--- a/slides/slides03.tex Wed Nov 23 13:32:01 2016 +0000
+++ b/slides/slides03.tex Thu Nov 24 01:44:38 2016 +0000
@@ -3,6 +3,7 @@
\usepackage{../graphics}
\usepackage{../langs}
%\usepackage{../data}
+\usepackage[export]{adjustbox}
\hfuzz=220pt
@@ -18,7 +19,7 @@
\newcommand{\bl}[1]{\textcolor{blue}{#1}}
% beamer stuff
-\renewcommand{\slidecaption}{PEP (Scala) 02, King's College London}
+\renewcommand{\slidecaption}{PEP (Scala) 03, King's College London}
\begin{document}
@@ -28,7 +29,7 @@
\frametitle{%
\begin{tabular}{@ {}c@ {}}
\\[5mm]
- \huge PEP Scala (2)
+ \huge PEP Scala (3)
\end{tabular}}
\normalsize
@@ -44,50 +45,171 @@
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\begin{frame}[t]
-\frametitle{\begin{tabular}{c}Why Scala?\end{tabular}}
-
+\begin{frame}[c, fragile]
+\frametitle{The Joy of Immutability}
\begin{itemize}
-\item \large {\bf You can avoid \textcolor{blue}{\texttt{null}}}:
-\end{itemize}
-
+\item If you need to manipulate some data in a list say, then you make
+ a new list with the updated values, rather than revise the original
+ list. Easy!\medskip
-\begin{textblock}{6}(1,5)
- \begin{bubble}[10.5cm]\small
- ``I call it my billion-dollar mistake. It was the invention of
- the null reference in 1965. At that time, I was designing the
- first comprehensive type system for references in an object
- oriented language (ALGOL W). My goal was to ensure that all use
- of references should be absolutely safe, with checking performed
- automatically by the compiler. But I couldn't resist the
- temptation to put in a null reference, simply because it was so
- easy to implement. This has led to innumerable errors,
- vulnerabilities, and system crashes, which have probably caused
- a billion dollars of pain and damage in the last forty years.''
- \hfill Sir Tony (Hoare)
-\end{bubble}
-\end{textblock}
+ {\small
+ \begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-1mm]
+ val old_list = List(1, 2, 3, 5)
+ val new_list = 0 :: old_list
+ \end{lstlisting}}
-\begin{textblock}{5}(11.8,1)
-\includegraphics[scale=0.20]{hoare.jpg}\\
-\end{textblock}
-
+\item You do not have to be defensive about who can access the data
+ (concurrency, lazyness).
+\end{itemize}
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\begin{frame}[c]
-\frametitle{\huge\textbf{\texttt{return}}}
+\begin{frame}[t]
+\frametitle{Email: Hate 'val'}
+
+\mbox{}\\[-25mm]\mbox{}
+
+\begin{center}
+ \begin{bubble}[10.5cm]
+ Subject: \textbf{Hate '\textbf{\texttt{val}}'}\hfill 01:00 AM\medskip\\
+
+ Hello Mr Urban,\medskip\\
+
+ I just wanted to ask, how are we suppose to work
+ with the completely useless \textbf{\texttt{val}}, that can’t be changed ever? Why is
+ this rule active at all? I’ve spent 4 hours not thinking on the
+ coursework, but how to bypass this annoying rule. What’s the whole
+ point of all these coursework, when we can’t use everything Scala
+ gives us?!?\medskip\\
-\begin{center}\LARGE
-you should never use it
+ Regards.\\
+ \mbox{}\hspace{5mm}\textcolor{black!50}{<<deleted>>}\\
+ \end{bubble}
+\end{center}
+
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[c]
+
+\mbox{}\\[-25mm]\mbox{}
+
+\begin{center}
+ \begin{bubble}[10.5cm]
+ Subject: \textbf{Re: Hate '\textbf{\texttt{val}}'}\hfill 01:02 AM\bigskip\bigskip\\
+
+ \textcolor{black!70}{
+ \textit{\large<<my usual rant about fp\ldots\\ concurrency bla bla\ldots{} better programs
+ yada>>}}\bigskip\bigskip\bigskip
+
+ PS: What are you trying to do where you desperately want to use \texttt{var}?
