and

Type

operator

Summary

Allows the construction of compound boolean expressions, which evaluate to true if both operands are true, false otherwise.

Syntax

<leftValue> and <rightValue>

Description

Use the and operator to combine two or more logical values into a compound boolean expression.

If leftValue is false or rightValue is false, or if both leftValue and rightValue are false, then the and operation evaluates to false. If leftValue and rightValue are both true, the expression leftValue and rightValue evaluates to true. In an expression with more than two operands, there is an implicit grouping of the first pair, so that the first pair is evaluated first, then subsequent values are evaluated. If any of the operands evaluates to false, the entire expression evaluates to false. You can combine the logical operators and, or, and not in an expression.

note

LiveCode uses what is known as "short-circuit evaluation" for logical operators. This means that leftValue is evaluated first. If leftValue is false, the expression leftValue and rightValue is false regardless of what rightValue is (because the expression evaluates to false unless both the values are true). In this case, LiveCode does not evaluate rightValue, since doing so is not necessary to determine the value of leftValue or rightValue. 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 = 0) and (asin(2) = 1) does not cause an error: since (1 = 0) is always false, the whole statement is always false and LiveCode never tries to evaluate the asin function.

Parameters

Name	Type	Description
leftValue	bool	leftValue is true or false, or an expression that evaluates to true or false.
rightValue	bool	rightValue is true or false, or an expression that evaluates to true or false.

Examples

put (1 > 0) and (1 = 0)
-- evaluates to false

put (1 > 0) and (1 = 1) and (0 = 0)
-- evaluates to true

local myCount
if the shiftKey is down and myCount > 1 then exit mouseUp

Related

operator: bitAnd, not, or

constant: false, true

function: asin, value

glossary: argument, boolean, evaluate, execution error, expression, function, logical, operand, operation, operator, value

Compatibility and Support

Introduced

LiveCode 1.0

OS

mac

windows

linux

ios

android

web

Platforms

desktop

server

mobile