cation). </P>


<PRE>
   CharacterSets = &quot;CHARACTERS&quot; {SetDecl} .
   SetDecl       = SetIdent &quot;=&quot; CharacterSet .
   CharacterSet  = SimpleSet { (&quot;+&quot; | &quot;-&quot;) SimpleSet } .
   SimpleSet     = SetIdent | string | &quot;ANY&quot; | SingleChar [&quot;..&quot; SingleChar ] .
   SingleChar    = &quot;CHR&quot; &quot;(&quot; number | character &quot;)&quot; .
   SetIdent      = ident .
</PRE>

<P>Simple character sets are denoted by one of: </P>
<TABLE>
<TR>
<TD>string
<td> a 