source: project/promotional/flyer/flyer.tex @ 21150

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%% A flyer for promoting Chicken Scheme!
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\begin{document}

\begin{center}
  \Huge\textbf{Chicken Scheme}\\
  \normalsize\textsc{``A practical and portable Scheme system''}
  \vskip 0pt plus 1fill
  \includegraphics[height=0.8\textwidth]{chicken-colored-no-text}
  {\large \bf http://www.call-cc.org}
  \vskip 0pt plus 1fill
\end{center}


\section{What is Chicken Scheme?}

Chicken is a \emph{robust} and \emph{mature} compiler for the
programming language \emph{Scheme}. Chicken has been around for over
10 years now, and has a growing group of dedicated users.

The system compiles to \emph{C}, which allows it to generate
\emph{fast, portable code}. For easy development it also includes a
powerful interpreter!

Chicken is above all a \emph{practical} system; there are literally
\emph{hundreds} of extension libraries (known as ``eggs'') available
to help you get some real work done!  There are extensions for web
development, concurrency and parallelism, cryptography, scientific
computing and much, much more.

All of the major platforms are supported, including GNU/Linux, the
BSDs, MacOS X and Windows.

\section{What is Scheme?}

Scheme is a truly \emph{elegant and minimal} programming language
which directly descends from Lisp, the \emph{second oldest}
high level programming language still in use. But don't be fooled
by that: It's still as fresh today as when it was first created!

\begin{center}
\includegraphics[angle=-90,width=8cm]{different}
\end{center}

It has very simple syntax so it is \emph{easy to learn}. This also
makes it a very powerful tool: writing extensions to the language can
be done right from \emph{within} the language, allowing you to
\emph{mold the language} to better fit your program's
domain. User-added functionality is treated no different from
``built-in'' functionality.

Scheme is well-known as a \emph{functional} programming language, but
it's more accurately described as a \emph{multi-paradigm} language.
Sure, you can program in a functional style, but also in all flavors
of object-oriented, logical, distributed and even imperative styles.
If tomorrow a new cool style of programming is invented, Schemers
won't need to switch languages. Instead, they can just add it to their
favorite language!

\pagebreak
\section{So, why Chicken and not {\mdseries\itshape$<$insert~Scheme~here$>$?}}

Scheme is such a minimalist and easy to parse language that there are
\emph{thousands} of implementations. However, implementing a
\emph{good} Scheme is nontrivial. Of the implementations that are not
toys, we prefer Chicken because it:

\begin{itemize}
\item sticks to the original minimalist spirit of Scheme
\item produces \emph{fast} code
\item has a growing number of useful libraries for real-world tasks
\item integrates very easily with C
\item has been actively maintained for more than 10 years!
\item has an energetic and enthousiastic community!
\end{itemize}

\section{What is Chicken Scheme used for?}

As Scheme is a general purpose language the applications written in
Chicken Scheme are boundless:

As it is so easy to reuse existing libraries with Chicken Scheme the
lisp way, Chicken is a great prototyping platform!

Others tend to write their system administrative tasks in Chicken.

Database insertion, testing and applications can be done easily with
all the major (open source) databases supported.

Easy as pie web applications using Chicken Scheme's webserver
\emph{spiffy} and the webframework \emph{awful} to deploy concisely
written but powerful web applications.

Use the same technology to compile static pages using \emph{hyde}.

Visualize your data using an easy X11 interface, SDL, OpenGL or PDF
extensions!


\section{Show me some examples!}

\subsection{Hello world}

How boring can it be?

\begin{schemedisplay}
(print "Hello, world!")
\end{schemedisplay}

\subsection{Obligatory factorial program}

Slightly less boring than the hello world program:

\begin{schemedisplay}
(define fac
  (lambda (n)
    (if (= n 0)
        1
        (* n (fac (- n 1))))))

(print (fac (list-ref (argv) 2)))
\end{schemedisplay}

\subsection{Integrating Scheme with C}

\begin{schemedisplay}
(define log10
  (lambda (x)
    (/ (log x) (log 10))))

;; The same using log10 from C:
(foreign-declare "#include <math.h>")

(define log10-from-c
  (foreign-lambda* double ((double x))
    "double y;"
    "y = log10(x);"
    "C_return(y);"))

;; Shorter versions:
(define (log10 x) (/ (log x) (log 10)))
(define log10-from-c
  (foreign-lambda double "log10" double))
\end{schemedisplay}

% The example is a little contrived and maybe not too convincing

As you can see, calling C functions is quite easy.  If you have longer
C code, you can also write your functions in a separate C file and
compile those against your Chicken program. You can just call those
functions from Chicken.

\section{Cool, I want to get started!}

Great to have you on board! Chances are your operating system already
packages Chicken Scheme. Try that first. Once you have it installed,
you can try some code with the interpreter \emph{csi}.

\begin{verbatim}
$ csi

CHICKEN
(c)2008-2010 The Chicken Team
(c)2000-2007 Felix L. Winkelmann
Version 4.6.2 
openbsd-unix-gnu-x86 [ manyargs dload ptables ]
compiled 2010-10-18 on athene.my.domain (OpenBSD)

#;1> (print "Welcome to Chicken Scheme!")
Welcome to Chicken Scheme!
#;2> (* 3 (+ 3 4) (/ 4 2))
42
#;3> ,q ; quits
\end{verbatim}

If you aren't familiar with scheme yet, you can check out the
extensive list of books at {\tt http://www.schemers.org/}

For Chicken Scheme specific documentation, try our wiki. If you want
to be kept up to date with developments in chicken you can read a
weekly summary called the \emph{Chicken Gazette}.

For Chicken Scheme specific questions there is a newbie friendly
mailing list \emph{chicken-users@nongnu.org}.

The Chicken Team is also reachable on Freenode's IRC, channel
\#chicken.

\pagebreak

\section{Chicken Scheme on the net}
\begin{tabular}{ll}
Main site:& {\tt http://www.call-cc.org/}\\
Gazette:& {\tt http://gazette.call-cc.org}\\
Code:& {\tt http://code.call-cc.org/}\\
Chat: &{\tt \#chicken at irc.freenode.org}\\
Documentation:& {\tt http://wiki.call-cc.org/}\\
About Scheme:& {\tt http://www.schemers.org/}\\
\end{tabular}

\vskip 5cm

\begin{center}
\includegraphics[width=4cm]{continuation_guild_fighters}
\end{center}


\vskip 0pt plus 1fill 
{\small The Chicken Logo has been made by Joshua Griffith. The other images are drawn by Conrad Barski, used with his kind permission. Also have a look at his book ``Land of Lisp'' \emph{http://landoflisp.com}}

{\footnotesize
\hbox to \hsize{\hss Last updated October 2010\@.} 
\par}


\end{document}