Tutorial by Examples: st

It is also possible to create nested actors, i.e. grand-children, like this: // here we pass in the ActorRefFactory explicitly as an example val a = actor(system, "fred")(new Act { val b = actor("barney")(new Act { whenStarting { context.parent ! ("hello from &quot...

Last but not least there is a little bit of convenience magic built-in, which detects if the runtime class of the statically given actor subtype extends the RequiresMessageQueue trait via the Stash trait (this is a complicated way of saying that new Act with Stash would not work because its runtime ...

Open Control Panel -> Programs and Features, choose the Visual Studio 2015 item, and then choose the Change button. In the setup wizard for Visual Studio, choose the Modify button. In the list of optional features to install, select the HTML/JavaScript (Apache Cordova) checkbox, c...

In Visual Studio, choose Tools->Extensions and Updates. In the Updates tab of the Extensions and Updates dialog box, choose Product Updates. If an update for Visual Studio Tools for Apache appears, select it, and then choose the Update button.

The goal with using anonymous structs is to decode only the information we care about without littering our app with types that are used only in a single function. jsonBlob := []byte(` { "_total": 1, "_links": { "self": "https://api.twitch.tv/k...

Once Wildfly is installed by unzipping the distribution, it can be started by running the standalone.sh script on the bin directory: $ ./bin/standalone.sh ========================================================================= JBoss Bootstrap Environment JBOSS_HOME: /mnt/storage/tools...

The StringLength attribute specifies the minimum and maximum length of characters that are allowed in a data field. This attribute can be applied on properties, public fields and parameters. The error message must be specified on the ErrorMessage property on the attribute. The properties MinimumLeng...

Hibernate (and embedded H2 DB) <?xml version="1.0" encoding="UTF-8"?> <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/...

Borland started out with a Pascal compiler that they called "Turbo Pascal". This was followed by compilers for other languages: C/C++, Prolog and Fortran. They also produced an assembler called "Turbo Assembler", which, following Microsoft's naming convention, they called "T...

Suppose that you have a pointer to an object of a polymorphic class: Shape *ps; // see example on defining a polymorphic class ps = get_a_new_random_shape(); // if you don't have such a function yet, you // could just write ps = new Square...

Loop control statements are used to change the flow of execution from its normal sequence. When execution leaves a scope, all automatic objects that were created in that scope are destroyed. The break and continue are loop control statements. The break statement terminates a loop without any furthe...

An extensible derived type may be abstract type, abstract :: base_type end type Such a derived type may never be instantiated, such as by type(base_type) t1 allocate(type(base_type) :: t2) but a polymorphic object may have this as its declared type class(base_type), allocatable :: t1 o...

ansible-playbook -i path/to/static-inventory-file -l myhost myplaybook.yml

Python 2.x2.3 x = 'hello world!' vowels = [x for x in 'AEIOU'] print (vowels) # Out: ['A', 'E', 'I', 'O', 'U'] print(x) # Out: 'U' Python 3.x3.0 x = 'hello world!' vowels = [x for x in 'AEIOU'] print (vowels) # Out: ['A', 'E', 'I', 'O', 'U'] print(x) # Out: 'hello world!' ...

By default Laravel project's public folder exposes the content of the app which can be requested from anywhere by anyone, the rest of the app code is invisible or inaccessible to anyone without proper permissions. After developing the application on your development machine, it needs to be pushed t...

Recursion is when a method calls itself. Preferably it will do so until a specific condition is met and then it will exit the method normally, returning to the point from which the method was called. If not, a stack overflow exception might occur due to too many recursive calls. /// <summary>...

;; package.el is available since emacs 24 (require 'package) ;; Add melpa package source when using package list (add-to-list 'package-archives '("melpa" . "http://melpa.org/packages/") t) ;; Load emacs packages and activate them ;; This must come before configurations o...

Lists are a special kind of compound term. Lists are defined inductively: the atom [] is a list, denoting the empty list. if Ls is a list, then the term '.'(L, Ls) is also a list. There is a special syntax for denoting lists conveniently in Prolog: The list '.'(a, '.'(b, '.'(c, []))) can a...

In all serious Prolog systems, association lists are available to allow faster than linear access to a collection of elements. These association lists are typically based on balanced trees like AVL trees. There is a public domain library called library(assoc) that ships with many Prolog systems and ...

maplist/2 and maplist/3 are higher-order predicates, which allow the definition of a predicate to be lifted about a single element to lists of such elements. These predicates can be defined using call/2 and call/3 as building blocks and ship with many Prolog systems. For example: ?- maplist(dif(a)...