% vim: set spelllang=nl: \subsection{\texttt{Cat}} \label{sec:rules:cat} \begin{quote} + - concatenates the top two strings on the stack. The string pushed earlier appears earlier in the resulting string, eg \smurfinline{"Zork" "mid" +} would result in the string \texttt{Zorkmid} being placed on the stack. \end{quote} De string bovenop de stack wordt toegevoegd aan de string hieronder. Het resultaat wordt op de stack gezet. Dit geeft de volgende regel: $$ \begin{prooftree} \trans {\pgm}{\ip}{(\push{s1~s2}{\stk''}, \str)} {\ip'}{\op}{\st} \justifies \trans {\StmCat:\pgm}{\ip}{(\stk,\str)} {\ip'}{\op}{\st} \using{\rcatns} \qquad \text{met\enspace \parbox{36mm}{$(s_2,\stk') = \pop{\stk}$,\\$(s_1,\stk'') = \pop{\stk'}$.} } \end{prooftree} $$