metaType == dnc::MIDetail ||
c.metaType == dnc::Party ||
c.metaType == dnc::Place ||
c.metaType == dnc::Thing ||
c.metaType == dnc::Description

;