I’ll explain the main use cases of implicits below, but for more detail see the relevant chapter of Programming in Scala. Implicit parameters The final parameter list on a method can be marked implicit, which means the values will be taken from the context in which they are called. If there is no implicit value … Read more
Method 1 (using new) Allocates memory for the object on the free store (This is frequently the same thing as the heap) Requires you to explicitly delete your object later. (If you don’t delete it, you could create a memory leak) Memory stays allocated until you delete it. (i.e. you could return an object that … Read more
There is a post on dart’s website and it explains it pretty well. Final: “final” means single-assignment: a final variable or field must have an initializer. Once assigned a value, a final variable’s value cannot be changed. final modifies variables. Const: “const” has a meaning that’s a bit more complex and subtle in Dart. const … Read more
It’s for declaring class member variables in PHP4, and is no longer needed. It will work in PHP5, but will raise an E_STRICT warning in PHP from version 5.0.0 up to version 5.1.2, as of when it was deprecated. Since PHP 5.3, var has been un-deprecated and is a synonym for ‘public’. Example usage: class … Read more
Figured it out for myself in the end. It is simple, I was just missing the ** operator to unpack the dictionary So my example becomes: d = dict(p1=1, p2=2) def f2(p1,p2): print p1, p2 f2(**d)
Minimal runnable example Main.java public class Main { public native int square(int i); public static void main(String[] args) { System.loadLibrary(“Main”); System.out.println(new Main().square(2)); } } Main.c #include <jni.h> #include “Main.h” JNIEXPORT jint JNICALL Java_Main_square( JNIEnv *env, jobject obj, jint i) { return i * i; } Compile and run: sudo apt-get install build-essential openjdk-7-jdk export JAVA_HOME=’/usr/lib/jvm/java-7-openjdk-amd64′ … Read more
It allows the differentiation of bitwise const and logical const. Logical const is when an object doesn’t change in a way that is visible through the public interface, like your locking example. Another example would be a class that computes a value the first time it is requested, and caches the result. Since c++11 mutable … Read more
typename and class are interchangeable in the basic case of specifying a template: template<class T> class Foo { }; and template<typename T> class Foo { }; are equivalent. Having said that, there are specific cases where there is a difference between typename and class. The first one is in the case of dependent types. typename … Read more
Yes, it’s called next. for i in 0..5 if i < 2 next end puts “Value of local variable is #{i}” end This outputs the following: Value of local variable is 2 Value of local variable is 3 Value of local variable is 4 Value of local variable is 5 => 0..5
volatile has semantics for memory visibility. Basically, the value of a volatile field becomes visible to all readers (other threads in particular) after a write operation completes on it. Without volatile, readers could see some non-updated value. To answer your question: Yes, I use a volatile variable to control whether some code continues a loop. … Read more