Dial-Up Scripting Command Language Essay

This essay has a total of 1971 words and 23 pages.

Dial-Up Scripting Command Language

Table of Contents

1.0 Overview
2.0 Basic Structure of a Script
3.0 Variables
3.1 System Variables
4.0 String Literals
5.0 Expressions
6.0 Comments
7.0 Keywords
8.0 Commands
9.0 Reserved Words




1.0 Overview

Many Internet service providers and online services require you to manually enter
information, such as your user name and password, to establish a connection. With
Scripting support for Dial-Up Networking, you can write a script to automate this process.


A script is a text file that contains a series of commands, parameters, and expressions
required by your Internet service provider or online service to establish the connection
and use the service. You can use any text editor, such as Microsoft Notepad, to create a
script file. Once you've created your script file, you can then assign it to a specific
Dial-Up Networking connection by running the Dial-Up Scripting Tool.



2.0 Basic Structure of a Script

A command is the basic instruction that a script file contains. Some commands require
parameters that further define what the command should do. An expression is a combination
of operators and arguments that create a result. Expressions can be used as values in any
command. Examples of expressions include arithmetic, relational comparisons, and string
concatenations.


The basic form of a script for Dial-Up Networking follows:

;
; A comment begins with a semi-colon and extends to
; the end of the line.
;

proc main
; A script can have any number of variables
; and commands

variable declarations

command block

endproc

A script must have a main procedure, specified by the proc keyword, and a matching endproc
keyword, indicating the end of the procedure.


You must declare variables before you add commands. The first command in the main
procedure is executed, and then any subsequent commands are executed in the order they
appear in the script. The script ends when the end of the main procedure is reached.



3.0 Variables

Scripts may contain variables. Variable names must begin with a letter or an underscore
('_'), and may contain any sequence of upper- or lower-case letters, digits, and
underscores. You cannot use a reserved word as a variable name. For more information, see
the list of reserved words at the end of this document.


You must declare variables before you use them. When you declare a variable, you must also
define its type. A variable of a certain type may only contain values of that same type.
The following three types of variables are supported:


Type Description

integer A negative or positive number, such as 7, -12, or 5698.

string A series of characters enclosed in double-quotes; for example, "Hello world!" or "Enter password:".

boolean A logical boolean value of TRUE or FALSE.

Variables are assigned values using the following assignment statement:

variable = expression

The variable gets the evaluated expression.

Examples:

integer count = 5
integer timeout = (4 * 3)
integer i

boolean bDone = FALSE

string szIP = (getip 2)

set ipaddr szIP


3.1 System Variables

System variables are set by scripting commands or are determined by the information your
enter when you set up a Dial-Up Networking connection. System variables are read-only,
which means they cannot be changed within the script. The system variables are:


Name Type Description

$USERID String The user identification for the current connection. This variable is
the value of the user name specified in the Dial-Up Networking
Connect To dialog box.

$PASSWORD String The password for the current connection. This variable is the
value of the user name specified in the Dial-Up Networking
Connect To dialog box.

$SUCCESS Boolean This variable is set by certain commands to indicate
whether or not the command succeeded. A script can make

decisions based upon the value of this variable.

$FAILURE Boolean This variable is set by certain commands to indicate
whether or not the command failed. A script can make decisions
based upon the value of this variable.


These variables may be used wherever an expression of a similar type is used. For example,

transmit $USERID

is a valid command because $USERID is a variable of type string.


4.0 String Literals

Scripting for Dial-Up Networking supports escape sequences and caret translations, as described below.

String Literal Description

^char Caret translation

If char is a value between '@' and '_', the character sequence is translated into a
single-byte value between 0 and 31. For example, ^M is converted to a carriage return.


If char is a value between a and z, the character sequence is translated into a single-byte value between 1 and 26.

If char is any other value, the character sequence is not specially treated.

Carriage return
Linefeed
" Double-quote
^ Single caret
" until 10
if !$SUCCESS then
goto BailOut ; jumps to BailOut and executes commands
; following it
endif

transmit "bbs^M"
goto End

BailOut:
transmit "^M"


halt

Stops the script. This command does not remove the terminal dialog window. You must click
Continue to establish the connection. You cannot restart the script.



if condition then
commands
endif

Executes the series of commands if condition is TRUE.

Example:

if $USERID == "John" then
transmit "Johnny^M"
endif


label :

Specifies the place in the script to jump to. A label must be a unique name and follow the
naming conventions of variables.



set port databits 5 | 6 | 7 | 8

Changes the number of bits in the bytes that are transmitted and received during the
session. The number of bits can be between 5 and 8. If you do not include this command,
Dial-Up Networking will use the properties settings specified for the connection.


Example:

set port databits 7


set port parity none | odd | even | mark | space

Changes the parity scheme for the port during the session. If you do not include this
command, Dial-Up Networking will use the properties settings specified for the connection.


Example:

set port parity even


set port stopbits 1 | 2

Changes the number of stop bits for the port during the session. This number can be either
1 or 2. If you do not include this command, Dial-Up Networking uses the properties
settings specified for the connection.


Example:

set port stopbits 2


set screen keyboard on | off

Enables or disables keyboard input in the scripting terminal window.

Example:
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