+ \end{bubble}
\end{center}
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[c,fragile]
+
+\begin{textblock}{6}(0.5,0.5)
+\begin{bubble}[11.5cm]
+ \small
+ Subject: \textbf{Re: Re: Hate '\textbf{\texttt{val}}'}\hfill 01:04 AM\medskip\\
+
+ \textbf{Right now my is\_legal function works fine:}
+
+\footnotesize\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-1mm]
+ def is_legal(dim: Int, path: Path)(x: Pos): Boolean = {
+ var boolReturn = false
+ if(x._1 > dim || x._2 > dim || x._1 < 0 || x._2 < 0) {
+ else { var breakLoop = false
+ if(path == Nil) { boolReturn = true }
+ else { for(i <- 0 until path.length) {
+ if(breakLoop == false) {
+ if(path(i) == x) {
+ boolReturn = true
+ breakLoop = true
+ }
+ else { boolReturn = false }
+ } else breakLoop
+ }
+ }
+ boolReturn
+ }
+\end{lstlisting}
+\end{bubble}
+\end{textblock}
+
+\begin{textblock}{6}(8.2,11.8)
+\begin{bubble}[5.5cm]\footnotesize\bf
+\ldots{}but I can’t make it work with boolReturn being val. What approach would
+you recommend in this case, and is using var in this case justified?
+\end{bubble}
+\end{textblock}
+
+\only<2>{
+\begin{textblock}{6}(0.3,11.8)
+ \begin{bubble}[3.1cm]
+ \textbf{Me:} \includegraphics[scale=0.08, valign=t]{../pics/throwup.jpg}
+ \end{bubble}
+\end{textblock}}
+
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[t,fragile]
+
+\mbox{}\\[-25mm]\mbox{}
+
+\begin{textblock}{6}(0.5,2)
+ \begin{bubble}[11.5cm]
+ Subject: \textbf{Re: Re: Re: Hate '\textbf{\texttt{val}}'}\hfill 01:06 AM\bigskip\\
+ \small
+
+ OK. So you want to make sure that the \texttt{x}-position is not outside the
+ board....and furthermore you want to make sure that the \texttt{x}-position
+ is not yet in the path list. How about something like\bigskip
+
+\footnotesize\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-1mm]
+ def is_legal(dim: Int, path: Path)(x: Pos): Boolean =
+ ...<<some board conditions>>... && !path.contains(x)
+\end{lstlisting}\bigskip
+
+ \small Does not even contain a \texttt{val}.
+ \end{bubble}
+\end{textblock}
+
+\begin{textblock}{6}(7,12)
+\footnotesize\textcolor{black!50}{(This is all on one line)}
+\end{textblock}
+
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\begin{frame}[t,fragile]
+
+\mbox{}\\[-15mm]\mbox{}
+
+\begin{textblock}{6}(1,3)
+ \begin{bubble}[10.5cm]
+ Subject: \textbf{Re: Re: Re: Re: Hate '\textbf{\texttt{val}}'}\hfill 11:02 AM\bigskip\bigskip\\
+
+ THANK YOU! You made me change my coding perspective. Because of you,
+ I figured out the next one\ldots
+ \end{bubble}
+\end{textblock}
+
+\end{frame}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}[c]
\frametitle{Types}
@@ -122,11 +244,32 @@
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+\begin{frame}[t]
+\frametitle{Where to go on from here?}
+
+\begin{itemize}
+\item Martin Odersky (EPFL)\ldots he is currently throwing out everything
+ and starts again with the dotty compiler for Scala\medskip
+
+\item Elm (\url{http://elm-lang.org})\ldots web applications with style\medskip
+
+\item Haskell, Ocaml, Standard ML, Scheme
+\end{itemize}
+\end{frame}
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}[c]
\frametitle{\begin{tabular}{c}\\[3cm]\alert{Questions?}\end{tabular}}
-\mbox{}
+\mbox{}\footnotesize
+Thanks: ``\it{}By the way - Scala is really getting quite fun
+when you start to get the hang of it\ldots''
+
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\end{document}