SIMSCRIPT II.5 Programming Language

SIMSCRIPT II.5 Programming Language
6.9 Deletion of Set Routines
Certain routines are automatically generated for each defined set during the processing of a program
preamble. Sets declared as FIFO (explicitly or implicitly), LIFO, or ranked require different routines
to perform their filing and removing operations. Each generated routine is tailored to individual
program specifications reflecting such operations as set attribute deletions and cascaded set
rankings.
The most generally defined set, an unranked one declared as either FIFO or LIFO, has seven routines
generated for it. Four are for filing and three for removing. The routines are named and their
functions stated in table 6-4.
Table 6-4. Set Manipulation Routines
Routine
Generated
Name
Function
File first T.set Files an entity first or ranked
File last U.set Files an entity last
File before V.set Files an entity before a specified entity
File after W.set Files an entity after a specified entity
Remove first X.set Removes the first entity
Remove last Y.set Removes the last entity
Remove specific Z.set Removes a specified entity
A set declared by the statement:
define QUEUE as a FIFO set
thus has seven routines, T.QUEUE, U.QUEUE, ..., Z.QUEUE generated for it.
Ranked sets, by their definition, do not permit filing first, last, or before or after a specific entity
without attention to the specified set ranking. Hence, ranked sets generate four routines, there being
only one file routine.
In addition, certain set operations are impossible if specific set attributes are not present. For instance,
"filing before" is impossible in a LIFO set if the predecessor attribute has been deleted.
Table 6-5 shows the set attributes that must be present for the indicated set operations to be performed.
Because all set attributes are not required for all set operations, table 6-5 can be used to
determine which attributes to delete in order to save memory space. For example, if a program only
files and removes first, the set attributes L and P can be deleted without penalty. If they are not deleted,
the generated programs keep track of and update them anyway.
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