Pathmaker Reference Manual

Constructs Explained
Macro Language Construct Variables
C–2 067869 Tandem Computers Incorporated
Importance of Context A construct is valid only if an appropriate set of variables has been initialized before
the construct is invoked. This set of variables creates a context for the construct. You
must use ITERATE constructs to initialize the variables that create context for all other
constructs.
If you want to use a construct, check the description that accompanies the construct to
determine the required context. Typically, the context requirement is fulfilled when
you establish one or more current objects using ITERATE constructs. Look for the
phrase, “There must be a current...” to identify an object to be established as a current
object. Then refer to the list of ITERATE constructs to locate the construct or
constructs required to establish that object as the current object.
You will often find that the context you need represents a hierarchy of current objects.
That is, a construct for a file data column requires a current server file; and the
construct for the server file requires a current server. Each required current object is
established by the appropriate ITERATE command. Figure C-1 illustrates the
hierarchical relationship between ITERATE server constructs. Figure C-2 illustrates
the hierarchical relationship between ITERATE requester constructs.
Be sure to execute the necessary ITERATE construct or constructs before executing the
construct you want. An attempt to invoke a construct outside its required context
results in a fatal error at generation time. The system displays the message:
Skel-No context for construct: line number
where line number is the line number on which the invalid construct appeared.