GCC uses something called a trampoline. Information: http://gcc.gnu.org/onlinedocs/gccint/Trampolines.html A trampoline is a piece of code that GCC creates in the stack to use when you need a pointer to a nested function. In your code, the trampoline is necessary because you pass g as a parameter to a function call. A trampoline initializes some registers … Read more
Unfortunately, only Closures have “Capture List” feature like [weak self]. For nested functions, You have to use normal weak or unowned variables. func myInstanceMethod() { weak var _self = self func nestedFunction(result : Bool) { _self?.anotherInstanceMethod() } functionExpectingClosure(nestedFunction) }
Compare this, without using nonlocal: x = 0 def outer(): x = 1 def inner(): x = 2 print(“inner:”, x) inner() print(“outer:”, x) outer() print(“global:”, x) # inner: 2 # outer: 1 # global: 0 To this, using nonlocal, where inner()‘s x is now also outer()‘s x: x = 0 def outer(): x = 1 … Read more
function initValidation() { // irrelevant code here function validate(_block){ console.log( “test”, _block ); } initValidation.validate = validate; } initValidation(); initValidation.validate( “hello” ); //test hello
Monomorphization costs. write(), like most filesystem functions in Rust, takes AsRef<Path> instead of Path, for convenience (to allow you to pass e.g. a &str). But that also has a cost: it means that the function will be monomorphized and optimized separately for each type, while there is no real need for that. While it is … Read more
You are basically creating a closure. In computer science, a closure is a first-class function with free variables that are bound in the lexical environment. Such a function is said to be “closed over” its free variables. Related reading: Closures: why are they so useful? A closure is simply a more convenient way to give … Read more
enter is avoided in practice as it performs quite poorly – see the answers at “enter” vs “push ebp; mov ebp, esp; sub esp, imm” and “leave” vs “mov esp, ebp; pop ebp”. There are a bunch of x86 instructions that are obsolete but are still supported for backwards compatibility reasons – enter is one … Read more
If you are using PHP 5.3 you can get more JavaScript-like behaviour with an anonymous function: <?php function outer() { $inner=function() { echo “test\n”; }; $inner(); } outer(); outer(); inner(); //PHP Fatal error: Call to undefined function inner() $inner(); //PHP Fatal error: Function name must be a string ?> Output: test test
Normally you do it to make closures: def make_adder(x): def add(y): return x + y return add plus5 = make_adder(5) print(plus5(12)) # prints 17 Inner functions can access variables from the enclosing scope (in this case, the local variable x). If you’re not accessing any variables from the enclosing scope, they’re really just ordinary functions … Read more
The nested function looks up variables from the parent scope when executed, not when defined. The function body is compiled, and the ‘free’ variables (not defined in the function itself by assignment), are verified, then bound as closure cells to the function, with the code using an index to reference each cell. pet_function thus has … Read more