refine scheme installation instructions

[lambda.git] / how_to_get_the_programming_languages_running_on_your_computer.mdwn

## Identifying your system ##

We'll assume you're using either Mac OS X, or Windows, or Linux.
If you're running **iOS**, you'll have a much harder time (perhaps impossible,
perhaps not) getting this software to run on your machine, and we can't give
you any guidance.

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)

Furthermore, Mac users will 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 <http://www.macports.org/>.
    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.

    There are instructions about how to get Xcode on the [Installing MacPorts](https://www.macports.org/install.php) page.
    Some versions of [Xcode](http://developer.apple.com/xcode.html) are available for free on the Mac App Store.
    Other versions are available through Apple's Developer website (some of these are free, but do require you to
    register with Apple as an "Apple Developer", which involves clicking to accept 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.
    <!--
    The latest version of Xcode to work with 10.5 / Leopard is 3.14; more recent versions (>= 3.2) require 10.6 / Snow Leopard.
    3.2.6 is last version that can be downloaded for free by users of 10.6 / Snow Leopard. (But if they pay, they can use up to Xcode 4.2.)
    Xcode 4.1 was free to all users of 10.7 / Lion. Is Xcode 4.6.x still available for free? Are Xcode 5.x and/or 6.x available for free?
    -->

*   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 <http://www.cygwin.com/> 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. (**Most Windows users will be in this group.**)
    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.


**For everyone**, 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 also called "x64" or "amd64" or "IA-64" or sometimes just "64-bit". (Note that these *aren't* "x86" machines, even though "x86\_64" starts with those letters.)
*   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.

On Linux or Mac OS X, you can open a terminal and type `uname -m`. If the
result is "x86\_64", then you've got x64/64-bit. If it's "i386" or something
like that, then you've got x86/32-bit. I think that Mac OS Xs from 10.7 / Lion
forward have all been x86\_64-only.

On Windows,
[here is a page that can help you figure this out](http://windows.microsoft.com/en-us/windows/32-bit-and-64-bit-windows).
I think that most machines running Windows XP will be x86/32-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.


## 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 (or platform) among others for working with the Scheme 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.
<!-- "racket" used to be mzscheme, "DrRacket" used to be DrScheme -->

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 <http://tryscheme.sourceforge.net/>.

*   **To install in Windows**

    Go to <http://racket-lang.org/download/>. 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 <http://racket-lang.org/download/>. 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

    <!-- mzscheme v4.1.5, from March 2009; latest mzscheme is 4.2.5, from April 2010 -->

    If you want the GUI components, I think you'll need to use the
    "Mac/without MacPorts" installation options above. Or you could try the Chicken Scheme implementation instead of Racket. This is more current.
    To do that, type:

        sudo port install chicken readline

    <!-- chicken v4.8.0.2, from Feb 2013; latest available is 4.9.0.1, from Nov 2014 -->

    Whether you use mzscheme or Chicken, I recommend also typing:

        sudo port install rlwrap

    then if you ever use the command-line program `mzscheme` (or `racket`, for that matter), you should start it by typing `rlwrap mzscheme` (or whatever). 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 <http://racket-lang.org/download/>.
    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` (or whatever). 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 <http://try.ocamlpro.com/>.

*   **To install in Windows**

    Go to <http://caml.inria.fr/download.en.html>.
    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 <http://projects.camlcity.org/projects/findlib.html>.

*   **To install on Mac without MacPorts**

    To install OCaml 3.12 (just released this summer), go to
    <http://caml.inria.fr/download.en.html>
    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
    <http://download.camlcity.org/download/findlib-1.2.6.tar.gz>.
    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
    <http://caml.inria.fr/download.en.html>.
    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
    <http://download.camlcity.org/download/findlib-1.2.6.tar.gz>.
    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:
    <https://godirepo.camlcity.org/svn/lib-findlib/trunk/INSTALL>.

    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 <http://tryhaskell.org/>.

sudo apk-get install haskell-platform

<https://github.com/pittsburgh-haskell/haskell-installation>

<https://www.haskell.org/platform>

Getting started: <https://wiki.haskell.org/Haskell_in_5_steps>