or
Type
operator
Summary
Evaluates to true if either operand is true, false if both operands are false.
Syntax
<value1> or <value2>
Description
Use the or operator to combine two or more logical (true or false) values.
If value1 is true or value2 is true, or if both value1 and value2 are true, then the or operation evaluates to true. Only if both value1 and value2 are false does the expression value1 or value2 evaluate to false.
You can combine the logical operators and, or, and not in an expression.
LiveCode uses what is known as "short-circuit evaluation" for logical operators. This means that value1 is evaluated first. If value1 is true, the expression value1 or value2 is true regardless of what value2 is (because the expression evaluates to true as long as at least one of the values is true). In this case, LiveCode does not evaluate value2, since doing so is not necessary to determine the value of value1 or value2. For example, evaluating the expression asin(2) normally causes an execution error (because 2 is not a legal argument for the arc sine function), but evaluating the expression (1 = 1) or (asin(2) = 1) does not cause an error: since (1 = 1) is always true, the whole statement is always true and LiveCode never tries to evaluate the asin function.
Parameters
| Name | Type | Description |
|---|---|---|
value1 | bool | The value1 and value2 are true or false, or expressions that evaluate to true or false. |
value2 |
Examples
("a" > "b") or ("b" > "a") -- evaluates to true
(1 < 0) or (1 = 0) -- evaluates to false
wait until the controlKey is up or the commandKey is up
Related
glossary: LiveCode, operand, value, operation, operator, logical, expression, evaluate, argument
operator: not, and, bitOr, bitXor
control structure: function
function: asin
Compatibility and Support
Introduced
LiveCode 1.0
OS
mac
windows
linux
ios
android
Platforms
desktop
server
mobile