Tutorial by Examples: d

Display Logic

The Display Logic module allows you to add conditions for displaying or hiding certain form fields based on client-side behavior. This module is incredibly useful to make forms much more professional by showing only the appropriate fields and without adding a lot of custom JavaScript. Example usag...

silverstripe • Add Ons and Modules

Grouped CMS Menu

The Grouped CMS Menu Module allows you to group CMS menu items into nested lists which expand when hovered over. This is useful when there are so many CMS menu items that screen space becomes an issue.

silverstripe • Add Ons and Modules

Dashboard

The Dashboard module provides a splash page for the CMS in SilverStripe 3 with configurable widgets that display relevant information. Panels can be created and extended easily. The goal of the Dashboard module is to provide users with a launchpad for common CMS actions such as creating specific pag...

silverstripe • Add Ons and Modules

Coproduct of types in Hask

Intuition The categorical product of two types A and B should contain the minimal information necessary to contain inside an instance of type A or type B. We can see now that the intuitive coproduct of two types should be Either a b. Other candidates, such as Either a (b,Bool), would contain a part...

Haskell Language • Category Theory

Fields with makeFields

(This example copied from this StackOverflow answer) Let's say you have a number of different data types that all ought to have a lens with the same name, in this case capacity. The makeFields slice will create a class that accomplish this without namespace conflicts. {-# LANGUAGE FunctionalDepen...

Haskell Language • Lens

How to remove the index.php from url's with using wamp and codeigniter

First thing to do is enable the mod rewrite on wamp go to Apache modules and scroll down the list If not showing tick enable it and then restart all servers. Linux users can also use below terminal command to enable rewrite module sudo a2enmod rewrite Then restart apache using: sudo service...

codeigniter • Removing index.php using WAMP and CodeIgniter

Chainable object design and chaining

Chaining and Chainable is a design methodology used to design object behaviors so that calls to object functions return references to self, or another object, providing access to additional function calls allowing the calling statement to chain together many calls without the need to reference the v...

JavaScript • Method Chaining

Steps to use custom fonts in React Native (Android)

Paste your fonts file inside android/app/src/main/assets/fonts/font_name.ttf Recompile the Android app by running react-native run-android Now, You can use fontFamily: 'font_name' in your React Native Styles

react-native • Custom Fonts

Compound assignment operators

SQL Server 2008 R2 Supported compound operators: += Add and assign -= Subtract and assign *= Multiply and assign /= Divide and assign %= Modulo and assign &= Bitwise AND and assign ^= Bitwise XOR and assign |= Bitwise OR and assign Example usage: DECLARE @test INT = 42; SET @test...

Microsoft SQL Server • Variables

Join parent and child JSON entities using CROSS APPLY OPENJSON

Join parent objects with their child entities, for example we want a relational table of each person and their hobbies DECLARE @json nvarchar(1000) = N'[ { "id":1, "user":{"name":"John"}, "hobbies":[ {...

Microsoft SQL Server • JSON in Sql Server

Programmatically adding a metadata endpoint to a service

When you also want to expose metadata without a config file you can build on the example programmatically creating a ServiceHost: public ConsoleHost() { mHost = new ServiceHost(typeof(Example), new Uri("http://localhost:8000/Example"), new Uri("net.tcp://9000/Example")); ...

wcf • Your first service

Place allocation and cleanup code next to each other

Scope guards allow executing statements at certain conditions if the current block is left. import core.stdc.stdlib; void main() { int* p = cast(int*)malloc(int.sizeof); scope(exit) free(p); }

D Language • Scope guards

Multiple, nested scopes

import std.stdio; void main() { writeln("<html>"); scope(exit) writeln("</html>"); { writeln("\t<head>"); scope(exit) writeln("\t</head>"); "\t\t<title>%s</title>".write...

D Language • Scope guards

Unit Testing Promises with Mocha, Sinon, Chai and Proxyquire

Here we have a simple class to be tested that returns a Promise based on the results of an external ResponseProcessor that takes time to execute. For simplicty we'll assume that the processResponse method won't ever fail. import {processResponse} from '../utils/response_processor'; const ping =...

JavaScript • Unit Testing Javascript

Renamed imports

A local name for an import can be given, through which all references to the module's symbols must be qualified with: import io = std.stdio; void main() { io.writeln("Hello world"); std.stdio.writeln("hello!"); // error, std is undefined writeln("hello!&qu...

D Language • Imports and modules

Renamed and selective imports

Selective imports may also be renamed. void main() { import std.stdio : fooln = writeln; fooln("Hello world"); }

D Language • Imports and modules

Module declaration

Modules have a one-to-one correspondence with source files. The module name is, by default, the file name with the path and extension stripped off, and can be set explicitly with the module declaration. The ModuleDeclaration sets the name of the module and what package it belongs to. If absent, the...

D Language • Imports and modules

Re-use a moved object

You can re-use a moved object: void consumingFunction(std::vector<int> vec) { // Some operations } int main() { // initialize vec with 1, 2, 3, 4 std::vector<int> vec{1, 2, 3, 4}; // Send the vector by move consumingFunction(std::move(vec)); // Here...

C++ • Move Semantics

Find all matches

Using using System.Text.RegularExpressions; Code static void Main(string[] args) { string input = "Carrot Banana Apple Cherry Clementine Grape"; // Find words that start with uppercase 'C' string pattern = @"\bC\w*\b"; MatchCollection matches = Regex.M...

.NET Framework • Regular Expressions (System.Text.RegularExpressions)

Grant and Revoke Privileges.

Suppose, that we have three users : The Administrator of the database > admin The application with a full access for her data > read_write The read only access > read_only --ACCESS DB REVOKE CONNECT ON DATABASE nova FROM PUBLIC; GRANT CONNECT ON DATABASE nova TO user; With th...

postgresql • Role Management