% Author: Florian Guthmann <florian.guthmann@fau.de>
% URL:    https://wwwcip.cs.fau.de/~oc45ujef/talks/nix/talk.tex
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\RCS$Id: talk.tex,v 1.6 2025/05/26 18:05:16 flo Exp $
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\usepackage{tikz}
\usetikzlibrary{babel, calc, positioning}

\title{Keine Ahnung von Nix}
\subtitle{An Introduction to Nix by the Least Enthusiastic Nix User}
\author{\texttt{\href{https://commenting.onthe.incoherenceofthe.net/@flo}{@flo@commenting.onthe.incoherenceofthe.net}}}
\date{2025-05-22}

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\begin{document}
{
  \setbeamertemplate{footline}{}
  \setbeamertemplate{background}
  {
    \includegraphics[width=\paperwidth]{img/aquinas}
  }
  \frame{\titlepage}
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\part{Prolegomena}
\frame{\partpage{}}

\begin{frame}
  \frametitle{Nixology}
  \begin{center}
    \begin{tikzpicture}[blob/.style = {
        draw=primary, circle,
        inner sep=.1em, minimum size=5em,
        fill=background-alt,
        align=center
      },
      every path/.append style = {double, double distance=1em}]
      \node[blob, minimum size=4em] (nix) {Nix};
      \node[blob] (nixos) at (30:3) {NixOS};
      \node[blob] (nixpkgs) at (150:3) {Nixpkgs};
      \node[blob] (nixl) at (270:3) {Nix\\(Language)};
      \draw (nix) to node[sloped] {\footnotesize{}EST} (nixl);
      \draw (nix) to node[sloped] {\footnotesize{}EST} (nixpkgs);
      \draw (nix) to node[sloped] {\footnotesize{}EST} (nixos);
      \draw (nixpkgs) to node[sloped] {\footnotesize{}NON EST} (nixos);
      \draw (nixos) to node[sloped] {\footnotesize{}NON EST} (nixl);
      \draw (nixl) to node[sloped] {\footnotesize{}NON EST} (nixpkgs);
    \end{tikzpicture}
  \end{center}
\end{frame}

\section{Nix (Language)}
\begin{frame}
  \frametitle{Nix (Language)}
  \begin{center} JSON with functions \(\sim\) Untyped (lazy)
    \(\lambda\)-calculus with records
  \end{center}
\end{frame}

\begin{frame}[fragile]
  \frametitle{Functions}
  \begin{tikzpicture}[remember picture, overlay]
    \node[anchor=north east] at (current page.north east)
    {
      \includegraphics[width=0.25\textwidth]{img/mockingbird}
    };
  \end{tikzpicture}

\begin{semiverbatim}
id = x: x

add = x: y: x + y

omega = x: x x

k = x: y: x

bb = a: b: c: d: a (b c d)
\end{semiverbatim}
\end{frame}

\begin{frame}[fragile]
  \frametitle{\sout{Records} \emph{Attribute Sets}}
\begin{verbatim}
{
  string = "hello";
  integer = 1;
  float = 3.141;
  bool = true;
  list = [ 1 "two" false ];
  attribute-set = {
    a = "hello";
    b = 2;
    c = 2.718;
    d = false;
  }; # comments are supported
}
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
  \frametitle{Derivations}
\begin{verbatim}
derivation {
  name = "hello";
  system = "x86_64-linux";
  builder = "/bin/sh";
  args = [ "-c" "echo foo > $out"];
}
\end{verbatim}
\end{frame}

\begin{frame}[fragile]
\begin{semiverbatim}
$ cat der.nix
derivation \{
  name = "hello";
  system = "x86_64-linux";
  builder = "/bin/sh";
  args = [ "-c" "echo foo > $out"];
\}
$ nix-build der.nix
this derivation will be built:
  /nix/store/\hlbox{hl-primary}{hash}-hello.drv
building '/nix/store/\hlbox{hl-secondary}{hash'}-hello.drv'...
/nix/store/\hlbox{hl-secondary}{hash'}-hello
$ cat /nix/store/\hlbox{hl-secondary}{hash'}-hello
foo
\end{semiverbatim}
\end{frame}

\begin{frame}
  \frametitle{Builder execution}
  \begin{enumerate}
  \item set \texttt{\$PWD} to a temporary directory
  \item clear environment, set according to derivation
  \item execute \texttt{builder} with \texttt{args}, write output to \texttt{\$out}
  \item set \texttt{\$out} to be read-only\ldots
  \end{enumerate}
\end{frame}

\section{Nixpkgs}
\begin{frame}
  \frametitle{Nixpkgs}
  \begin{center}
    A collection of over 120.000 \texttt{nix} packages/derivations
  \end{center}
\end{frame}

\section{NixOS}
\begin{frame}
  \frametitle{NixOS}
  \begin{center}
    A systemd/Linux distribution built on top of \texttt{nixpkgs}
  \end{center}
\end{frame}

\part{Polemics}
\frame{\partpage{}}

\begin{frame}
  \frametitle{Hujjat al-Nix}
  \begin{tikzpicture}[remember picture, overlay]
    \node[anchor=north east] at (current page.north east)
    {
      \includegraphics[width=0.2\textwidth]{img/alghazali}
    };
  \end{tikzpicture}

  \begin{itemize}
  \item<+-> Purely functional package management is a good idea
  \item<+-> Rollbacks are trivial
  \item<+-> Derivations are reproducible\footnote{mostly}
  \end{itemize}
\end{frame}

\begin{frame}
  \frametitle{Annoyances}
  \begin{itemize}
  \item<+-> 120.000 packages --- because \emph{everything} has to be packaged
  \item<+-> Documentation all over the place
  \item<+-> Nix is not a good programming language
  \end{itemize}
\end{frame}

\begin{frame}
  \frametitle{Guix}
  \begin{tikzpicture}[remember picture, overlay]
    \node[anchor=north east] at (current page.north east)
    {
      \reflectbox{\includegraphics[width=0.25\textwidth]{img/averroes}}
    };
  \end{tikzpicture}
  \begin{itemize}
  \item<+-> A \emph{sane} configuration/programming language\footnote{Guile Scheme}
  \item<+-> More unified ecosystem
  \item<+-> Submission to GNU zealots is required
  \item<+-> Noone knows how to pronounce the name
  \end{itemize}
\end{frame}

\begin{frame}[fragile]
  \frametitle{Why I use Nix\{,OS\}}
  \begin{center}
    \begin{tikzpicture}
      \draw[scale=2,domain=-1.35:1.64, smooth, thick, variable=\x] plot ({\x}, {-\x^6 + 3*\x^4 + 0.5*\x^3 - 2*\x^2 });
      \node[circle, fill=secondary] at (1.12, -0.335) {};
    \end{tikzpicture}
  \end{center}
\end{frame}

\begin{frame}
  \frametitle{The Ballad of Frankie Lee and Judas Priest}
  \begin{center}
    \includegraphics[width=.8\textwidth]{img/xkcd}
    {\scriptsize \url{https://xkcd.com/1768}}
  \end{center}
\end{frame}
\end{document}

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