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Binary file cws/main_cw01.pdf has changed
Binary file cws/main_cw02.pdf has changed
--- a/cws/main_cw02.tex Mon Nov 14 12:04:21 2022 +0000
+++ b/cws/main_cw02.tex Thu Nov 17 11:34:50 2022 +0000
@@ -213,7 +213,28 @@
where \pcode{secrets} is the list generated under Task 1.
In all cases above the iscore of the resulting secrets is 0, but this does not need to be the case
-in general.\\
+in general.
+
+\color{red}
+ Note that the template gives as type for \texttt{evil}:
+
+ \begin{center}
+ \texttt{def evil(secrets: List[String], word: String) = ???}
+ \end{center}
+
+ where the return type is left unspecified. This return type is not needed when
+ functions are not recursive---\texttt{evil} is meant to be just a wrapper that
+ calls \texttt{lowest} with appropriate default arguments and returns whatever
+ \texttt{lowest} returns. Therefore a return type is not needed. But a slightly
+ more accurate template definition for \texttt{evil} is:\medskip\medskip
+
+ \begin{minipage}{1.05\textwidth}
+ \begin{center}
+ \texttt{def evil(secrets: List[String], word: String) : List[String] = ???}
+ \end{center}
+ \end{minipage}\medskip\medskip
+
+ where also the return type is explicitly given.\\\color{black}
\mbox{}\hfill [1.5 Marks]
\item[(6)] The secrets generated in Task 5 are the ones with the lowest score
@@ -249,6 +270,14 @@
rank(frequencies(secrets), "fuzzy") => 4.898735738513722
\end{lstlisting}
+ \color{red}
+ The return type for \texttt{rank} is \texttt{Double}:
+
+ \begin{center}
+ \texttt{def rank(frqs: Map[Char, Double], s: String) : Double = ???}
+ \end{center}
+ \color{black}
+
Finally, implement a function \pcode{ranked_evil} that selects from the output of \pcode{evil}
the string(s) which are highest ranked in evilness.
@@ -263,6 +292,14 @@
This means if the user types in "abbey" then the most evil word to choose as secret is ``whizz'' (according to
our calculations). This word has a zero \pcode{iscore} and the most obscure letters.
+\color{red}
+ The return type for \texttt{ranked\_evil} is \texttt{List[String]}:
+
+ \begin{center}
+ \texttt{def ranked\_evil(secrets: List[String], word: String) : List[String] = ???}
+ \end{center}
+ \color{black}
+
%
%\color{red}
%\section*{Correction with \texttt{ranked\_evil}}
Binary file cws/main_cw03.pdf has changed
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Binary file cws/main_cw05.pdf has changed
--- a/main_solution3/re.scala Mon Nov 14 12:04:21 2022 +0000
+++ b/main_solution3/re.scala Thu Nov 17 11:34:50 2022 +0000
@@ -113,7 +113,6 @@
//println(simp(((CHAR('a') | ZERO) ~ ONE) |
// (((ONE | CHAR('b')) | CHAR('c')) ~ (CHAR('d') ~ ZERO))))
-
// (7)
def ders (s: List[Char], r: Rexp) : Rexp = s match {
@@ -191,3 +190,12 @@
}
+
+
+
+
+/*
+// if nullable(r1)
+ ALTs(SEQs(der(c, r1)::rs)::(rs filter what is nullable) .map(der(c,_)))
+
+*/
\ No newline at end of file
--- a/main_testing3/re_test.sh Mon Nov 14 12:04:21 2022 +0000
+++ b/main_testing3/re_test.sh Thu Nov 17 11:34:50 2022 +0000
@@ -200,7 +200,7 @@
if [ $tsts -eq 0 ]
then
echo -e " val EVIL = SEQ(STAR(STAR(CHAR('a'))), CHAR('b'))" >> $out
- echo -e " ders(\"aaaaa\".toList, EVIL) == SEQ(SEQ(STAR(CHAR('a')),STAR(STAR(CHAR('a')))),CHAR('b'))" >> $out
+ echo -e " ders(\"aaaaa\".toList, EVIL) == SEQs(List(STAR(CHAR('a')), STAR(STAR(CHAR('a'))), CHAR('b')))" >> $out
