You can only invoke methods with arguments in EL if you’re targeting and running at least a Servlet 3.0 compatible container (e.g. Tomcat 7 or newer, WildFly 8 or newer, GlassFish 3 or newer, etc) with a web.xml declared conform at least Servlet 3.0. This servlet version comes along with EL 2.2 which allows invoking … Read more
You cannot pass explicitly by reference in JavaScript; however if b were an object, and in your function you modified b‘s property, the change will be reflected in the calling scope. If you need to do this with primitives you need to return the new value: function increaseB(b) { // Or in one line, return … Read more
Java always passes arguments by value, NOT by reference. In your example, you are still passing obj by its value, not the reference itself. Inside your method changeName, you are assigning another (local) reference, obj, to the same object you passed it as an argument. Once you modify that reference, you are modifying the original … Read more
Good doc from PyCon a couple years back – Default parameter values explained. But basically, since lists are mutable objects, and keyword arguments are evaluated at function definition time, every time you call the function, you get the same default value. The right way to do this would be: def F(a, b=None): if b is … Read more
I found a good explanation at Pass-By-Name Parameter Passing. Essentially, the body of a function is interpreted at call time after textually substituting the actual parameters into the function body. In this sense the evaluation method is similar to that of C preprocessor macros. By substituting the actual parameters into the function body, the function … Read more
if (param instanceof Array) … Edit. As of 2016, there is a ready-built method that catches more corner cases, Array.isArray, used as follows: if (Array.isArray(param)) …
A reference is semantically the following: T& <=> *(T * const) const T& <=> *(T const * const) T&& <=> [no C equivalent] (C++11) As with other answers, the following from the C++ FAQ is the one-line answer: references when possible, pointers when needed. An advantage over pointers is that you need explicit casting in … Read more
myFunction(undefined,”abc”); this way should work, what is the problem? see here Here is undefined documentation from mozilla, supported by all browsers
It looks like you want to adapt what Josh Bloch calls a Typesafe Heterogenous Container pattern: you are passing a type token Class<T>, and you want back a List<T>. Plain old THC can map a Class<T> to a T in a typesafe manner, but since you actually want a List<T> instead, then you want to … Read more