procedures.tex

%!TEX root = reference.tex
\chapter{Action Procedures}
\label{procedures}

An action procedure is an action script -- a program for performing actions. Analogously to functions and other rule types, procedures are written as a set of action rules.

\begin{figure}[htbp]
   \includegraphics[width=0.9\textwidth]{diagrams/procedureFig}
   \caption{Action Procedure}
   \label{procedureFig}
\end{figure}

\section{Action Procedures and Type Safety}

A procedure is type safe if the action(s) in the body are type safe -- in the environment augmented by the variables in the head of the procedure.

\begin{prooftree}
\AxiomC{\typeprd{E}{name}{\q{action [}T\sub1,\ldots,T\subn\q{]}}}
\AxiomC{\typesafe{E\minsert{\cup}H\sub1:T\sub1\minsert{\cup}\ldots\minsert{\cup}H\subn:T\subn}{A}}
\BinaryInfC{\typesafe{E}{name\q{(}H\sub1,\ldots,H\subn\q{) begin }A\q{ end}}}
\end{prooftree}