Tutorial by Examples: st

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...

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...

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...

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

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...

Suppose you have a long list of elements and you are only interested in every other element of the list. Perhaps you only want to examine the first or last elements, or a specific range of entries in your list. Python has strong indexing built-in capabilities. Here are some examples of how to achie...

A transaction is a sequential group of SQL statements such as select,insert,update or delete, which is performed as one single work unit. In other words, a transaction will never be complete unless each individual operation within the group is successful. If any operation within the transaction fai...

Detailed instructions on getting shopify set up or installed.

import java.awt.EventQueue; import java.awt.GridLayout; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.awt.event.WindowListener; import java.util.ArrayList; import java.util.List; import javax.swing.JFrame; import javax.swing.JTextArea; import javax.sw...

If you want to have a table organized in column-store format instead of row store, add INDEX cci CLUSTERED COLUMNSTORE in definition of table: DROP TABLE IF EXISTS Product GO CREATE TABLE Product ( ProductID int, Name nvarchar(50) NOT NULL, Color nvarchar(15), Size nvarchar(5)...

CREATE CLUSTERED COLUMNSTORE INDEX enables you to organize a table in column format: DROP TABLE IF EXISTS Product GO CREATE TABLE Product ( Name nvarchar(50) NOT NULL, Color nvarchar(15), Size nvarchar(5) NULL, Price money NOT NULL, Quantity int ) GO CREATE CLUSTERED C...

Erlang on OpenBSD is currently broken on alpha, sparc and hppa architectures. Method 1 - Pre-built Binary Package OpenBSD let you choose desired version you want to install on your system: ###################################################################### # free-choice: ####################...

$ sudo apt-get update $ sudo apt-get install -y build-essential git curl wget $ wget https://storage.googleapis.com/golang/go<versions>.gz You can find the version lists here. # To install go1.7 use $ wget https://storage.googleapis.com/golang/go1.7.linux-amd64.tar.gz # Untar the ...

Detailed instructions on getting teradata set up or installed.

You can setup your client browser to listen in incoming server events using the EventSource object. You will need to supply the constructor a string of the path to the server' API enpoint the will subscribe the client to the server events. Example: var eventSource = new EventSource("api/my-ev...

An event stream to the server can be closed using the EventSource.close() method var eventSource = new EventSource("api/my-events"); // do things ... eventSource.close(); // you will not receive anymore events from this object The .close() method does nothing is the stream is already...

In this iText 5 example, we need to switch between different styles in the same document: The best way to do this in iText 5, is to create a convenience method that creates a Chunk in the style that needs to be used frequently; see the createBgChunk() method: public Chunk createBgChunk(String s,...