::= "." "(" ? ")" | ".sum()" | ".as(" ")" ::= "set" | "define" | "as" | "length" | "reverse" | "split" | "format" | "search" | "concat" | "replace" | "add" | "subtract" | "multiply" | "divide" | "idivide" | "mod" | "round" | "floor" | "ceiling" | "power" | "abs" | "sqrt" | "remove" | "first" | "last" | "find" | "glue" | "contains" | "each" | "sum" | ::= ("," )*