Assignments to the FILECARDS task attribute are referred to as file equations. In WFL jobs, FILECARDS can be abbreviated to FILE. Using this task attribute, the job can modify the attributes of the logical files used by the task. The TITLE attribute can be used to cause the task to use a different physical file than it otherwise would.

You can include a construct called a global file assignment in a WFL job to cause an offspring to use a file declared in the WFL job. A global file assignment assigns a particular file declared by the WFL job to a particular internal name used by the offspring. Whenever the offspring attempts to use the file with that internal name, the system causes it to use the global file instead. This mechanism amounts to a hidden call-by-reference parameter because the job and its offspring use the same logical file.

A unique feature of WFL is the ability to include data specifications in the WFL source program. Whenever an offspring attempts to read from a card reader file, it reads instead from a data specification, if one is available. You can also use data specifications to replace other kinds of input files used by an offspring. To do this, you must include a file equation in the statement that initiates the offspring. The file equation must assign the input file a KIND file attribute value of READER. The offspring then reads lines from the data specification as if they were lines of the input file; for this reason, data specifications are also known as pseudo-reader files.