Indirection within Script Commands and Expressions SECTION 4 CX-Supervisor
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Remarks
Typical Examples
REM The following statement adds two numbers
result = 45 + 754
result = 45 + 754 'add two numbers
4-6 Indirection within Script Commands and Expressions
It is possible to use text points directly or indirectly in place of literal string
arguments within scripts and expressions. For instance, each of the following
commands has the same effect:
• Using a string literal;
PlayOLE("ole_1", 0)
• Using a textpoint directly;
textpoint = "ole_1"
PlayOLE(textpoint, 0)
• Using a textpoint indirectly via the '^' notation.
text = "ole_1"
textpoint = "text"
PlayOLE(^textpoint, 0)
It is possible to use text points indirectly in place of point name arguments
within script commands. For instance, each of the following commands has
the same effect:
• Using a point name directly;
verbnumber = 0
PlayOLE("ole_1", verbnumber)
• Using a textpoint indirectly via the '^' notation.
verbnumber = 0
textpoint = "verbnumber"
PlayOLE("ole_1", ^textpoint)
An example using Indirection
The value of point indirection can be seen in a situation where it is necessary
to dynamically change the pointname that an object is linked to. In the
following example a toggle button is configured to control the Boolean state of
one of four points:
• The four Boolean points to be controlled are called 'motor1', 'motor2',
'motor3' and 'motor4'.
• The text point 'textpoint' is used to store the name of the Boolean point to
be controlled.
• The text point 'text' is used to store the string value of the integer point
'index'
• The integer point 'index' (which has a range 1-4) is used to dynamically
change the point being controlled.
• Access to any of the four Boolean points 'motor1', 'motor2', 'motor3',
'motor4' can be achieved by applying indirection to 'textpoint' using the '^'
notation and changing the contents of 'textpoint'.
For instance, in order to dynamically change the Boolean point a toggle button
is linked to follow these steps.
Argument Type Description
Comment - - - Descriptive text.