  When a <B>default</B> branch is taken, the variable will have the
empty list written to it.  This option may be specified at the same
time as the <B>-matchvar</B> option.
<P><DT><A NAME="M11"><B>--</B></A><DD>
Marks the end of options.  The argument following this one will
be treated as <I>string</I> even if it starts with a <B>-</B>.
This is not required when the matching patterns and bodies are grouped
together in a single argument.
<P></DL>
<P>
Two syntaxes are provided for the <I>pattern</I> and <I>bo