Tutorial by Examples: p

UIGraphicsBeginPDFContextToFile(fileName, CGRectZero, nil); UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, 600, 792), nil); UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, 600, 792), nil); UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, 600, 792), nil); ...

Minimal requirements for WCF service is one ServiceContract with one OperationContract. Service contract: [ServiceContract] public interface IDemoService { [OperationContract] CompositeType SampleMethod(); } Service contract implementation: public class DemoService : IDemoService...

By convention, the functor (-)/2 is often used to denote pairs of elements in Prolog. For example, the term -(A, B) denotes the pair of elements A and B. In Prolog, (-)/2 is defined as an infix operator. Therefore, the term can be written equivalently as A-B. Many commonly available predicates also...

Consider the following block of code. try { using (var disposable = new MyDisposable()) { throw new Exception("Couldn't perform operation."); } } catch (Exception ex) { Console.WriteLine(ex.Message); } class MyDisposable : IDisposable { public vo...

6.0 Introduced in C# 6.0, the Null Conditional Operator ?. will immediately return null if the expression on its left-hand side evaluates to null, instead of throwing a NullReferenceException. If its left-hand side evaluates to a non-null value, it is treated just like a normal . operator. Note tha...

The call/N family of predicates can call arbitrary Prolog goals at run time: ?- G=true, call(G). true. ?- G=(true,false), call(G). false.

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)...

In order to record audio from a user's microphone, we must first gain permission from the user to access the device: navigator.mediaDevices.getUserMedia({ audio: true }) .then(successCallback) .catch(failureCallback); On success, our successCallback will be called with a MediaStream ob...

Predicates that impede or prohibit a declarative reading of Prolog programs are extra-logical. Examples of such predicates are: !/0 (->)/2 and if-then-else (\+)/1 These predicates can only be understood procedurally, by taking into account the actual control flow of the interpreter, and a...

The keyword auto provides the auto-deduction of type of a variable. It is especially convenient when dealing with long type names: std::map< std::string, std::shared_ptr< Widget > > table; // C++98 std::map< std::string, std::shared_ptr< Widget > >::iterator i = table.fin...

BEGIN TRANSACTION INSERT INTO DeletedEmployees(EmployeeID, DateDeleted, User) (SELECT 123, GetDate(), CURRENT_USER); DELETE FROM Employees WHERE EmployeeID = 123; COMMIT TRANSACTION

DCGs can be used for parsing. Best of all, the same DCG can often be used to both parse and generate lists that are being described. For example: sentence --> article, subject, verb, object. article --> [the]. subject --> [woman] | [man]. verb --> [likes] | [enjoys]. object ...

The C-API is the most powerful way to access PostgreSQL and it is surprisingly comfortable. Compilation and linking During compilation, you have to add the PostgreSQL include directory, which can be found with pg_config --includedir, to the include path. You must link with the PostgreSQL client s...

When it comes to maps, usually SCSS is the easier syntax. Because Sass is indent-based, your maps have to be saved in one line. // in Sass maps are "unreadable" $white: ( white-50: rgba(255, 255, 255, .1), white-100: rgba(255, 255, 255, .2), white-200: rgba(255, 255, 255, .3), white-30...

CREATE TABLE person ( person_id BIGINT NOT NULL, last_name VARCHAR(255) NOT NULL, first_name VARCHAR(255), address VARCHAR(255), city VARCHAR(255), PRIMARY KEY (person_id) ); Alternatively, you can place the PRIMARY KEY constraint directly in the column definition: ...

OrientDB is available in two editions: Community Edition is released as an open source project under the Apache 2 license. This license allows unrestricted free usage for both open source and commercial projects. Enterprise Edition is commercial software built on top of the Community Edit...

In ASP.NET Web API, a controller is a class that handles HTTP requests. The public methods of the controller are called action methods or simply actions. When the Web API framework receives a request, it routes the request to an action. To determine which action to invoke, the framework uses a rou...

<template name="myTemplate"> {{#each results}} <div><span>{{name}}</span><span>{{age}}</span></div> {{/each}} </template> Template.myTemplate.onCreated(function() { this.results = new ReactiveVar(); Meteor.call('myMethod'...

A template autorun may be used to (re)subscribe to a publication. It establishes a reactive context which is re-executed whenever any reactive data it depends on changes. In addition, an autorun always runs once (the first time it is executed). Template autoruns are normally put in an onCreated met...

Sometimes a term is defined in multiple sections of the manual. By default, man will only display the first page it finds, which can be annoying for programmers because C functions are documented in a later section than commands and system calls. Use the following to display all pages that match a...