HP TACL User Manual

3 Developing TACL Routines
107365 Tandem Computers Incorporated 3–1
TACL routines provide features that you cannot obtain from any other type of TACL
variable. In a routine, you can:
Use #ARGUMENT to check the syntax and validity of several types of arguments
or to parse data within your program
Use #RESULT to return a specific result (instead of an expansion of text)
Use #ROUTINENAME to obtain the name of the active routine, for issuing
recursive calls
Use #RETURN to exit from any location in the routine
Create an exception handler that processes events or errors
The following subsections describe how to use these features.
Processing Arguments When you invoke a routine, you can include a list of arguments after the routine name.
A routine does not, however, access these arguments in the same manner as macro
arguments (%n%). Instead, in your routine, you specify an #ARGUMENT function
with a list of argument alternatives. The #ARGUMENT function steps through the list
and checks to see if the current argument matches a specified alternative. If the
argument matches, #ARGUMENT returns an index to the alternative and optionally
stores the argument in a variable for use within the routine.
The following statement checks to see if the next argument is a valid subvolume name
(SUBVOL alternative) or system name (SYSTEMNAME alternative):
#SET num [#ARGUMENT /VALUE name/ SUBVOL SYSTEMNAME]
If the argument is a valid subvolume name, #ARGUMENT assigns 1 to num, indicating
that the argument is a subvolume name, and stores the qualified argument in name.
(The VALUE option affects how the #ARGUMENT built-in function stores the
argument. For more information, see the TACL Reference Manual.)
The following examples show differences between argument processing in macros and
routines. The programs support the following syntax:
process_argm file-name
process_argr file-name

HP TACL Specifications

General

Name	HP TACL
Purpose	Task automation, system management, and application control
Category	Software
Platform	HP NonStop
Type	Scripting language
Developer	Hewlett-Packard

Summary

Section 1 An Overview of TACL

Running the Examples in This Manual

Instructions for executing manual examples, including setting required variables.

About This Manual

Section 2 Developing TACL Programs

Processing Character Data

Covers tasks like constructing text strings, analyzing output, and manipulating characters.

Debugging TACL Programs

Introduces the TACL debugger for step-by-step execution and variable examination.

Section 3 Developing TACL Routines

Processing Arguments

Details how routines handle arguments using #ARGUMENT, including options and alternatives.

Writing an Exception Handler

Explains handling events like BREAK keys or TACL errors using exception handlers.

4 Accessing Files

#REQUESTER Operation

Describes the #REQUESTER function for opening files and initiating I/O operations.

Requesting Waited Reads

Explains opening files for waited read operations using #REQUESTER.

5 Initiating and Communicating With Processes

Initiating a Process: RUN and #NEWPROCESS

Covers starting processes using RUN and #NEWPROCESS, including startup options.

Using the INLINE Facility

Using INV and OUTV

Using $RECEIVE

Using #SERVER

6 Running TACL as a Server

Running a TACL Process as a Server

Explains making a TACL process a server by establishing its IN file as $RECEIVE.

Running TACL Code as a Server

Details providing TACL code for a TACL-server process using #INPUTV and #REPLYV.

Using TACL as a Pathway Server

Describes creating a Pathway environment with TCP and TACL servers to process requests.

7 Using Programmatic Interfaces

Overview of SPI and EMS

Using SPI

Using EMS

8 Example of a System Management Program

Monitoring System Operation