Tutorial by Examples: t

The SKI combinator system is sufficient to represent any lambda calculus terms. (In practice, of course, lambda abstractions blow up to exponential size when they are translated into SKI.) Due to the simplicity of the system, implementing the S, K, and I combinators is extraordinarily simple: A Dir...

string is defined as alias string = immutable(char)[];: so need to use dup to make a mutable char array, before it can be reversed: import std.stdio; import std.string; int main() { string x = "Hello world!"; char[] x_rev = x.dup.reverse; writeln(x_rev); // !dlr...

After running your grammar .g4 file with ANTLR.jar you should have a number of files generated such as : 1.yourGrammarNameListener.py 2.yourGrammarNameParser.py 3.yourGrammarName.tokens ... To use these in a python project include the Python runtime in your workspace so any application you ar...

Frequently you may want to filter structures and other complex data types. Searching an array of structs for entries that contain a particular value is a very common task, and easily achieved in Swift using functional programming features. What's more, the code is extremely succinct. struct Painter...

Changing the edit text's appearance when it's selected, pressed and not selected can be customised easily by adding creating a new style for your edit text like so <style name="EditTextTheme" parent="Theme.AppCompat.Light.DarkActionBar"> <item name="colorContr...

The Autobahn package can be used for Python web socket server factories. Python Autobahn package documentation To install, typically one would simply use the terminal command (For Linux): sudo pip install autobahn (For Windows): python -m pip install autobahn Then, a simple echo server ca...

New Pull Request Whenever you want to create a Pull Request (let's say this is either by a recent change. But, you can also do this with an older change too!), you can go ahead and let GitHub do a lot of the heavy lifting for you and hit the green Compare & Pull Request button (NOT TO BE CONFUS...

To easily select a buffer by filename, you can use: :b [part_of_filename]<Tab><Tab><Tab>...<Enter> The first Tab will expand the word to a full filename, and subsequent Tab presses will cycle through the list of possible matches. When multiple matches are available, you ...

<C-^> will switch to and from the previous edited file. On most keyboards <C-^> is CTRL-6. 3<C-^> will switch to buffer number 3. This is very quick, but only if you know the buffer number. You can see the buffer numbers from :ls or from a plugin such as MiniBufExplorer.

THREE.BoxGeometry builds boxes such as cuboids and cubes. Cubes Cubes created using THREE.BoxGeometry would use the same length for all sides. JavaScript //Creates scene and camera var scene = new THREE.Scene(); var camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHe...

THREE.CylinderGeometry build cylinders. Cylinder Continuing from the previous example, the code to create the box could be replaced with the below. //Makes a new cylinder with // - a circle of radius 5 on top (1st parameter) // - a circle of radius 5 on the bottom (2nd parameter) // - a height...

extension String { func matchesPattern(pattern: String) -> Bool { do { let regex = try NSRegularExpression(pattern: pattern, options: NSRegularExpressionOptions(rawValue: 0)) let range: NSRange = NSMakeRange(...

super keyword performs important role in three places Constructor Level Method Level Variable Level Constructor Level super keyword is used to call parent class constructor. This constructor can be default constructor or parameterized constructor. Default constructor : super(); Pa...

public interface ILogger { void Log(string message); } [Export(typeof(ILogger))] [ExportMetadata("Name", "Console")] public class ConsoleLogger:ILogger { public void Log(string message) { Console.WriteLine(message); } } [Export(typeof(IL...

Label Tag Helper can be used to render label for a model property. It replaces method Html.LabelFor in previous versions of MVC. Let's say you have a model: public class FormViewModel { public string Name { get; set; } } In the view you can use label HTML element and asp-for tag helper: ...

You may need to render some content in view, which is specific to some environment only. To achieve this goal you can use Environment tag helper: <environment names="Development"> <h1>This is heading for development environment</h1> </environment> <envi...

Often one want to show the result of a command executed by root to other users. The tee command allows easily to write a file with user perms from a command running as root: su -c ifconfig | tee ~/results-of-ifconfig.txt Only ifconfig runs as root.

For null check in method Object nullableObject = methodReturnObject(); if (Objects.isNull(nullableObject)) { return; } For not null check in method Object nullableObject = methodReturnObject(); if (Objects.nonNull(nullableObject)) { return; }

In the old fashion way for collection null check List<Object> someObjects = methodGetList(); for (Object obj : someObjects) { if (obj == null) { continue; } doSomething(obj); } With the Objects.nonNull method and Java8 Stream API, we can do the above in this way: ...

Marks are like bookmarks; they help you find places you've already been. TLDR Set them in normal mode with m{a-zA-Z}, and jump to them in normal or visual mode with '{a-zA-Z} (single quote) or `{a-zA-Z} (backtick). Lowercase letters are for marks within a buffer, and capital letters and digits are...