An implementation of the JsonPath spec for Clojure.
It doesn't provide a full implementation. The following syntactic elements are supported.
$: Select the root of the object..: Descend to a single child...: Recursive descent to select all children.*and<name>: Select the child objects matching a name, or all immediate children when using*. Unlike in JavaScript, thenamecan contain hyphens (-). This is convenient as Clojure data structures often use hyphens in keys.[<number>]and[*]: Select either a specific element of an array, or all elements of an array.[?(<expr>)]: Filter to select objects that match an expression. Supports all equality operators (=,!=,<,<=,>,>=) and can use@to refer to objects from the current object.
See test/json_path/test/json_path_test.clj for more examples.
For a comparison to other implementations see the json-path-comparison project.
Notable features missing from the JsonPath spec are multiple array
indices ([,]),array slicing ([start:end:step]) and arbitrary
script expressions ([(...)]). Also, the set of expression operators
should probably be expanded.
json-path will never support the arbitrary script expressions
feature. That's just a plain bad idea.
JsonPath is missing a parent operator. This is necessary for
performing cousin operations. I propose using ^ as the parent
operator. It would be used anywhere that the . child operator could
be used.
The supported expression operators should be expanded. And as arbitrary script expressions won't be supported, functions for operations like length should be added.
Accepts standard Clojure data structures: maps and sequences. Assumes that maps contains keywords for the child objects.
(require 'json-path)
(json-path/at-path "$.foo" {:foo {:bar "Hello, world!"}})
; => {:bar "Hello, world!"}
(->> (json-path/query "$..bar" {:foo {:bar "Hello"}})
(map :path))
; => ([:foo :bar])Copyright (C) 2011 Giles Alexander
Distributed under the MIT License.