An expression is a series of terms that results in a value. There are several types of expressions:

•	A literal expression is a value that is itself.
•	Operations result in a new value using other values. To perform an operation, you use existing values and operators, such as the plus sign (+).
	open folder (3 +2) of startup disk
	The values of an operation can be other expressions or can be represented by a variable.
•	Reference expressions refer to objects, which you can use to represent values.

Using operator constants

An operation uses an operator to derive a value. AppleScript defines many constants that you can use as operators. Following are some of the operators you can use.

Boolean operators:
These operators result in a true or false value.

	Type		Constant
	Binary logical		and or
	Not (unary operator)		not
	Equals		= is equals is equal to
	Not equal		is not is not equal to
	Greater than		> [is] greater than comes after
	Less than		< [is] less than comes before
	Greater than or equal to		>= is greater than or equal to does not come before
	Less than or equal to		<= is less than or equal to does not come after
	Starts with		starts with begins with
	Ends with		ends with
	Contains		contains
	Does not contain		does not contain
	Is contained by		is in is contained by
	Is not contained by		is not in is not contained by

Miscellaneous operators:

	Type		Constant		Description
	Concatenation		&		Joins values. Results in a List, Record, or String.
	Coercion		as		Converts a value to another class.
	A Reference To		a reference to		Assigns a reference to an object as the value of a variable.

Mathematical operators:
Use these operators with integers, real numbers, and dates.

	Type		Constant
	Addition		+
	Subtraction		-
	Division		÷ /
	Integral division		div
	Remainder		mod
	Exponent		^