325 lines
No EOL
10 KiB
TeX
325 lines
No EOL
10 KiB
TeX
\documentclass[paper=a4,parskip=half,11pt,english,oneside,open=any,draft=false]{scrreprt}
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\usepackage[utf8]{inputenc}
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\usepackage[T1]{fontenc}
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\usepackage{lmodern}
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\usepackage{babel}
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\usepackage{csquotes}
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\usepackage{listings}
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\usepackage{xcolor}
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\usepackage{textcomp}
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\usepackage{applekeys}
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\usepackage{hyperref}
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\hypersetup{pdfinfo={Title={Hands-On DLang}, Author={Johannes Loher}}}
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\lstdefinestyle{D}{
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language=C,
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emptylines=1,
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breaklines=true,
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basicstyle=\footnotesize\ttfamily,
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keywordstyle=\bfseries\color{green!50!black},
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commentstyle=\itshape\color{white!50!black},
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numbers=left,
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frame=single,
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showstringspaces=false
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}
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\lstdefinestyle{bash}{
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language=bash,
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emptylines=1,
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breaklines=true,
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basicstyle=\footnotesize\ttfamily,
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numbers=left,
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frame=single,
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showstringspaces=false
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}
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\setkomafont{descriptionlabel}{\normalfont}
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\begin{document}
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\title{Hands-On DLang}
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\author{Johannes Loher}
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\date{\today}
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\maketitle
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\tableofcontents
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\chapter{Setup}
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\section{Installing DMD and DUB}
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\subsection{OS X}
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\subsubsection{Installing with Homebrew (recommended)}
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\begin{lstlisting}[style=bash]
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brew install dmd
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brew install dub
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\end{lstlisting}
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\subsubsection{Installing locally using the install script}
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\begin{lstlisting}[style=bash]
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curl -fsS https://dlang.org/install.sh | bash -s dmd
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echo "~/.dlang/dmd-2.079.0/activate" >> ~/.profile # Add dmd and dub to PATH on starting a bash shell
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\end{lstlisting}
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\subsubsection{Installing using the installer}
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\begin{enumerate}
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\item Download \url{http://downloads.dlang.org/releases/2.x/2.079.0/dmd.2.079.0.dmg}.
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\item Open \texttt{dmd.2.079.0.dmg}.
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\item Run \texttt{DMD2.pkg} (you might need to activate the \enquote{allowinstalling applications from unverified developers} option in your security settings) and install with the default settings.
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\end{enumerate}
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\subsection{Windows}
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\begin{enumerate}
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\item Download \url{http://downloads.dlang.org/releases/2.x/2.079.0/dmd-2.079.0.exe}.
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\item Run \texttt{dmd-2.079.0.exe} and install with the default settings (this will also install Visual Studio if you do not have it installed yet).
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\end{enumerate}
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\section{Recommended editor setup}
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Visual Studio Code is the recommended editor, because it has the best D integration at the moment.
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If you want to use another editor or IDE, that is perfectly fine.
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However, instructions will only be provided for Visual Studio Code.
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\subsection{Installation of Visual Studio Code}
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Download and install Visual Studio Code from here: \url{https://code.visualstudio.com/}. OS X users can also install it using Homebrew:
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\begin{lstlisting}[style=bash]
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brew tap caskroom/cask
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brew cask install visual-studio-code
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\end{lstlisting}
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\subsection{Extension setup}
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\begin{enumerate}
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\item Open the Extension view in the sidebar:
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\begin{tabular}{ll}
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OS X: & \cmdkey{} + \shiftkey{} + X\\
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Windows: & \ctlkey{} + \shiftkey{} + X
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\end{tabular}
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\item Install the extension \enquote{D Programming Language (code-d)} (requires that git is installed).
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\item Restart Visual Studio Code.
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\end{enumerate}
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\chapter{Basics}
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\section{Hello World}
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\begin{lstlisting}[style=D]
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import std.stdio;
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void main() {
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writeln("Hello World");
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}
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\end{lstlisting}
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\section{Imports and modules}
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D has the concept of \emph{modules} and \emph{packages}.
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By importing a certain module with the \texttt{import} statement,all public symbols from module become available.
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The standard library, called Phobos, is located in the \texttt{package}.
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E.g. in order to import the \texttt{file} module from Phobos, you would write:
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\begin{lstlisting}[style=D]
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import std.file;
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\end{lstlisting}
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\subsection{Selective imports}
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It is possible (and often good style) to import symbols selectively from a module:
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\begin{lstlisting}[style=D]
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import std.stdio: writeln, writefln;
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\end{lstlisting}
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\subsection{Scoped imports}
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It is not necessary to place imports at the beginning of a file.
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They can be located anywhere in the code.
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If they appear inside a certain scope (delimited by braces), the imported symbols are only available inside that scope.
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Here is an alternative version of the hello world program:
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\begin{lstlisting}[style=D]
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void main()
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{
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import std.stdio: writeln;
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writeln("Hello World");
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}
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/* writeln is not available outside of the main function */
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\end{lstlisting}
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\subsection{Imports match files and directories}
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The module system is entirely based on files.
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E.g. \texttt{my.thing} refers to a file \texttt{thing.d} in the folder \texttt{my/}.
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\section{Basic Types}
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D has the following basic types:
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\begin{tabular}{ll}
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\texttt{bool} & 8-bit\\
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\texttt{byte}, \texttt{ubyte}, \texttt{char} & 8-bit\\
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\texttt{short}, \texttt{ushort}, \texttt{wchar} & 16-bit\\
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\texttt{int}, \texttt{uint}, \texttt{dchar}, \texttt{float} & 32-bit\\
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\texttt{long}, \texttt{ulong}, \texttt{double} & 64-bit\\
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\texttt{real} & $\ge$ 64-bit (generally 64-bit, but 80-bit on Intel x86 32-bit)
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\end{tabular}
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\texttt{char} represents UTF-8 characters, \texttt{wchar} represents UTF-16 characters, and \texttt{dchar} represents UTF-32 characters.
