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• The If Instruction evaluates an expression from a predicate and returns a boolean value true or false.
• Therefore Boolean algebra is applied, e.g. to evaluate expressions such as $returnCode.toNumber == 0.
• For details see JS7 - Expressions for Variables

Binary Operations

• The If Instruction knows of two binary operations, which are and (conjunction) and or (disjunction) with the syntax  && and ||.

  • Possible operations correspond to the following matrix:

    x	y	x && y	x || y
    false	false	false	false
    true	false	false	true
    false	true	false	true
    true	true	true	true

  • Round brackets should be used to group multiple expressions and to control the order of evaluation.
  • Conjunction beats disjunction if no grouping is used, i.e.
    •   x && y || z  is the same as (x && y) || z   
    •   x || y && z  is the same as   x || (y && z) 
  • Both operations using the basic elements true, false cover a number of algebraic laws such as associativity, commutativity and distributivity. For more details see Wikipedia.

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