Typesetting {\tenbxsl APL\/} Expressions

Finally, our system enables the user to typeset APL expressions. The expression


\begin{APLbold}\begin{APLexpr} \APLX\APLleftarrow\APLtwo\APLspace\APLtwo\APLrho ... ...\APLB \APLquote\APLspace\APLquote\APLbr\APLC\APLquote \end{APLexpr}\end{APLbold}

which happens to be the one used to generate the matrix $\APLX$ (our example for formatting arrays) is printed by: 

% EXPR
\begin{APLbold}\begin{APLexpr}
\APLX\APLleftarrow\APLtwo\APLspace
\APLtwo\APLrho
\APLleftparen\APLtwo\APLspace\APLtwo
  ...
\end{APLexpr}\end{APLbold}

The environment APLexpr provides the traditional six space indentation for user input.