Yes, JavaScript has “short-circuit” evaluation. if (true == true || foo.foo){ // Passes, no errors because foo isn’t defined. } Live DEMO if (false && foo.foo){ // Passes, no errors because foo isn’t defined. } Live DEMO
All design processes result in compromises between mutually incompatible goals. Unfortunately, the design process for the overloaded && operator in C++ produced a confusing end result: that the very feature you want from && — its short-circuiting behavior — is omitted. The details of how that design process ended up in this unfortunate place, those … Read more
ANSI SQL Draft 2003 5WD-01-Framework-2003-09.pdf 6.3.3.3 Rule evaluation order […] Where the precedence is not determined by the Formats or by parentheses, effective evaluation of expressions is generally performed from left to right. However, it is implementation-dependent whether expressions are actually evaluated left to right, particularly when operands or operators might cause conditions to be … Read more
Yes, short-circuiting and evaluation order are required for operators || and && in both C and C++ standards. C++ standard says (there should be an equivalent clause in the C standard): 1.9.18 In the evaluation of the following expressions a && b a || b a ? b : c a , b using the … Read more
The And operator evaluates both sides, where AndAlso evaluates the right side if and only if the left side is true. An example: If mystring IsNot Nothing And mystring.Contains(“Foo”) Then ‘ bla bla End If The above throws an exception if mystring = Nothing If mystring IsNot Nothing AndAlso mystring.Contains(“Foo”) Then ‘ bla bla End … Read more
Depending on what exactly you need: is null checks whether the value is null: {% if var is null %} {# do something #} {% endif %} is defined checks whether the variable is defined: {% if var is not defined %} {# do something #} {% endif %} Additionally the is sameas test, which … Read more
Yep, both and and or operators short-circuit — see the docs.
Depends upon the version. The If operator in VB.NET 2008 is a ternary operator (as well as a null coalescence operator). This was just introduced, prior to 2008 this was not available. Here’s some more info: Visual Basic If announcement Example: Dim foo as String = If(bar = buz, cat, dog) [EDIT] Prior to 2008 … Read more