function y=f(x) ; a = 2*%pi, y = x+a, endfunction 
f(2); /// \sleftarrow{\normalfont \verb+a+ is not displayed }
function y=g(x) ; a = 2*%pi, print(%io(2),a), y = x+a, endfunction 
g(2);/// \sleftarrow{\normalfont force display of \verb+a+ using \verb+print+}