The ${\tenbxsl APL\/}$ Publishing System

The APL publishing system consists of two parts, the APL front end and the L^ATEX document style option apl.sty which communicate via a carefully designed interface of TEX macros (see Figure $[*]$ ). This ensures that both parts of the system can be modified independently.

**Figure:** Modules of the Publishing System
$\begin{figure}\centering {\setlength{\unitlength}{1mm} \begin{picture}(78, 50... ...r(0,-1){10}} \put(41,44){\protect{\it APL\/}\ code} \end{picture}}\end{figure}$

Each of these modules is composed of two layers (see Table $[*]$ ). The main task of the low level formatting layer is the printing of single APL symbols. The APL front end maps each symbol into a TEX macro name and produces files to be \input into L^ATEX documents. The L^ATEX style option apl.sty contains one macro definition for each APL character.

APL code is more than just a stream of APL symbols. The high level formatting layer knows about functions, operators, arrays, and expressions. Our APL front end provides special functions for typesetting these objects. The L^ATEX style option defines the corresponding environments.

Table: Layers of the Publishing System

	APL	L^ATEX document
	front end	style option
Low	symbol	symbol
level	translation	construction
formatting
High	APL	logical
level	language	document
formatting	elements	elements

The Publishing System

The ${\tenbxsl APL\/}$ Publishing System