echo -e " ders(List('b'), EVIL) == ONE" >> $out
echo -e " ders(\"bb\".toList, EVIL) == ZERO" >> $out
echo -e " matcher(EVIL, \"a\" * 5 ++ \"b\") == true" >> $out
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/wsheets/wsh02.tex Thu Nov 17 11:34:50 2022 +0000
@@ -0,0 +1,110 @@
+% !TEX program = xelatex
+\documentclass{article}
+\usepackage{../styles/style}
+\usepackage{../styles/langs}
+\usepackage{tikz}
+\usepackage{pgf}
+\usepackage{marvosym}
+\usepackage{boxedminipage}
+
+\lstset{escapeinside={/*!}{!*/}}
+\newcommand{\annotation}[1]{\hfill\footnotesize{}#1}
+
+\usepackage{menukeys}
+
+
+% Exact colors from NB
+\usepackage[breakable]{tcolorbox}
+\definecolor{incolor}{HTML}{303F9F}
+\definecolor{outcolor}{HTML}{D84315}
+\definecolor{cellborder}{HTML}{CFCFCF}
+\definecolor{cellbackground}{HTML}{F7F7F7}
+
+
+
+\begin{document}
+\fnote{\copyright{} Christian Urban, King's College London, 2022}
+
+\section*{Scala Worksheet 2}
+
+
+
+\subsection*{Task 1 (Options)}
+
+Get familiar with constructing strings and printing strings
+(i.e.~\texttt{println}, \texttt{mkString}, \texttt{toString}, \ldots)
+
+\begin{lstlisting}[numbers=none]
+scala> List(7,2,3,4,5,6).find(_ < 4)
+scala> List(5,6,7,8,9).find(_ < 4)
+scala>
+\end{lstlisting}
+
+\subsection*{Task 2 (URLs / Files)}
+
+ALso Try
+
+\begin{lstlisting}[numbers=none]
+scala>
+scala>
+scala>
+\end{lstlisting}
+
+\subsection*{Task 3 (Higher-Order Functions)}
+
+Make sure you understand if-conditions in Scala: They are
+\emph{expressions}, meaning they need to calculate a result. For
+example an \texttt{if} without an else-branch is nearly always
+\emph{not} what you intend to write (because you are not meant to
+change any ``state'' outside the expression). Also, remember the quirks
+in Scala with if-conditions needing parentheses and there is no
+\texttt{then}-keyword.
+
+\begin{lstlisting}[numbers=none]
+scala> val s1 = "foo"
+scala> val s2 = "bar"
+scala val s3 = "foobar"
+scala> if (s1 == s2) print("equal") else print("unequal")
+scala> if (s1 ++ s2 == s3) print("equal") else print("unequal")
+\end{lstlisting}
+
+\subsection*{Task 4 (Maps)}
+
+Write \texttt{for}-comprehensions that enumerate all triples containing the numbers 1 - 5. That is,
+print the list
+
+\[
+\texttt{(1,1,1)}, \texttt{(2,1,1)}, \texttt{(3,1,1)} \;\ldots\; \texttt{(5,5,5)}
+\]
+
+\noindent
+Modify the \texttt{for}-comprehensions such that only triples are
+printed where the sum is divisible by 3. Then sort the list according
+to the middle element (for this use \texttt{sortBy}).
+
+\subsection*{Task 5 (Pattern-Matching)}
+
+\subsection*{Task 6 (Web-Crawler)}
+
+Write a pretty print function for lists of integers which
+``condenses'' elements in the list, meaning if there is a number
+several times in a row, then print out \mbox{\texttt{n x e}}, where
+\texttt{n} is the number of repetitions and \texttt{e} is the
+number. For example
+
+\begin{lstlisting}[numbers=none]
+ List(1,1,1,2,3,3) => List(3 x 1, 2, 2 x 3)
+ List(1,2,3,4,4,4) => List(1, 2, 3, 3 x 4)
+ List(1,1,1,1,1,1) => List(6 x 1)
+ List(1,1,1,2,1,1) => List(3 x 1, 2, 2 x 1)
+\end{lstlisting}
+
+You might like to define a separate function that first counts the occurences
+for each element and returns a list of (Int, Int)-pairs .
+
+\end{document}
+
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: t
+%%% End: