Operator ORELSE (Short Circuit Inclusive Disjunction)

Returns the short circuit-or (Inclusive Disjunction) of two numeric values

declare operator OrElse ( byref lhs as T1, byref rhs as T2 ) as Ret

result = lhs OrElse rhs

The left-hand side expression.
Any numeric or boolean type.
The right-hand side expression.
Any numeric or boolean type.
A numeric or boolean type (varies with T1 and T2).

Return Value:
Returns the short circuit-or (inclusive disjunction) of the two operands.

This operator evaluates the left hand side expression. If the result is nonzero, then -1 (true) is immediately returned. If the result is zero then the right hand side is evaluated, and the logical result from that is returned, returning -1 (true) for a nonzero value or 0 (false) for zero.
(for conversion of a boolean to an integer, false or true boolean value becomes 0 or -1 integer value)

The truth table below demonstrates all combinations of a short circuit-or operation, the '-' denotes that the operand is not evaluated.

Lhs Value Rhs Value Result
0 0 0
0 nonzero -1
nonzero - -1

Short-circuiting is performed - only expressions needed to calculate the result are evaluated. The left hand side lhs is evaluated first, and only if it evaluates to zero (false) is the right hand side rhs also evaluated. If the left hand side evaluation lhs returns non-zero (true), it is known that at that point that the overall condition is true, so the right hand side rhs is not evaluated (skipped).

The return type is almost always an Integer, of the value 0 or -1, denoting false and true respectively. Except if the left and right-hand side types are both Boolean, then the return type is also Boolean.

This operator cannot be overloaded for user-defined types.

' Using the ORELSE operator on two numeric values
Dim As Integer numeric_value1, numeric_value2
numeric_value1 = 15
numeric_value2 = 30

'Result = -1
Print numeric_value1 ORELSE numeric_value2

Differences from QB:
See also:
Back to Short Circuit Operators
Back to Operators
Valid XHTML :: Valid CSS: :: Powered by WikkaWiki

sf.net phatcode