Red (Programming Language)

Red

Paradigm	imperative, functional, symbolic
Designed by	Nenad Rakočević[1]
Developer	Nenad Rakočević
First appeared	2011
Stable release	0.6.4[2] (Alpha) / December 7, 2018
OS	Linux, Windows, OS X, Syllable
License	modified BSD and Boost
Filename extensions	.red, .reds
Website	{{{1}}}
Influenced by
Rebol, Scala, Lua

Red is a programming language designed to overcome the limitations of the programming language Rebol.^[3] Red was introduced in 2011 by Nenad Rakočević,^[4] and is both an imperative and functional programming language. Its syntax and general usage overlaps that of the interpreted Rebol language.^[5]

The implementation choices of Red intend to create a full stack programming language:^[4][6] Red can be used for extremely high-level programming (DSLs and GUIs) as well as low-level programming (operating systems and device drivers). Key to the approach is that the language has two parts: Red/System and Red.^[7]

• Red/System is similar to C, but packaged into a Rebol lexical structure – for example, one would write Template:Smalltalk instead of

  if (x > y) {printf("Hello\n");}

  .
• Red is a homoiconic language^[3] capable of meta-programming, with Rebol-like semantics. Red's runtime library is written in Red/System, and uses a hybrid approach: it compiles what it can deduce statically and uses an embedded interpreter otherwise. The project roadmap includes a just-in-time compiler for cases in between, but this has not yet been implemented.

Red seeks to remain independent of any other toolchain; it does its own code generation.^[3] It is therefore possible to cross-compile^[6] Red programs from any platform it supports to any other, via a command-line switch. Both Red and Red/System are distributed as open-source software under the modified BSD license. The runtime library is distributed under the more permissive Boost Software License.

As of version 0.6.4 Red includes a garbage collector "the Simple GC".^[2]

Red Language architecture schema

Introduction

Red was introduced in the Netherlands in February 2011 at the Rebol & Boron conference^[8] by its author Nenad Rakočević. In September 2011, the Red programming language was presented to a larger audience during the Software Freedom Day 2011.^[9][10] Rakočević is a long-time Rebol developer known as the creator of the Cheyenne HTTP server.^[11]

Features

Red's syntax and semantics are very close to those of Rebol.^[4][12] Like Rebol, it strongly supports metaprogramming and domain-specific languages (DSLs) and is therefore a highly efficient tool for dialecting (creating embedded DSLs). Red includes a dialect called Red/System, a C-level language which provides system programming facilities.^[7] Red is easy to integrate with other tools and languages as a DLL (libRed) and very lightweight (around 1 MB). It is also able to cross-compile to various platforms (see Cross Compilation section below) and create packages for platforms that require them (e.g., .APK on Android).^[7] Red also includes a fully reactive cross-platform GUI system based on an underlying reactive dataflow engine, a 2D drawing dialect comparable to SVG, compile-time and runtime macro support, and more than 40 standard datatypes.

Goals

The following is the list of Red's Goals as presented on the Software Freedom Day 2011:^[9][10]

• Simplicity ("An IDE should not be necessary to write code.")
• Compactness ("Being highly expressive maximizes productivity.")
• Speed ("If too slow, it cannot be general-purpose enough.")
• Be "Green", Have a Small Footprint ("Because resources are not limitless.")
• Ubiquity ("Spread everywhere.")
• Portability, Write once run everywhere ("That's the least expected from a programming language.")
• Flexibility ("Not best but good fit for any task!")

Development

Red's development is planned to be done in two phases:

1. Initial phase: Red and Red/System compilers written in Rebol 2
2. Bootstrap phase: Red and Red/System compilers complemented by a Red JIT-compiler, all written in Red

Cross compilation

Red currently supports the following cross-compilation targets:

• MS-DOS: Windows, x86, console (and GUI) applications
• Windows: Windows, x86, GUI applications
• Linux: Linux, x86
• Linux-ARM: Linux, ARMv5, armel (soft-float)
• Raspberry Pi: Linux, ARMv5, armhf (hard-float)
• FreeBSD: x86
• Darwin: OS X Intel, console (and GUI) applications
• Syllable: Syllable OS, x86
• Android: Android, ARMv5
• Android-x86: Android, x86

(Note: This list will increase with time and should therefore be considered as incomplete.)

Hello World!

Red [Title: "Simple hello world script"]
print "Hello World!"

Factorial example

IMPORTANT: These are intended as syntax examples. Until Red has 64-bit support, the integer example will overflow a 32-bit integer very quickly. Changing that to `float!` will go farther, but these are merely to show the syntax of the language.

The following is a factorial example in Red:

Red [Title: "A factorial script"]  ; Note: The title is optional.

factorial: func [
	x [integer!]  ; Giving the type of an argument in Red is optional
][
	either x = 0 [1][x * factorial x - 1]
]

The following is the same factorial example in Red/System (in this very simple case, the source code is very similar to Red's version):

Red/System [Title: "A factorial script"]

factorial: func [
	x       [integer!]                   ; This is compulsory in Red/System
	return: [integer!]                   ; This is compulsory in Red/System
][
	either x = 0 [1][x * factorial x - 1]
]

See also

• Rebol

References

Further reading

• Balbaert, Ivo (May 2018) (in en). Learn Red - Fundamentals of Red. Packt Publishing. ISBN 978-1789130706. 

External links

• Red Programming Language on GitHub
• Redprogramming.com
• on GitHub

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