Short-circuit Evaluation

What is Short-circuit Evaluation

• When part of an evaluation is determined, the rest of the statement does not get evaluated.

Grammar

• “The logical AND and logical OR operators use short-circuit evaluation when considering their expressions.”

Usage

Logical Operators

With a logical AND operator, given the first value is false, there is no way for the expression to pass so we do not evaluate the rest of the conditions. This is known as short-circuit evaluation.

let pitchIsPlayable = false
let haveEnoughPlayers = true
let haveReferee = true

if pitchIsPlayable && haveEnoughPlayers && haveReferee { ... }

Optional Binding

Instead of nesting if statements we can move the conditional logic to the same line as where we optionally bind. If the boolean value at the start of the binding line is false, the rest of the line does not get evaluated.

if pitchIsPlayable, let players = wrappedPlayers { ... }

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