diff -r ff6787d730d5 -r 260090b54ef9 doc-src/Exercises/2001/a3/generated/Trie2.tex --- a/doc-src/Exercises/2001/a3/generated/Trie2.tex Fri Apr 29 18:13:28 2005 +0200 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,32 +0,0 @@ -% -\begin{isabellebody}% -\def\isabellecontext{Trie{\isadigit{2}}}% -\isamarkupfalse% -% -\begin{isamarkuptext}% -Die above definition of \isa{update} has the disadvantage -that it often creates junk: each association list it passes through is -extended at the left end with a new (letter,value) pair without -removing any old association of that letter which may already be -present. Logically, such cleaning up is unnecessary because \isa{assoc} always searches the list from the left. However, it constitutes -a space leak: the old associations cannot be garbage collected because -physically they are still reachable. This problem can be solved by -means of a function% -\end{isamarkuptext}% -\isamarkuptrue% -\isacommand{consts}\ overwrite\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequote}{\isacharprime}a\ {\isasymRightarrow}\ {\isacharprime}b\ {\isasymRightarrow}\ {\isacharparenleft}{\isacharprime}a\ {\isacharasterisk}\ {\isacharprime}b{\isacharparenright}\ list\ {\isasymRightarrow}\ {\isacharparenleft}{\isacharprime}a\ {\isacharasterisk}\ {\isacharprime}b{\isacharparenright}\ list{\isachardoublequote}\isamarkupfalse% -% -\begin{isamarkuptext}% -that does not just add new pairs at the front but replaces old -associations by new pairs if possible. - -Define \isa{overwrite}, modify \isa{modify} to employ \isa{overwrite}, and show the same relationship between \isa{modify} and -\isa{lookup} as before.% -\end{isamarkuptext}% -\isamarkuptrue% -\isamarkupfalse% -\end{isabellebody}% -%%% Local Variables: -%%% mode: latex -%%% TeX-master: "root" -%%% End: