JMESPath queries over JSON data: the engine behind the MCP catalog's jmespath function.

It implements the specification — field and index access, slices, list, object, flatten and filter projections, multi-select lists and hashes, pipes, ||, &&, !, comparisons, literals, raw strings, expression references and every built-in function — and agrees with the JMESPath compliance suite.

iex> A2UICore.JMESPath.search("people[?age > `30`].name", %{
...>   "people" => [%{"name" => "Ada", "age" => 36}, %{"name" => "Alan", "age" => 29}]
...> })
{:ok, ["Ada"]}
iex> A2UICore.JMESPath.search("sort_by(items, &price)[0].id", %{
...>   "items" => [%{"id" => "b", "price" => 3}, %{"id" => "a", "price" => 1}]
...> })
{:ok, "a"}

A malformed expression, a function called with the wrong number or types of arguments, and an unknown function are errors with category :expression and the codes JMESPATH_SYNTAX, JMESPATH_INVALID_ARITY, JMESPATH_INVALID_TYPE, JMESPATH_INVALID_VALUE and JMESPATH_UNKNOWN_FUNCTION.

iex> {:error, error} = A2UICore.JMESPath.search("foo[", %{})
iex> error.code
"JMESPATH_SYNTAX"

JSON objects are Elixir maps, so keys/1 and values/1 return their entries in map order; the specification leaves that order open.