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\subsection{Type conversion}
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For integer types, automatic type conversion is only allowed if no precision is lost (e.g. \texttt{int} to \texttt{long}).
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All conversion between floating point types are allowed (e.g. \texttt{double} to \texttt{float}).
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Manual type conversion is achieved with the \texttt{cast} expression:
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\begin{lstlisting}[style=D]
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long a = 1;
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int b = cast(int) a;
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\end{lstlisting}
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\subsection{Type properties}
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All types have a property \texttt{.init} to which variables of that type are initialized, if they are not initialized explicitly.
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For integer types, this is \texttt{0} and for floating point types it is \texttt{nan}.
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Every type also has a \texttt{.stringof} property which yields its name as a string.
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Integer types have some more properties:
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\begin{tabular}{ll}
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\texttt{.max} & The maximum value the type can hold\\
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\texttt{.min} & The minimum value the type can hold
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\end{tabular}
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And so do floating point types:
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\begin{tabular}{ll}
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\texttt{.max} & The maximum value the type can hold\\
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\texttt{.min\_normal} & The smallest representable normalized value that is not \texttt{0}\\
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\texttt{.nan} & NaN value\\
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\texttt{.infinity} & Infinity value\\
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\texttt{.dig} & number of decimal digits of precisions\\
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\texttt{.mant\_dig} & number of bits in mantissa\\
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\dots
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\end{tabular}
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\subsection{Indexing}
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For indexing, usually the alias type \texttt{size\_t} is used, which is large enough to represent an offset into all addressable memory.
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\section{Variable declarations}
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Variables are declared by writing the type followed by the variable name:
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\begin{lstlisting}[style=D]
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int myVar;
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\end{lstlisting}
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They can also be explicitly initialized:
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\begin{lstlisting}[style=D]
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int myVar = 42;
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\end{lstlisting}
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It is also possible to declare several variables at once:
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\begin{lstlisting}[style=D]
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int myVar, someOtherVar;
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\end{lstlisting}
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D has automatic type deduction, so when explicitly initializing a variable, it is not necessary to mention the type.
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Instead we can use the \texttt{auto} keyword:
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\begin{lstlisting}[style=D]
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auto myVar = 42;
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\end{lstlisting}
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Here is a combination of the above notations:
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\begin{lstlisting}[style=D]
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auto myInt = 42, myFloat = 4.2f;
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\end{lstlisting}
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\section{Functions}
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The basic syntax for functions is very similar to C:
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\begin{lstlisting}[style=D]
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int add(int lhs, int rhs) {
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return lhs + rhs;
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}
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\end{lstlisting}
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\subsection{Return type deduction}
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A functions return type can be defined to be \texttt{auto}.
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In this case, the return type will be infered.
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Multiple return statements are possible, but must return compatible types.
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\begin{lstlisting}[style=D]
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auto add(int lhs, int rhs) { // returns `int`
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return lhs + rhs;
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}
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auto lessOrEqual(int lhs, int rhs) { // returns `double`
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if (lhs <= rhs)
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return 0;
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else
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return 1.0;
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}
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\end{lstlisting}
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\subsection{Default arguments}
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Those also work the same as in C and other languages:
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\begin{lstlisting}[style=D]
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void plot(string msg, string color = "red") {
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/* ... */
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}
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plot("D rocks");
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plot("D rocks", "blue");
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\end{lstlisting}
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\subsection{Local functions}
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It is possible to define functions locally (even inside other functions).
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Those functions are not visible outside their parents scope.
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\begin{lstlisting}[style=D]
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void fun() {
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int local = 10;
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int fun_secret() {
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local++; // that's legal
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}
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/* ... */
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}
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static assert(!__traits(compiles, fun_secret())); // fun_secret is not visible here
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\end{lstlisting}
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\section{Control flow}
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\subsection{if\ldots{}else}
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Very similar to how it is defined in other languages:
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\begin{lstlisting}[style=D]
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if (a == 5) {
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writeln("Condition is met");
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} else if (a > 10) {
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writeln("Another condition is met");
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} else {
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writeln("Nothing is met!");
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}
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\end{lstlisting}
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\subsection{switch\ldots{}case}
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Also very similar to how it is defined in other languages, but for it works for integer types, bools and strings (which will be covered later).
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\begin{lstlisting}[style=D]
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string myString;
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/* ... */
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switch(myString) {
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case "foo":
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writeln("Cool, myString was \"foo\"");
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break;
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default:
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writeln("Meh, myString was something boring");
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break;
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}
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\end{lstlisting}
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For integer types, it is also possible to define ranges:
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\begin{lstlisting}[style=D]
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int c = 5;
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switch(c) {
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case 0: .. case 9:
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writeln(c, " is within 0-9");
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break; // necessary!
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case 10:
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writeln("A Ten!");
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break;
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default: // if nothing else matches
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writeln("Nothing");
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break;
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}
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\end{lstlisting}
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\subsection{Loops}
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\texttt{while}-, \texttt{do\ldots{}while}- and classical \texttt{for}-loops all work the same as in C++/Java etc.
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\subsubsection{Breaking out of outer loops}
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As usual, you can break out of a loop immediately by using the \texttt{break} keyword. Additionally, you can also break out of outer loops by using labels:
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\begin{lstlisting}[style=D]
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outer: for (int i = 0; i < 10; ++i) {
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for (int j = 0; j < 5; ++j) {
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/*...*/
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break outer; // breaks out of the outer loop
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}
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}
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\end{lstlisting}
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\end{document} |