Tutorial by Examples: io

Database configuration of a rails project lies in a file config/database.yml. If you create a project using rails new command and don't specify a database engine to be used then rails uses sqlite as the default database. A typical database.yml file with default configuration will look similar to fol...

Debug.log's second argument is always returned, so you could write code like the following and it would just work: update : Msg -> Model -> (Model, Cmd Msg) update msg model = case Debug.log "The Message" msg of Something -> ... Replacing case msg o...

There are a few libraries for unit testing in Common Lisp FiveAM Prove, with a few unique features like extensive test reporters, colored output, report of test duration and asdf integration. Lisp-Unit2, similar to JUnit Fiasco, focusing on providing a good testing experience from the REPL. Su...

If, instead of always having a content script injected based on the URL, you want to directly control when a content script is injected, you can use Programmatic Injection. Minimal example JavaScript chrome.tabs.executeScript({file: "content.js"}); CSS chrome.tabs.insert...

There are two basic styles of type conversion in Go: // Simple type conversion var x := Foo{} // x is of type Foo var y := (Bar)Foo // y is of type Bar, unless Foo cannot be cast to Bar, then compile-time error occurs. // Extended type conversion var z,ok := x.(Bar) // z is of type Bar, o...

As Go uses implicit interface implementation, you will not get a compile-time error if your struct does not implement an interface you had intended to implement. You can test the implementation explicitly using type casting: type MyInterface interface { Thing() } type MyImplementer struct {} ...

Relationships are relationship between entities that can be one-to-one or one-to-many. Creating a relationship is not needed to use Core Data.

One is able to nest one exception / try catch block inside the other. This way one can manage small blocks of code which are capable of working without disrupting your whole mechanism. try { //some code here try { //some thing which throws an exception. For Eg : divide by 0 ...

Hibernate has some strategies of inheritance. The JOINED inheritance type do a JOIN between the child entity and parent entity. The problem with this approach is that Hibernate always bring the data of all involved tables in the inheritance. Per example, if you have the entities Bicycle and Mounta...

The map operation is a useful tool when working with arrays and vectors, but it can also be used to deal with Option values in a functional way. fn main() { // We start with an Option value (Option<i32> in this case). let some_number = Some(9); // Let's do some consecutive ...

1) Form Request Validation You may create a "form request" which can hold the authorization logic, validation rules, and error messages for a particular request in your application. The make:request Artisan CLI command generates the class and places it in the app/Http/Requests director...

public class MainApplication extends Application { private static Context context; //application context private Handler mainThreadHandler; private Toast toast; public Handler getMainThreadHandler() { if (mainThreadHandler == null) { mainThreadHand...

Content has been moved back to good 'ol Servlets wiki page

Onsen UI is an open-source framework that helps you build hybrid apps with native like performance. It can be used along with several well known JavaScript frameworks such as AngularJS (1 & 2), ReactJS and jQuery. Loading OnsenUI in a project is as easy as writing some standard tags of HTML in ...

;; disable automatic loading of packages after the init file (setq package-enable-at-startup nil) ;; instead load them explicitly (package-initialize) ;; refresh package descriptions (unless package-archive-contents (package-refresh-contents)) ;;; use-package initialization ;;; install ...

To create a list of constants - assign iota value to each element: const ( a = iota // a = 0 b = iota // b = 1 c = iota // c = 2 ) To create a list of constants in a shortened way - assign iota value to the first element: const ( a = iota // a = 0 b // b = 1 c /...

iota can be used in expressions, so it can also be used to assign values other than simple incrementing integers starting from zero. To create constants for SI units, use this example from Effective Go: type ByteSize float64 const ( _ = iota // ignore first value by assigning to b...

Because iota is incremented after each ConstSpec, values within the same expression list will have the same value for iota: const ( bit0, mask0 = 1 << iota, 1<<iota - 1 // bit0 == 1, mask0 == 0 bit1, mask1 // bit1 == 2, mask1 == 1 _, _ ...

Iota can be very useful when creating a bitmask. For instance, to represent the state of a network connection which may be secure, authenticated, and/or ready, we might create a bitmask like the following: const ( Secure = 1 << iota // 0b001 Authn // 0b010 Ready ...

Download the Datastax PHP driver for Apache Cassandra from the Git project site, and follow the installation instructions. We will be using the "users" table from the KillrVideo app and the Datastax PHP driver. Once you have Cassandra up and running, create the following keyspace and tabl...