Basic Expressions

The following items can be used in an expression:

• Parameters
  A parameter in an expression is replaced by the value of the parameter.
• Constants
  A constant in an expression is replaced by the value of the constant.
• Variables
  A variable in an expression is replaced by the current value of the variable.
• Strings
  A string is a sequence of characters between double quotes ("). (Use "" to insert a single " in the string.)
• Numbers
  A number can be written in one of the following notations:
  Decimal: as a sequence of digits.
  Hexadecimal: as a sequence of hexadecimal digits (0-9, a-f), prefixed with "0x".
  Example:
  The number 42 is written as 42 in decimal or 0x2a in hexadecimal.
• Booleans
  Boolean values can be used in expressions where a conditional value is expected. The Boolean values are True and False.
• Parentheses
  Any expression can be enclosed in parentheses to affect the order of evaluation.