2.4 USE OF A PAR FILE AS A PROC

TCL permits the proc field of a command line to be the file specification of a PAR file. "Executing" a PAR file is like executing a PARMSET PDF: there is nothing to execute, but all of the TAE features (save, restore, tutor, etc.) associated with proc execution are available. This feature exists because:

• there is often no PDF associated with a PAR file, for example, a PAR file constructed from scratch by an application program, and
• reading a PAR file is faster than reading and compiling a source PDF.

Some examples of using a PAR file as a proc follow:

1. The following command line updates a PAR file:

      TAE> mydata.par  |save=mydata.par|  x=4 y=2
   

   This command creates a new version of the mydata PAR file containing new values for the x and y variables. The above command is similar to:

      TAE>  mydata.pdf|restore=mydata.par, +
      TAE>+ save=mydata.par, runtype=norun|  x=4 y=2
   

   (where + is the line continuation character) but executes faster and requires less typing. Note that in the first command, a full hierarchy search is applied to the PAR file proc, whereas the restore in the second command directly references a PAR file in the default directory.

   The "runtype=norun" clause causes just the parameters to be initialized without the process or procedure being executed.

2. The following command line allows you to tutor on a PAR file:

      TAE> tutor mydata.par
   

   This command is equivalent to tutoring on the mydata.pdf and then using the tutor RESTORE command to access the mydata.par file. When you tutor directly on a PAR file (rather than the associated PDF), no help information is available.

3. The following command defines qualifiers for a TCL variable:

      local x quals=mydata.par
   

   This statement is faster than referencing a PDF for qualifiers. In addition, there are cases where no PDF exists for a PAR file; for example, PAR files created by the TAE Plus WorkBench.