I would need to build a Tree that would retrieve something like this using Lark package: start expr or_expr and_expr comp_expr identifier Name comparator eq value 'Milk' comp_expr identifier Price comparator lt value 2.55 The grammar used is the following from lark import Lark odata_grammar = """ start: expr expr: or_expr or_expr: and_expr ("or" and_expr)* and_expr: comp_expr ("and" comp_expr)* comp_expr: identifier comparator value -> comp_expr comparator: "eq" | "lt" | "gt" | "le" | "ge" | "ne" value: STRING | NUMBER identifier: CNAME STRING: /'(''|[^'])*'/ DATE: /\d{4}-\d{2}-\d{2}/ NUMBER: /-?\d+(\.\d+)?/ %import common.CNAME %import common.WS %ignore WS """ parser = Lark(odata_grammar, start='start', parser='lalr') url_filter = "Name eq 'Milk' and Price lt 2.55" tree = parser.parse(url_filter) print(tree.pretty()) When I print this tree, I find that the Tree retrieved is the following: start expr or_expr and_expr comp_expr identifier Name comparator value 'Milk' comp_expr identifier Price comparator value 2.55 The comparator for some reason is not retrieved. And I say retrieved because the Lark package seems to detect it but it is not printed in the tree. This is curious because when I try to "force" the comparator to doing something like this in the grammar comparator: "eq" -> eq what I get is the comparator named as eq but not comparator: eq. Continue reading...
