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SECTION 2 Expressions

Note: Boolean Expressions execute when the expression is TRUE so it can be said

that every Boolean expression has an inferred "== TRUE". Sometimes

Boolean expressions can be difficult to read e.g. "bMyFlagPoint" or "BitMask &

0x80. It can help maintenance if this "== TRUE" is explicitly specified e.g.

"bMyFlagPoint == TRUE" or "BitMask & 0x80 == TRUE".

Note: When using Boolean operators (e.g. ==, !=, &&, ||, |) never mix tests for

Boolean and non Boolean operands. For example never use "bMyFlagPoint

== 1" or "bMyFlagPoint == 0". Instead always test using the correct Boolean

constant i.e. "TRUE" or "FALSE" for CX-Supervisor scripts, or "True" and

"False" when using VBScript.

Note: On Condition scripts are only executed when the expression is TRUE.

Sometimes this leads to peculiar results, for example using $Second as it will

be executed when $Second changes to 59, and to 1 but not when it changes

to 0. To execute a condition script any time a point changes, force the

expression to always evaluate to TRUE for example "$Second || TRUE". This

works because the $Second forces the expression to be tested when the point

changes, but the || TRUE means the test will return TRUE regardless of the

value of the point.

Note: Use array points in On Condition expressions with caution. The expression

"MyArray[3] == 1" does not mean "execute every time the third element

changes to 1". It means execute when any element of MyArray changes and

the third element happens to be 1

Note: Using an array point without any index is the same as specifying element 0 i.e.

MyArray actually means MyArray[0] == 1

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