## Identifying your system ## We'll assume you're using either Mac OS X, or Windows, or Linux. If you're using **Mac OS X**, take note of what version of the Mac OS you're running. (Under the Apple Menu, select "About this Mac".) * Leopard (10.5) * Snow Leopard (10.6) * Lion (10.7) * Mountain Lion (10.8) * Mavericks (10.9) * Yosemite (10.10) If you're running **iOS**, you probably can't use this software on that machine. (A bit more below.) Furthermore, you'll be in one of two subgroups: * You'll have Apple's Xcode and the independent MacPorts system installed. (Probably you don't. If you don't know what I'm talking about, you don't have these.) If you don't have these, but want to try this route, you can read about the MacPorts system at . This automates the building of Unix-type software on your Mac; it makes it a lot easier to check for dependencies, use more-recent versions of things, and so on. (Though as it happens, MacPorts only has an older version of our chosen implementation of Scheme.) There are also other package management systems available for the Mac, notably Homebrew and Fink. I only know a little bit about them. Xcode is available at . Some versions of this have been available for free, though you do have to register with Apple as an "Apple Developer", which involves accepting a legal agreement with Apple. I have an older version of this installed. If you download a recent version, email me and let me know how the process works so I can tell others. There are instructions about how to get Xcode in the MacPorts installation guide. * Or you won't have those installed. (**Most Mac users will be in this group.**) Then you'll need pre-packaged (and usually pretty GUI) installers for everything. These are great when they're available and kept up-to-date; however sometimes those conditions aren't met. If you're using **Windows**, you'll be in one of two subgroups: * You'll have the Cygwin system installed. This puts a Unix-like layer on top of your Windows system, and makes it easier for you to use the same software everybody else will be using, without its needing as much special-for-Windows treatment. However, many of you won't have this installed. * You won't have Cygwin installed. You might in theory have a different group of compilers installed (MinGW, or Microsoft Visual C++) but we'll assume that the overwhelming majority of users in this group don't have access to a compiler and need pre-packaged installers for everything. If you're using **Linux**, you could be using any one of numerous packaging systems. * We'll give examples using the packaging system shared by Debian and Ubuntu, and we'll assume that those of you using different packaging systems will know how to make the relevant substitutions. You may also want to take note of the output of the "uname -srm" command. On my machine this tells me "Linux 3.12.8-extrastuff x86\_64". That tells me I'm running the x86\_64 (as opposed to the i686 or i386 or whatever) version of Linux, and that I'm running kernel version 3.12.8. **For all of these groups**, a general item to take note of is what "processor architecture" your machine is running. Three of the possibilities are: * One of Intel's i386, i486, i586, i686 architectures. These are collectively known as "x86" or "IA-32" or sometimes just "32-bit". * Intel or AMD's x86\_64 architecture. This is sometimes also called "x64" or "amd64" or "IA-64" or sometimes just "64-bit". * ARM or some other architecture. These are generally lower-powered machines, like iPads. Some of the software we're proposing *might* in principle be capable of running on such machines, but installers don't seem to be available. We'll assume you have access to an x86 or x86\_64 machine. In the Linux example above, I could tell my machine is running x86 because the result of the `uname` command said "i386" at the end. Another machine I have says "x86\_64" at the end. On a Mac, you can also say `uname -m` in a Terminal session, and it will say something like "i386". I think that Mac OS Xs from Lion / 10.7 forward have all been x86\_64-only. On Windows, I don't know how to collect this information. But generally, machines running Windows XP will probably be i386/32-bit (unless it's a version of Windows with "64-bit" or "x64" in its title); machines running Windows Vista or Windows 7 or Windows 8 could be running either x86/32-bit or x64/64-bit. (Update: I found [this Microsoft page](http://windows.microsoft.com/en-us/windows/32-bit-and-64-bit-windows) that may help.) ## PLEASE REPORT PROBLEMS (AND SOLUTIONS!) ## We haven't tested these instructions ourselves, and they're not explicit step-by-step instructions in any case. If you encounter troubles, please email to let us know so that we can amend the instructions to help others. If you figure out how to fix the problem youself (and please do), please also write with suggestions how we can change these instructions to make the process easier and more straightforward for others. ## Getting Scheme ## **Scheme** is one of two or three major dialects of *Lisp*, which is a large family of programming languages. The other dialects are called "Common Lisp" and "Clojure". Scheme is the more clean and minimalist dialect, and is what's mostly used in academic circles. Scheme itself has umpteen different "implementations", which share most of their fundamentals, but have slightly different extensions and interact with the operating system differently. One major implementation is called Racket, and that is what we recommend you use. (A few years back they were called PLT Scheme, but then they changed their name to Racket.) If you're already using or comfortable with another Scheme implementation, though, there's no compelling reason to switch. If for some reason you have problems with Racket, other implementations you could try are [Chicken](http://www.call-cc.org), [Gauche](http://practical-scheme.net/gauche), or [Chibi](https://code.google.com/p/chibi-scheme). The later in that list you go, the more likely it is that you'll have to compile the software yourself. (Thus Mac users will need Xcode.) Racket stands to Scheme in something like the relation Firefox stands to HTML. It's one program among others for working with the language; and many of those programs (or web browsers) permit different extensions, have small variations, and so on. Racket has several components. The two most visible components for us are a command-line interpreter named "racket" and a teaching-friendly editor/front-end named "DrRacket". You will probably be working primarily or wholly in the latter. The current version of Racket is 6.1.1 (released November 2014). * In your web