From 5aa542280e58ddaabd84f75665702c25f11cc27d Mon Sep 17 00:00:00 2001 From: iArnold Date: Wed, 29 Jan 2014 16:14:56 +0100 Subject: Create red.html.markdown --- red.html.markdown | 143 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 143 insertions(+) create mode 100644 red.html.markdown (limited to 'red.html.markdown') diff --git a/red.html.markdown b/red.html.markdown new file mode 100644 index 00000000..cfe14c9b --- /dev/null +++ b/red.html.markdown @@ -0,0 +1,143 @@ +--- +name: Red +category: language +language: Red +filename: learnred.red +contributors: + - ["Arnold van Hofwegen", "https://github.com/iArnold"] +--- + + +Red was created out of the need to get work done, and the tool the author wanted to use, the language of REBOL, had a couple of drawbacks. +It was not Open Sourced at that time and it is an interpreted language, what means that it is on average slow compared to a compiled language. + +Red, together with its C-level dialect Red/System, provides a language that covers the entire programming space you ever need to program something in. +Red is a language heavily based on the language of REBOL. Where Red itself reproduces the flexibility of the REBOL language, the underlying language Red will be built upon, +Red/System, covers the more basic needs of programming like C can, being closer to the metal. + +Red will be the worlds first Full Stack Programming Language. This means that it will be an effective tool to do (almost) any programming task on every level +from the metal to the meta without the aid of other stack tools. +Furthermore Red will be able to cross-compile Red source code without using any GCC like toolchain +from any platform to any other platform. And it will do this all from a binary executable that is supposed to stay under 1 MB. + +Ready to learn your first Red? + +``` +Red + +; Single-line comments start with a semicolon ';' + +comment { + Multi-line comments + look like this. +} + +; Import files with #include and filenames start with a % sign +#include %includefile.red + +; Your program's entry point is the first executable code that is found +; no need to restrict this to a 'main' function. + +; Valid variable names start with a letter and can contain numbers, +; variables containing only capital A thru F and numbers and ending with 'h' are +; forbidden, because that is how hexadecimal numbers are expressed in Red and +; Red/System. + +; assign a value to a variable using a colon ':' +my-name: "Red" +reason-for-using-the-colon: {This makes the equality sign '=' exclusively usable for comparisons purposes, thus speeding up the original Rebol interpreter.} +is-this-name-valid?: true + +; print output using print, or prin for printing without a newline or linefeed at the ; end of the printed text. + +prin " My name is " print my-name +My name is Red + +print ["My name is " my-name lf] +My name is Red + +; In case you haven't already noticed: statements do NOT end with a semicolon ;-) + +; +; Datatypes +; +; If you know Rebol, you probably have noticed it has lots of datatypes. Red +; does not have yet all those types, but as Red want to be close to Rebol it +; will have a lot of datatypes. +; You can recognize types by the exclamation sign at the end. But beware +; names ending with an exclamation sign are allowed. +; Some of the available types are integer! string! block! + +; Declaring variables before using them? +; Red knows by itself what variable is best to use for the data you want to use it +; for. +; A variable declaration is not always necessary. +; It is considered good coding practise to declare your variables, +; but it is not forced upon you by Red. +; You can declare a variable and specify its type. a variable's type determines its +; size in bytes. + +; Variables of integer! type are usually 4 bytes or 32 bits +my-integer: 0 +; Red's integers are signed. No support for unsigned atm but that will come. + +; To find out the type of variable use type? +type? my-integer +integer! + +; chars are guaranteed to be 1 byte +; A string can be cast to a character +empty-string: "" +a-string: to-string #"a" + +i2: 1 + i1: 1 + +; Arithmetic is straightforward +i1 + i2 ; result 3 +i2 - i1 ; result 1 +i2 * i1 ; result 2 +i1 / i2 ; result 0 (0.5, but truncated towards 0) + +; Comparison operators are probably familiar, and unlike in other languages you +; only need a single '=' sign for comparison. +; There is a boolean like type in Red. It has values true and false, but also the +; values on/off or yes/no can be used + +3 = 2 ; => false +3 != 2 ; => true +3 > 2 ; => true +3 < 2 ; => false +2 <= 2 ; => true +2 >= 2 ; => true + +; +; Control Structures +; @TBD + +; +; Functions +; +; In Red almost everything can be seen as a function. Even the IF returns a value. + +; Function declaration syntax: +; function-name: function [][] +twice: function [a [integer!] /one return: [integer!]][ + c: 2 + a: a * c + either one [a + 1][a] +] + + + +``` + +## Further Reading + +The main source for information about Red is [the Red language homepage](http://www.red-lang.org). + +To learn more about Rebol and Red join the [chat on StackOverflow](http://chat.stackoverflow.com/rooms/291/rebol-and-red). +(You will need 20 points to chat but if you ask questions about Red or Rebol we will help you get those points). + +Maybe you want to try Red right away? That is possible on the [try Rebol and Red site](http://tryrebol.esperconsultancy.nl). + +You can also learn Red by learning [Rebol](http://www.rebol.com/docs.html). -- cgit v1.2.3