private FilterOperand GetLhs(FilterParser.Elem_opContext elem_opContext)
{
FilterOperand lhs = Evaluate(elem_opContext.elem_op()?[0]);
if (lhs == null)
{
lhs = Evaluate(elem_opContext.attr_op().First());
}
return(lhs);
}
private FilterOperand GetRhs(FilterParser.Elem_opContext elem_opContext)
{
FilterOperand rhs = Evaluate(elem_opContext.lit_op());
if (rhs == null)
{
rhs = Evaluate(elem_opContext.attr_op().Last());
}
if (rhs == null)
{
var elem = elem_opContext.elem_op();
if (elem?.Length == 2)
{
rhs = Evaluate(elem_opContext.elem_op()?[1]);
}
}
return(rhs);
}
private ElementOperand Evaluate(FilterParser.Elem_opContext elem_opContext)
{
if (elem_opContext.BR_OPEN() != null ||
elem_opContext.BR_CLOSE() != null)
{
elem_opContext = elem_opContext.elem_op()[0];
}
var comparison = elem_opContext.COMPARISON_OPERATOR();
var or = elem_opContext.OR();
var and = elem_opContext.AND();
if (comparison != null || or != null || and != null)
{
// First is elem or attribute[0], second is lit or attribute[1]
var lhs = GetLhs(elem_opContext);
var rhs = GetRhs(elem_opContext);
WhereClause.Push(and != null ? FilterOperator.And : or != null ? FilterOperator.Or :
ToOperator(comparison), lhs, rhs);
return(new ElementOperand {
Index = (uint)WhereClause.Elements.Count - 1
});
}
var inlist = elem_opContext.IN();
if (inlist != null)
{
var lhs = GetLhs(elem_opContext);
var list = Evaluate(elem_opContext.list);
WhereClause.Push(FilterOperator.InList, lhs.YieldReturn().Concat(list).ToArray());
return(new ElementOperand {
Index = (uint)WhereClause.Elements.Count - 1
});
}
throw new Exception();
}
