Tutorial by Examples: f

This is a type system extension that allows types that are existentially quantified, or, in other words, have type variables that only get instantiated at runtime†. A value of existential type is similar to an abstract-base-class reference in OO languages: you don't know the exact type in contains,...

Originally proposed by Vincent Driessen, Gitflow is a development workflow using git and several pre-defined branches. This can seen as a special case of the Feature Branch Workflow. The idea of this one is to have separate branches reserved for specific parts in development: master branch is al...

This type of workflow is fundamentally different than the other ones mentioned on this topic. Instead of having one centralized repo that all developers have access to, each developer has his/her own repo that is forked from the main repo. The advantage of this is that developers can post to their o...

With this fundamental workflow model, a master branch contains all active development. Contributors will need to be especially sure they pull the latest changes before continuing development, for this branch will be changing rapidly. Everyone has access to this repo and can commit changes right to t...

In this example, documentation for the local function baz (defined in foo.m) can be accessed either by the resulting link in help foo, or directly through help foo>baz. function bar = foo %This is documentation for FOO. % See also foo>baz % This wont be printed, because there is a line w...

As seen in "Lambda Functions", functions can take other functions as a parameter. The "function type" which you'll need to declare functions which take other functions is as follows: # Takes no parameters and returns anything () -> Any? # Takes a string and an integer a...

Lambda functions are anonymous functions which are usually created during a function call to act as a function parameter. They are declared by surrounding expressions with {braces} - if arguments are needed, these are put before an arrow ->. { name: String -> "Your name is $name&q...

We can reference a function without actually calling it by prefixing the function's name with ::. This can then be passed to a function which accepts some other function as a parameter. fun addTwo(x: Int) = x + 2 listOf(1, 2, 3, 4).map(::addTwo) # => [3, 4, 5, 6] Functions without a receiv...

Functions are declared using the fun keyword, followed by a function name and any parameters. You can also specify the return type of a function, which defaults to Unit. The body of the function is enclosed in braces {}. If the return type is other than Unit, the body must issue a return statement ...

If a function contains just one expression, we can omit the brace brackets and use an equals instead, like a variable assignment. The result of the expression is returned automatically. fun sayMyName(name: String): String = "Your name is $name"

Functions can be declared inline using the inline prefix, and in this case they act like macros in C - rather than being called, they are replaced by the function's body code at compile time. This can lead to performance benefits in some circumstances, mainly where lambdas are used as function param...

iex(1)> 1 + 1 2 iex(2)> v 2 iex(3)> 1 + v 3 See also: Get the value of a row with `v`

For instance, a computation involving commands to read and write from the prompt: First we describe the "commands" of our computation as a Functor data type {-# LANGUAGE DeriveFunctor #-} data TeletypeF next = PrintLine String next | ReadLine (String -> next) derivin...

Constructor functions are functions designed to construct a new object. Within a constructor function, the keyword this refers to a newly created object which values can be assigned to. Constructor functions "return" this new object automatically. function Cat(name) { this.name = name;...

When implementing more than one interface that have methods of the same name that include default implementations, it is ambiguous to the compiler which implementation should be used. In the case of a conflict, the developer must override the conflicting method and provide a custom implementation. ...

Forms can be defined, in a similar manner to models, by subclassing django.forms.Form. Various field input options are available such as CharField, URLField, IntegerField, etc. Defining a simple contact form can be seen below: from django import forms class ContactForm(forms.Form): contac...

use std::fs::File; use std::io::Read; fn main() { let filename = "src/main.rs"; // Open the file in read-only mode. match File::open(filename) { // The file is open (no error). Ok(mut file) => { let mut content = String::new(); ...

use std::fs::File; use std::io::{BufRead, BufReader}; fn main() { let filename = "src/main.rs"; // Open the file in read-only mode (ignoring errors). let file = File::open(filename).unwrap(); let reader = BufReader::new(file); // Read the file line by line us...

use std::env; use std::fs::File; use std::io::Write; fn main() { // Create a temporary file. let temp_directory = env::temp_dir(); let temp_file = temp_directory.join("file"); // Open a file in write-only (ignoring errors). // This creates the file if it doe...

git pull