TACL Programming

Master the art of writing functions in the Tandem Advanced Command Language (TACL) program in this course. Through student projects and hands-on labs, you will gain valuable experience with TACL programming. After completing this course, you will be able to write macros and routines, perform file I/O, use structured data, and write server functions.

 

• System programmers
• System and network managers
• Application designers
• Application programmers
• System analysts
• Data communications programmers and analysts

• Concepts and Facilities course
• Knowledge of at least one other programming language
• At least six months of programming experience

Overview of TACL features 

• Productivity aids provided by TACL: HISTORY, FC, ?, !, help-facility
• Function key, custom prompts, file name templates, and macro files
• TACL features as a programming language 

TACL variables

• Obtaining information about variables using either commands or built-in functions
• Using commands or built-in functions to create, initialize, modify, and eliminate variables
• Concept of a “frame” and how it relates to managing variables
• Variable stacks and their levels: what they are and how to create, reference, and eliminate them
• Syntax rules for writing TACL functions
• Lab Exercise (20 minutes): Learn and understand how to logon and use TACL function keys 

Directories and segments 

• Creating a segment file containing a library function
• Using the existing segment file by attaching it to a directory
• Getting information on the segment file
• Syntax rules for writing TACL functions
• Lab Exercise (30 minutes): Learn to create and use a segment file 

Editing variables

• Performing variable file I/O
• Performing global editing of a variable
• Performing line editing of a variable
• Performing character editing of a variable
• Locating the position of a string in a variable
• Extracting lines and characters from a variable

Writing functions: macros 

• Syntax required to write macro functions
• TACL’s handling of arguments to macro functions
• TACL’s expansion of macro functions
• Writing macro functions 

Writing functions: #IF statements

•  Write functions that use the TACL #IF | THEN | | ELSE | construct
• Lab Exercise (1 hour)
• Describe the syntax required to write functions in general and macro type functions in particular
• Describe the different forms of the “control” built-in #IF and contrast when to use one form or the other (#IF or #IF NOT)
• Write a macro type function that accepts one or more arguments and ensures that the arguments are correct by making use of the “control” built-in #IF 

Writing functions: #LOOP statements 

• Write functions that use the TACL #LOOP | DO | | UNTIL | construct
• Write functions that use the TACL #LOOP | WHILE | | DO | construct
• Lab Exercise (1 hour)
• Describe the syntax required to write general functions, with particular focus on macro type functions 
• Describe the two forms of the “control” built-in #LOOP and determine when to use #LOOP | DO | | UNTIL | or #LOOP | WHILE | | DO |
• Write a macro type function that outputs all of the volume names on the system 

Writing functions: #CASE statements 

• Writing functions that use the TACL #CASE construct 

Writing functions—debugging 

• Using the TACL debugging facility provided by TACL to aid in getting functions to work
• Lab Exercise (2 hours)
• Start and stop the Debugger
• Set and clear breakpoints
• Display and modify the contents of a variable
• Single step through your function and resume execution of your function
• Describe the syntax for #IF, #LOOP, and #CASE constructs
• Write a function that employs the #CASE built-in 

Writing functions—file I/O 

• How TACL is able to do device independent I/O
• Using #REQUESTER and #WAIT to perform either “waited” or “no-waited” I/O to files and devices

Writing functions—routines

• Writing “Routine” type functions and use #ARGUMENT, #MORE, and #REST
• Lab Exercise (3 hours)
• Modify and write routine functions
• Describe the syntax and usage of #ARGUMENT and #MORE
• Describe additional capabilities that routines offer that macros do not
• Describe the use of the built-ins: #MYSYSTEM, #PROCESSORSTATUS, and #PROCESSORTYPE, #LOOP, and #CASE

Using structures 

• Using a STRUCT to access data  

Inline processing 

• Performing process I/O using the INLINE facility
• Controlling the display of the process output
• Logging the process output to a variable debugger
• Lab Exercise (30 minutes)
• Describe the syntax required to write INLINE functions in general
• Use the INLINE facility for interfacing with the PERUSE utility
• Practice coding techniques using the variable editing built-ins and review the usage of #INPUTV, #LOOP, and #IF
• Describe the use of #INLINEPREFIX, INLPREFIX, #INLINETO, and INLTO
• Write a macro-type function that purges jobs from the spooler and prompts the user for permission to purge each job 

Writing functions—server files

• How the server file facility provides for communication between a TACL function and a process it has activated
• Situations in which it is appropriate to use implicit server files
• Writing functions that use implicit server files
• Lab Exercise (45 minutes)
• Describe the syntax and usage of functions that employ implicit servers
• Describe the usage of the RUN-options:
• INV <var> DYNAMIC PROMPT <var>
• OUTV <var>, and STATUS <var>
• Describe the usage of the following built-ins:
• #APPEND, #APPENDV
• #EXTRACT, #EXTRACTV
• #WAIT • #REQUESTER
• Describe the conditions under which to use implicit servers
• Write functions that make use of implicit servers 

Define process

• Define Process facility
• Using the Define Process variables to start, stop, and manage processes
• Specifying where complete information on the Define Process facility can be found 

Writing functions—exception handling

• Three types of exceptions that TACL allows a function to handle in its own way
• Using the built-in functions #ERRORTEXT, #EXCEPTION, #FILTER, #RAISE, #RESET, and #RETURN
• Structure and the organization of a function that contains “exception handling” code
• Writing functions that contain their own “exception handling” code 

Using DEFINEs 

• Four types of DEFINE classes 
• Their usage and comparing them to ASSIGNs
• Using the DEFINE command within TACL to create a DEFINE, delete a DEFINE, and alter a DEFINE