Expressions are the basic building blocks for statements and actions. A simple definition of an expression is a combination of operators and functions which yield a single result. Expressions may be used wherever a value is required. This is a very important feature since it allows functions and operations to be nested.
The two most fundamental components of expressions are variables and constants. To use a variable in an expression all that is required is to enter the name of the variable. Like all text in VTS, it is irrelevant whether the letters of the variable names are upper or lower case. Anywhere the name of a variable appears in an expression, the value held by that variable will be used in its place:
X + 1
If X has a value of 4, this expression will have a value of 5.