Boolean

Boolean operators behave like a function call that accepts two parameters and returns either TRUE or FALSE, except in the case of !, which is a boolean operator that works with only one parameter.

Unlike most modern programming languages with optimizing compilers, the boolean operators in LSL do not short-circuit. In C, for example, when using ||, if the condition on the left turns out to be true, the computer does not even evaluate the condition on the right; there is no need because we can already tell that the || will return TRUE. Similar logic works for &&: if the first condition is false, there is no need to evaluate the other condition because the && must return FALSE. This leads to speedups in complicated conditionals.

LSL doesn't do this, so if you're expecting it, it may make your code less efficient, or worse yet, incorrect if you're expecting a function in the second half of an || or && not to be called.

Boolean Operators

Note: Operators that expect boolean values from integers (TRUE or FALSE) will treat all non-zero values as TRUE.

Operator	Name	Syntax	Description
&&	AND	var1 && var2	Returns TRUE if var1 and var2 are both TRUE, FALSE otherwise. var1 and var2 must both be integers.
||	OR	var1 || var2	Returns TRUE if either var1 or var2 are TRUE, FALSE otherwise. var1 and var2 must both be integers.
!	NOT	!var1	Returns TRUE if var1 is FALSE, or FALSE if var1 is TRUE. var1 must be an integer.
>	Greater then	var1 > var2	Returns TRUE if var1 is greater then var2, FALSE otherwise. var1 and var2 must be either an integer or a float.
<	Less then	var1 < var2	Returns TRUE if var1 is less then var2, FALSE otherwise. var1 and var2 must be either an integer or a float.
>=	Greater then or equal to	var1 >= var2	Returns TRUE if var1 is greater then or equal to var2, FALSE otherwise. var1 and var2 must be an integer or a float.
<=	Less then or equal to	var1 <= var2	Returns TRUE if var1 is less then or equal to var2, FALSE otherwise. var1 and var2 must be an integer or a float.
!=	Not equal to	var1 != var2	Returns TRUE if var1 is not equal to var2, FALSE otherwise. var1 and var2 can be any type.
==	Equal to	var1 == var2	Returns TRUE if var1 is equal to var2, FALSE otherwise. var1 and var2 can be any type.

Note:

• When using == or != on lists, it's important to remember that only the list lengths are compared. So "["a"] == ["b"]" would return TRUE, the same as "llGetListLength(["a"]) == llGetListLength(["b"])".
• Do not confuse the assignment operator "=" with the equality operator "=="! When comparing two values, use "==". When assigning a value, use "=". The compiler will not catch your error, as it's possible to assign values within an IF statement delibeartely. Compiling a script with "=" rather than "==" will probably cause the statement to evaluate to TRUE and the conditional variable to become corrupted.

These operators are often used in conditional statements.

---

Types | Operators