The expression 5 || 2 && ++x is equivalent to 5 || (2 && ++x) due to operator precedence. The run time evaluates the expression 5 || 2 && ++x from left to right. As we know in OR if first condition is true it will not check the second condition. So here 5 evaluated … Read more
The or and and short circuit, see the Boolean operations documentation: The expression x and y first evaluates x; if x is false, its value is returned; otherwise, y is evaluated and the resulting value is returned. The expression x or y first evaluates x; if x is true, its value is returned; otherwise, y … Read more
What you propose would create two different usage patterns for nullable types. Consider the following code: bool? a = null; // This doesn’t currently compile but would with lifted true/false operators. if (a) { } // Whereas this provides a consistent use of nullable types. if (a ?? false) { } For consistency in the … Read more
Reasons NOT to use short-circuit evaluation: Because it will behave differently and produce different results if your functions, property Gets or operator methods have side-effects. And this may conflict with: A) Language Standards, B) previous versions of your language, or C) the default assumptions of your languages typical users. These are the reasons that VB … Read more
The && and || operators short-circuit. That is: 1) If && evaluates its first operand as false, it does not evaluate its second operand. 2) If || evaluates its first operand as true, it does not evaluate its second operand. This lets you do null check && do something with object, as if it is … Read more
Objective-C does support short-circuit evaluation, just like C. It seems that in your example myString is NSNull and not nil, therefore myString != nil is true. NSNull is a singleton and is used to represent nil where only objects are allowed, for example in an NSArray. Btw, normally, people write if (!myString && myString.length == … Read more
Since your condition is falsy and so doesn’t return the second argument (<GeneralLoader />), it will return profileTypesLoading, which is a number, so react will render it because React skips rendering for anything that is typeof boolean or undefined and will render anything that is typeof string or number: To make it safe, you can … Read more
No, the B==2 part is not evaluated. This is called short-circuit evaluation. Edit: As Robert C. Cartaino rightly points out, if the logical operator is overloaded, short-circuit evaluation does not take place (that having been said, why someone would overload a logical operator is beyond me).
Due to the low precedence of the ‘or’ operator, or3 parses as follows: sub or3 { my ($a,$b) = @_; (return $a) or $b; } The usual advice is to only use the ‘or’ operator for control flow: @info = stat($file) or die; For more discussion, see the perl manual: http://perldoc.perl.org/perlop.html#Logical-or-and-Exclusive-Or
As a more general apprach, I suggest to introduce condition flags and make usage of assigning comparison results to booleans: dim cond1 as boolean dim cond2 as boolean cond1 = false cond2 = false ‘ Step 1 cond1 = MyObj Is Nothing ‘ Step 2: do it only if step 1 was sucessful if cond1 … Read more