L=list()  /// \sleftarrow{\normalfont an empty list }
L(2) = testmatrix('magi',3) /// \sleftarrow {\begin{minipage}[t]{6cm}{\nf{}list assignment using \verb+L(i)=val+. Note that\\ \verb+L(1)+ does not exist}\end{minipage}}
L(0) = 34; /// \sleftarrow{\normalfont add an element at the begining of list}
L($) = 'X' /// \sleftarrow{\normalfont replace last element}
L($+1) = 'Y' /// \sleftarrow{\normalfont add an element at {end} of list}
[a,b]=L([1,3]) /// \sleftarrow{\normalfont extraction, we can extract several argument in one call}
L(2)=null();  /// \sleftarrow{\normalfont deletion of the second list element}