Function transformXmlExpr

src/backend/parser/parse_expr.c:2393–2520

}

static Node *
transformXmlExpr(ParseState *pstate, XmlExpr *x)
{
	XmlExpr    *newx;
	ListCell   *lc;
	int			i;

	newx = makeNode(XmlExpr);
	newx->op = x->op;
	if (x->name)
		newx->name = map_sql_identifier_to_xml_name(x->name, false, false);
	else
		newx->name = NULL;
	newx->xmloption = x->xmloption;
	newx->type = XMLOID;		/* this just marks the node as transformed */
	newx->typmod = -1;
	newx->location = x->location;

	/*
	 * gram.y built the named args as a list of ResTarget.  Transform each,
	 * and break the names out as a separate list.
	 */
	newx->named_args = NIL;
	newx->arg_names = NIL;

	foreach(lc, x->named_args)
	{
		ResTarget  *r = lfirst_node(ResTarget, lc);
		Node	   *expr;
		char	   *argname;

		expr = transformExprRecurse(pstate, r->val);

		if (r->name)
			argname = map_sql_identifier_to_xml_name(r->name, false, false);
		else if (IsA(r->val, ColumnRef))
			argname = map_sql_identifier_to_xml_name(FigureColname(r->val),
													 true, false);
		else
		{
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 x->op == IS_XMLELEMENT
					 ? errmsg("unnamed XML attribute value must be a column reference")
					 : errmsg("unnamed XML element value must be a column reference"),
					 parser_errposition(pstate, r->location)));
			argname = NULL;		/* keep compiler quiet */
		}

		/* reject duplicate argnames in XMLELEMENT only */
		if (x->op == IS_XMLELEMENT)
		{
			ListCell   *lc2;

			foreach(lc2, newx->arg_names)
			{
				if (strcmp(argname, strVal(lfirst(lc2))) == 0)
					ereport(ERROR,