browser: There is a (slow, bare-bones) version of Scheme available for online use at . * **To install in Windows** Go to . Download and install the "Windows x64" version. (Or the "Windows x86" verson if you have an older, 32-bit system.) * **To install on Mac without MacPorts** Go to . Download and install the option for your system, most likely "Macintosh OS X (Intel 64-bit)". * **To install on Mac with MacPorts** Unfortunately, MacPorts doesn't have Racket itself available. It only has an older version from when they still called themselves PLT Scheme. And even then, it only has the command-line program "mzscheme" (what's nowadays called "racket"); it doesn't have the GUI program that corresponds to what's now called "DrRacket". You can install mzscheme by opening a Terminal window and typing: sudo port install mzscheme If you want the GUI components, I think you'll need to use the "Mac/without MacPorts" installation options above. I recommend also typing: sudo port install rlwrap then if you ever use the command-line program `mzscheme` (or `racket`), you should start it by typing `rlwrap mzscheme`. This gives you a nice history of the commands you've already typed, which you can scroll up and down in with your keyboard arrows. * **To install on Linux** Use your packaging system, for example, open a Terminal and type: sudo apt-get install racket It's very likely that your packaging system has some version of Racket available, so look for it. However, if you can't find it you can also install a pre-packaged binary from the Racket website at . Choose the option for your version of Linux (Ubuntu and Debian are available). As above, I recommend you also type: sudo apt-get rlwrap then if you ever use the command-line program `mzscheme` (or `racket`), you should start it by typing `rlwrap mzscheme`. This gives you a nice history of the commands you've already typed, which you can scroll up and down in with your keyboard arrows. ## Getting OCaml ## **Caml** is one of two major dialects of *ML*, which is another large family of programming languages. The other dialect is called "SML" and has several implementations. But Caml has only one active implementation, OCaml or Objective Caml, developed by the INRIA academic group in France. Sometimes we may refer to Caml or ML more generally; but you can assume that what we're talking about always works more specifically in OCaml. It's helpful if in addition to OCaml you also install the Findlib add-on. This will make it easier to install additional add-ons further down the road. However, if you're not able to get that working, don't worry about it much. The current version of OCaml is 4.02.1 (released October 2014). Another instruction page focuses on [OPAM](http://ocaml.org/docs/install.html), also [this](https://opam.ocaml.org). * In your web browser: There is a (slow, bare-bones) version of OCaml available for online use at . * **To install in Windows** Go to . You can probably download and install the "Self installer for the port based on the MinGW toolchain" even if you don't know what MinGW or Cygwin are. Some features of this require Cygwin, but it looks like it should mostly work even for users without Cygwin. At the time of this writing, only an installer for the previous version of OCaml (3.11.0, from January 2010) is available. To install the Findlib add-on, you must have the Cygwin system installed. We assume few of you do, so we're not going to try to explain how to do this. If you want to figure it out yourself, go to the Findlib website at . * **To install on Mac without MacPorts** To install OCaml 3.12 (just released this summer), go to and download and install the "Binary distribution for Mac OS X" To install the Findlib add-on, you'll need the Xcode development tools to compile it yourself. Once you get that far, it's probably easiest for you to install MacPorts and just install things using the MacPorts instructions. (Use the MacPorts version of OCaml, instead of installing the package from the caml.inria.fr website, as described above) However, if you do have Xcode, and want to do without MacPorts, then what you need to do is download Findlib from . Unpack the download, open a Terminal and go into the folder you just unpacked, and type: ./configure make package-macosx This will build an installer package which you should be able to double-click and install. * **To install on Mac with MacPorts** You can install the previous version of OCaml (3.11.2, from January 2010), together with the Findlib add-on, by opening a Terminal and typing: sudo port install ocaml caml-findlib As with Scheme, it's helpful to also have rlwrap installed, and to start OCaml as `rlwrap ocaml`. This gives you a nice history of the commands you've already typed, which you can scroll up and down in with your keyboard arrows. * [More details about installing OCaml on Macs, if needed](http://cocan.org/getting_started_with_ocaml_on_mac_os_x) * **To install on Linux** Use your packaging system, for example, open a Terminal and type: sudo apt-get install ocaml ocaml-findlib That will install a version of OCaml and the Findlib add-on. If for some reason you can't get OCaml through your packaging system, you can go to . Pre-packaged binary installers are available for several Linux systems. If you can't get findlib through your packaging system, you'll need to download it from . and use gcc to compile it yourself. If you don't know how to do that, you probably don't want to attempt this. Here are the INSTALL notes: . As with Scheme, it's helpful to also have rlwrap installed, and to start OCaml as `rlwrap ocaml`. This gives you a nice history of the commands you've already typed, which you can scroll up and down in with your keyboard arrows. ## Getting Haskell ## This last step is less crucial than the others, since we will be focusing primarily on Scheme and OCaml. However we, and the readings you come across, will sometimes mention Haskell, so it might be worth your installing this too, so that you have it available to play around with. Haskell is used a lot in the academic contexts we'll be working through. At one point, Scheme dominated these discussions but now Haskell seems to do that. Haskell's surface syntax differs from Caml, and there are various important things one can do in each of Haskell and Caml that one can't (or can't as easily) do in the other. But these languages also have *a lot* in common, and if you're familiar with one of them, it's generally not hard to move between it and the other. * In your web browser: There is a (slow, bare-bones) version of Haskell available for online use at . sudo apk-get install haskell-platform Getting started: