/// <summary>
/// PRIM
/// </summary>
/// <param name="ts"></param>
/// <returns></returns>
IBoolExpr Prim(TokenStream ts)
{
switch (ts.Current.kind)
{
case Kind.VAR:
string varName = ts.Current.nString.ToString();
ts.MoveNext();
return(BoolExpr.CreateVariable(varName));
case Kind.POS: ts.MoveNext(); return(BoolExpr.CreateTrueVariable());
case Kind.NEG: ts.MoveNext(); return(BoolExpr.CreateFalseVariable());
case Kind.LPAR: ts.MoveNext();
IBoolExpr ev = Exists(ts);
if (ts.Current.kind != Kind.RPAR)
{
throw new ApplicationException("Expected Kind.RPAR");
}
ts.MoveNext(); return(ev);
case Kind.RPAR: ts.MoveNext(); return(null);
}
return(null);
}