| boolean | true-false type |
| Syntax | boolean
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| Description | The boolean type is used for values that are either true or false. These true-false values can be combined by various operators such as or and and.
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| Example |
var success : boolean := false
var continuing := true % The type is boolean
…
success := mark >= 60
continuing := success and continuing
if continuing then …
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| Details | This type is named after the British mathematician, George Boole, who formulated laws of logic. The operators for true and false are and, or, xor, =>, and not. For two true/false values A and B, these operators are defined as follows:
The and operator has higher precedence than or, so A or B and C means A or (B and C). The operators or, and and => are short circuit operators. For example, if A is true in A or B, B is not evaluated.
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| Details | The boolean type can be used as an index to an array.
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| Example | Declaration of an array with boolean index.
var a : array boolean of int
a (false) := 10
a (true) := 20
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| Details | The put and get semantics allow put's and get's of boolean values. true values will be output as "true" and false values will be output as "false". The only legal input values are "true" and "false", which are case sensitive.
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| See also | explicitTrueFalseConstant (which discusses the values true and false), precedence and expn (expression).
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