2.9 INTERNAL PROCS

A TAE internal proc is a process, procedure or parameter set (PARMSET) definition nested within another proc definition. It provides a way for short, related procs, such as ones declaring parameter qualifiers, to be contained within a single PDF.

The rules governing internal procs are the following:

• An internal proc is invoked exactly the same as an external proc is invoked, that is, by specifying the proc on a TCL command line. Note, however, that the TCL command line that invokes the internal proc must be in the body of the procedure that surrounds the internal proc. The body of the following procedure, for example, invokes the internal proc, INTPROC:

  PROCEDURE
      PROCEDURE NAME=INTPROC     !internal proc 
      PARM P1
      BODY
      WRITE &P1
      END-PROC
  BODY
  INTPROC hello                  !invoke INTPROC
  END-PROC

• With regard to the proc hierarchy search, internal procs are searched for after TCL intrinsic commands, and before the user library.

• Internal procs must start with the PROCEDURE, PROCESS, or PARMSET statement, using the NAME parameter for identification. The HELP value for the internal proc, if specified, is ignored.

• An internal proc is defined entirely within the declaration or body section of the outer proc.

• The help information for the parameters should be placed with the main proc's help text.

• An internal proc must be declared before it is invoked or referenced. An internal proc may not be invoked with RUNTYPE=ASYNC, RUNTYPE=ASYNC-PROCESS or RUNTYPE=BATCH.

• A process initiated using an internal proc may not request dynamic parameters.

• An internal proc may access variables declared within itself or in an outer proc. The definition of a variable is first searched for in the internal proc and if not found, the search moves to the outer proc. The search continues on through the layers of outer procs ending with the outermost proc.

• Variables may only be deleted within the internal proc that defines the variable.

• Processes that are declared as internal procs receive all referenced globals, all locals, and parameters that are declared in enclosing procs. The declaration of global references using the REFGBL command is also acceptable in internal procs.

A convenient use of internal procs is to provide qualifiers for a parameter. In the following example, the internal proc QUALSET provides qualifiers to parameter IMAGE:

!  Typical Invocation:
!  ENHANCE image=bigimage |line=200,band=3|
!
PROCESS     !in ENHANCE.PDF
   PARMSET NAME=QUALSET 
   parm line integer valid=1:3000 
   parm band integer valid=1:8
   END-PROC
parm image quals=qualset
END-PROC