## 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: * Leopard (10.5) * Snow Leopard (10.6) * Lion (10.7) * Mountain Lion (10.8) * Mavericks (10.9) * Yosemite (10.10) 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.) 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 (see below). The MacPorts system is available 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. * 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 those conditions aren't always 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 (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. ## 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 major dialects of *Lisp*, which is a large family of programming languages. The other dialect is called "Common Lisp." Scheme is the more clean and minimalistic 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 used to be called PLT Scheme, but then a few years ago changed their name to Racket. This is what we recommend you use. (If you're already using or comfortable with another Scheme implementation, though, there's no compelling reason to switch.) 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. * 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** You can install a command-line version of PLT Scheme (dating from early 2009) by opening a Terminal 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. *Will add more information about this soon.*