Hack - Programming language

Hack is an open source programming language created in 2014 by Julien Verlaguet and Alok Menghrajani and Drew Paroski.

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Hack is a programming language for the HipHop Virtual Machine (HHVM), created by Facebook as a dialect of PHP. The language implementation is open-source, licensed under the BSD License. Hack allows programmers to use both dynamic typing and static typing. Read more on Wikipedia...

Tags: programming language
There are at least 68,473 Hack repos on GitHub
Early development of Hack happened in Facebook
The Google BigQuery Public Dataset GitHub snapshot shows 3k users using Hack in 3k repos on GitHub
Explore Hack snippets on Rosetta Code
Hack ranks #33 in the TIOBE Index
GitHub supports syntax highlighting for Hack
Indeed.com has 19 matches for "hack developer".
hacklang.org was registered in 2013
See also: (9 related languages) PHP, OCaml, Java, C#, Scala, Haskell, ActionScript, HTML, Parrot

Example from Riju:

<<__EntryPoint>>
function main(): void {
  echo "Hello, world!\n";
}

Example from hello-world:

<?hh
echo "Hello World";

Example from the Hello World Collection:

<?hh
// Hello world in Hack
echo 'Hello World';

Example from Linguist:

<?hh // strict
/**
 * Copyright (c) 2014, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 */

function startup(): void {
  setup_errors();
}

Example from Wikipedia:

<?hh
// Hack functions are annotated with types.
function negate(bool $x): bool {
    return !$x;
}

Language features

Feature	Supported	Example	Token
Strings	✓	"Hello world"	"
MultiLine Comments	✓	/* A comment */	/* */
Print() Debugging	✓		echo
Comments	✓	// A comment
Line Comments	✓	// A comment	//
First-Class Functions	✓
Semantic Indentation	X