Supporting On Demand Business Applications with the IBM Problem Determination Tools (APA, DT, DT with Advanced Facilities, FA, File Export, FM, WS)

1110 Supporting On Demand Business Applications with the IBM Problem Determination Tools

32.3 Coding STL programs

STL is a high-level structured programming language that can be used to create message

generation decks and define terminals and devices to be simulated by WSim. STL utilizes

constants, variables, expressions, and structured control statements.

An STL program is usually divided into one or more procedures. The STL Translator

translates STL programs into message generation decks, each message generation deck

corresponding to one STL procedure. Network definitions can be included into STL programs.

NTWRKLOG MSGDISK, RATE, UTBL, SIDEINFO,

RN, UDIST, INCLUDE, IF, PATH

Optional

MSGDISK RATE, UTBL, SIDEINFO, RN, UDIST,

INCLUDE, IF, PATH

Optional

RATE RATE, UTBL, SIDEINFO, RN, UDIST,

INCLUDE, IF, PATH

Required if using rate table delays

UTBL UTBL, SIDEINFO, RN, UDIST,

INCLUDE, IF, PATH

Optional

SIDEINFO SIDEENT Optional

SIDEENT SIDEENT, SIDEEND At least one is required after SIDEINFO

SIDEEND RN, UDIST, INCLUDE, IF, PATH Required after the last SIDEENT

RN RN, UDIST, INCLUDE, IF, PATH Optional

UDIST UDIST, INCLUDE, IF, PATH Optional

INCLUDE INCLUDE, IF, PATH Optional, mostly used to define required

but not referenced message generation

decks

IF INCLUDE, IF, PATH Optional

PATH PATH, DIST, UTI, FILE, APPCLU,

VTAMAPPL, TCPIP

At least one is required

DIST DIST, UTI, FILE, APPCLU, VTAMAPPL,

TCPIP

Optional

UTI UTI, FILE, APPCLU, VTAMAPPL,

TCPIP

Optional

FILE FILE, APPCLU, VTAMAPPL, TCPIP Optional

APPCLU TP Optional

TP TP, APPCLU, VTAMAPPL, TCPIP, FE At least one is required after APPCLU

VTAMAPPL LU Optional

LU LU, VTAMAPPL, TCPIP, FE At least one is required after VTAMAPPL

TCPIP DEV Optional

DEV DEV, TCPIP, FE At least one is required after TCPIP

FE FE Optional

Statement Can be followed by Comments

Chapter 32. Basics of scripting for Workload Simulator 1111

The STL Translator invokes the preprocessor to validate and store the network definition

statements.

STL is similar but not equivalent to REXX. STL uses many of the same commands and

functions as REXX. However, STL is not the run-time scripting language; therefore, WSim

must process or translate STL into MSGTXT format prior to test execution.

Variables and constants

In STL, you can use variables and constants as data items in your programs. A variable

contains data that is used by a program in a certain way, but whose value can vary. In a

program, each variable has a unique symbolic name.

Constants are values that do not change in the course of program execution. Constants can

be used to initialize variables, to test the contents of variables, and to generate messages.

They can also make up part of STL expressions. Names can be assigned to most constants.

STL substitutes the actual constant value for the constant name.

Variables are classified as one of three data types:

򐂰 Integer

򐂰 String

򐂰 Bit

Integer variables can take any positive integer value from 0 to 2147483647. When a network

is first initialized, the value of an integer variable is 0. Integer variables translate into counters

in the scripting language. An integer variable's value will wrap if incremented beyond

2147483647 or decreased below 0. That is, if a variable has a value of 2147483647 and 1 is

added to it, the result is 0. If a variable has a value of 2 and 3 is subtracted from it, the result

is 2147483647.

String variables can contain only characters. They must be from 0 to 32767 characters long.

A character can be any 1-byte value, from '00'X to 'FF'x. When a network is first initialized, the

value of a string variable is '' (the null string, which is represented by a pair of single or double

quotation marks). String variables translate into save areas in the scripting language.

Bit variables represent binary data items. STL bit variables can have the value of ON or OFF.

When a network is initialized, all bit variables have a value of OFF. Bit variables translate into

switches in the scripting language.

Special variables are available to be used by your STL program:

BUFFER or SCREEN For nondisplay terminals, the device buffer; for display terminals,

the screen image. Use the SUBSTR and ROWCOL functions to

query a screen area, for example, x =

substr(screen,rowcol(10,20),6).

DATA or TH Incoming or outgoing data, including SNA headers if present.

RH The SNA request/response header (RH) portion of incoming or

outgoing data plus the SNA request/response unit (RU).

RU The SNA Request/response unit (RU) portion of incoming or

outgoing data.

Constants are classified as:

򐂰 Integer

򐂰 String

򐂰 Hexadecimal string

򐂰 Bit data