More SyntaxSort description (#48)

Add descriptions to some of the `SyntaxSort` tags.  More to come.

ltx/file.tex

@@ -107,7 +107,7 @@ \section{Basic data types}
 \begin{itemize}
 	\item \type{u8}: $1$ octet, with alignment $1$; usually equivalent to C++'s \code{uint8_t}
 	\item \type{u16}: $2$ octets, with alignment $2$; usually equivalent to C++'s \code{uint16_t}
-	\item \type{u32}: $4$ octets, with alignment %4%; usually equivalent to C++'s \code{uint32_t} 
+	\item \type{u32}: $4$ octets, with alignment $4$; usually equivalent to C++'s \code{uint32_t} 
 \end{itemize} 
 
 \subsection{File offset in bytes}
@@ -152,6 +152,13 @@ \subsection{Sequence}
 The \field{start} field is an index into the partition the sequence is part of.  It designates the first item in the sequence.
 The \field{cardinality} designates the number of items in the sequence.
 
+\subsection{Arrays}
+\label{sec:ifc-array-type}
+Occasionally, a contiguous sequence of $n$ items of type $T$ may be represented inline as having type \arrayType{n}{$T$}.
+Such a group of items is called an array of $n$ elements.  Each item in that array is referred to via indices 
+$0$ through $n-1$ inclusive.
+The inline representation means that the $n$ items are represented consecutively in the containing structure.
+
 \subsection{Content Hash}
 \label{sec:content-sha256-hash}
 The interesting portion of the content of an IFC file is hashed using SHA-256 algorithm, and stored as a value of type \type{SHA256}:

ltx/ifc-format.sty

@@ -45,6 +45,7 @@
 \newcommand{\clipType}[2]{\clipValue{\type{#1}}{#2}}
 \newcommand{\field}[1]{\textit{#1}}
 \newcommand{\type}[1]{\textsl{#1}}
+\newcommand{\arrayType}[2]{\ensuremath{#1\times\type{#2}}}
 
 \newcommand{\hexvalue}[1]{\textsf{0x\nhex{2}{#1}}}