diff --git a/VCFv4.3.tex b/VCFv4.3.tex index 9c2bf8542..e40e9a064 100644 --- a/VCFv4.3.tex +++ b/VCFv4.3.tex @@ -151,7 +151,10 @@ \subsubsection{Information field format} \item . (dot): The number of possible values varies, is unknown or unbounded. \end{itemize} -The `Flag' type indicates that the INFO field does not contain a Value entry, and hence the Number must be $0$ in this case. +The `Flag' type can indicate a single boolean value, or an array of boolean values. +To indicate one boolean value it can be defined with Number=$0$ and in this case the presence of the field tag indicates a "true" value, and its absence indicates a "false" value. +Alternatively, Number can take on other values (including 1) as described above. In that case the value of 1 will indicate "true" and 0 will indicate "false". + The Description value must be surrounded by double-quotes. Double-quote character must be escaped with backslash $\backslash$ and backslash as $\backslash\backslash$. Source and Version values likewise must be surrounded by double-quotes and specify the annotation source (case-insensitive, e.g.\ \verb|"dbsnp"|) and exact version (e.g.\ \verb|"138"|), respectively for computational use.