SECTION 2 -- PROC MANAGEMENT CONCEPTS

A "proc" is a function that may be executed under the Terminal Monitor. There are two types of procs:

• A "process" is an executable program written in some language like FORTRAN or C.

• A "procedure" is a program written in the TAE Command Language (TCL).

A proc is made known to TAE through the existence of a Proc Definition File (PDF). The parameters for a process are defined in the PDF; the program itself is contained in a separate, executable disk file. The PDF for a procedure contains the parameter definitions followed by a sequence of TCL commands. For both processes and procedures, a PDF also contains (or references) the help information for the proc.

The steps for implementing an application proc under TAE are as follows:

1. Create a PDF for the process or procedure, structured as described in this section.

2. Create a help file, or append the help information to the end of the PDF. The help file is a text file that provides the information for TUTOR and HELP. Help files are described in Section 2.15.

3. Review the user interface with the proc's anticipated users; TAE commands may be used to display the proc parameters and help information.

4. If the proc is a procedure, add and debug the body of the procedure(that is, the TCL "program"). See Section 3 for a description of the TAE Command Language (TCL).

   If the proc is a process, write and debug the program and create an executable program file using the host software development utilities. The "TAE Command Language (TCL) Runtime Services, Volume 1: C" and the "TAE Command Language (TCL) Runtime Services, Volume 2: FORTRAN" describe TAE subroutines that are used by application programs.

5. If desired, use the MSGBLD utility to create detailed explanations of the proc's error messages. These explanations are accessed by the end-user with the HELP-MESSAGE command.

6. Place the files from steps 1, 2, 4, and 5 in a proc library accessible to the user. Proc libraries are described in Section 2.13.

7. Update the appropriate menus (Section 4) to reference the new proc.

Using the Graphical Capabilities of TAE Plus

TAE Plus is designed to exploit the capabilities of graphics workstations by providing a set of tools and application-callable routines (the Window Programming Tools package) that support the development of graphical, point-and-click type user interfaces. These capabilities are available to applications running or not running under the Terminal Monitor.

Graphical applications may be initiated using the same mechanisms as any TAE applications, and initial parameters may be supplied through standard PDFs. See the"TAE Plus Overview" and the "TAE Plus User Interface Developer's Guide" and "TAE Plus Programmer's Manual" for more information.

2.1 STRUCTURE OF A PDF

A PDF is a text file created using one of the host's text editors. PDFs are required for process definition, for procedure definition, and for the definition of global variables ("global" PDFs).

2.1.1 Processes

• the process parameters
• local variable declarations
• the globals referenced by the process
• the process subcommands
• the location of the proc's executable program
• the location of the proc's help text

The structure of a process PDF is:

PROCESS  EXECUTE=file-spec  HELP=help-location

    variable declarations

END-PROC

help text

A sample process PDF is shown in Figure 2-1.

Sample Process PDF

!****   Note that a line beginning with the exclamation character
!****   is considered entirely commentary.
!
!****   Note this is a VMS example.
!
PROCESS EXECUTE=TESTS: IMGCOPY
PARM FROM TYPE=(STRING,30) QUALS=QFROM
               !proc QFROM contains declaration of qualifiers
PARM TO TYPE=(STRING,30)
PARM WINDOW TYPE=INTEGER COUNT=4 DEFAULT=(0,1023,0,1023)
END-PROC

The sections of a process PDF are:

• The PROCESS command, described in Section 3.4, specifies the name of the file to be executed and the location of the help information.

  The EXECUTE value specifies the name of the executable file. If no name is specified, the executable file with the same name and library as the proc is used. Under VAX/VMS, for example, if the PDF name is MYLIB:TEST.PDF, the default executable is MYLIB:TEST.EXE.

  The HELP value specifies the location of the proc's help text. "HELP=*" means that the help text is located in the PDF, following the END-PROC statement. "HELP=help-location" references a separate help file. If the HELP value is omitted, the file name assumed is the file with the same name as the proc. The default type for help files is "HLP".

• The "variable declarations" use the PARM command to specify the attributes of the process parameters; the "LOCAL" command to declare local variables; and the "REFGBL" command to declare references to global variables. TCL declarations are described below and in Section 3.4.

• The order of PARM commands in a PDF determines the ordering for positional specification of parameter values in proc invocation and for display on a tutor screen. (See the "TAE Command Language (TCL) User's Manual" for a discussion on positional specification of parameter values.)

• Parameter declarations, local variable declarations, and global variable references may appear in any order.

• Parameters, references to globals, and declarations of local variables may be grouped under SUBCMD commands. A SUBCMD command indicates that the following group of parameters--until the next END-SUBCMD command--apply only to the specified subcommand. See "Subcommands," Section 2.7.

• The help text is optional. The format of the help information in the PDF is exactly the same as in a help file; see Section 2.15.

2.1.2 Procedures

A TAE procedure provides the capability to package an often-repeated group of TCL commands and to selectively control the execution of the commands. The PDF for a procedure specifies:

• the procedure parameter declarations

• local variable declarations and global variable references

• the procedure subcommands

• executable commands

• the location of the help information for the procedure

The structure is:

PROCEDURE  HELP=help-location
    variable declarations
BODY
    Procedure body with executable TCL commands.
END-PROC

A sample procedure is shown in Figure 2-2.

Sample Procedure PDF

PROCEDURE			!IMGCOPY driver for standard images
PARM FROM TYPE=(STRING,30)	!Source
PARM TO   TYPE=(STRING,30)      !Destination

LOCAL WINDOW TYPE=INTEGER COUNT=4

BODY

IF (FROM="alaska")
     LET WINDOW=(0,2048,0,2048)
ELSE-IF (FROM="hawaii")
    LET WINDOW=(0,256,0,256)
ELSE
    LET WINDOW=(0,512,0,512)
END-IF
IMGCOPY @FROM @TO @WINDOW
END-PROC

The sections of a procedure PDF are:

• The PROCEDURE command declares the PDF to be a procedure and specifies the location of the help information.

• The declaration sections are identical to the declaration sections of a process PDF. (See Section 2.1.1)

• "BODY" introduces the sequence of executable TCL commands; the body is terminated by the END-PROC command. A body may contain any proc invocation or TCL intrinsic command except for PARM and SUBCMD.

  Note that TCL procedures are interpreted, thus, each command is executed when it is read by TAE. When a proc invocation line is read, the proc is first searched within the procedure for an internal proc and if not found, then the normal hierarchy search is performed. (See Section 2.12.)

  See Section 3.4 for details on TCL commands that are used primarily in procedures; see the "TAE Command Language (TCL) User's Manual" for a description of user-oriented commands and for the TCL rules for proc invocation.

• The END-PROC command may be followed by help text. See Section 2.15.