Ada Programming/Keywords/or

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Logical operator edit

Boolean operator edit

X : Boolean := A < 10 or A > 20;

Boolean shortcut operator edit

In the below example the function G is only called when F(X) returns the value False.

if F(X) or else G(Y) then

    Walk_The_Dog;
 
end if;

This shortcut operator is sometimes used to speed up the evaluation of boolean expressions, but the Ada Style Guide recommends to compare the performance of both forms before switching one to the other. In general, it is good idea to use or else in sake of performance only when the second expression involves a function call.

The or else form is also used when the second expression is known to raise an exception unless the first expression is False.

Unlike C/C++, Ada short-cut operators are not the standard way to evaluate boolean expressions. This is because Ada is designed to do by default what is generally safer, but lets the programmer request a different behaviour.

Boolean operator on arrays edit

The or operator is applied to each pair of boolean elements from the left and right arrays. The result has the same bounds as the left operand.

type Day_Of_Month is range 1 .. 31;            
type Month_Array is array (Day_Of_Month) of Boolean;

X : Month_Array := Function_1;
Y : Month_Array := Function_2;
Z : Month_Array := X or Y;

Bitwise operator edit

The operator or could be used with modular types to perform bitwise operations.

Select statement edit

alternative edit

See Ada Programming/Tasking#Selective waiting.

delay edit

See Ada Programming/Tasking#Timeout.

See also edit

Wikibook edit

Ada 95 Reference Manual edit

Ada 2005 Reference Manual edit

Ada Quality and Style Guide edit

3.1.3 Capitalization

Ada Keywords
`abort`	`else`	`new`	`return`
`abs`	`elsif`	`not`	`reverse`
`abstract` (Ada 95)	`end`	`null`
`accept`	`entry`		`select`
`access`	`exception`	`of`	`separate`
`aliased` (Ada 95)	`exit`	`or`	`some` (Ada 2012)
`all`		`others`	`subtype`
`and`	`for`	`out`	`synchronized` (Ada 2005)
`array`	`function`	`overriding` (Ada 2005)
`at`			`tagged` (Ada 95)
	`generic`	`package`	`task`
`begin`	`goto`	`pragma`	`terminate`
`body`		`private`	`then`
	`if`	`procedure`	`type`
`case`	`in`	`protected` (Ada 95)
`constant`	`interface` (Ada 2005)		`until` (Ada 95)
	`is`	`raise`	`use`
`declare`		`range`
`delay`	`limited`	`record`	`when`
`delta`	`loop`	`rem`	`while`
`digits`		`renames`	`with`
`do`	`mod`	`requeue` (Ada 95)	`xor`

Ada Operators

`and`	`and then`	`>`	`+`	`abs`	`&`
`or`	`or else`	`>=`	`-`	`mod`
`xor`	`=`	`<`	`*`	`rem`	`in`
`not`	`/=`	`<=`	`**`	`/`	`not in`