json-logic-go

This parser accepts JsonLogic rules and executes them in Go.

The JsonLogic format is designed to allow you to share rules (logic) between front-end and back-end code (regardless of language difference), even to store logic along with a record in a database. JsonLogic is documented extensively at JsonLogic.com, including examples of every supported operation and a place to try out rules in your browser.

API

Apply

func Apply(inputs ...string) (interface{}, error)

The first input is the json rule, as a string:

Apply(`{ "==" : [1, 1] } `);

The second input, optional, is the data source:

Apply(`{ "var" : ["a"] }`, `{ a : 1, b: 2 }`);

Apply() uses json.Unmarshal to convert the string inputs to generic interface{}.

The return value is of type interface{} because it can be anything such as a string, boolean, map, array, etc. The function may also return an error.

ApplyJSONInterfaces

func ApplyJSONInterfaces(inputs ...interface{}) (interface{}, error)

This has the same behavior as Apply(), but expects inputs already unmarshalled. This should not be used with your own custom types, but rather ONLY with unmarshalled json.

AddOperation

func AddOperation(name string, implementation Operation) error

This allows you to extend the range of operations provided by jsonlogic.
An Operation has should have the following signature: func(args ...interface{}) (interface{}, error)

For example:

func add(args ...interface{}) (interface{}, error) {
	x, y := float64(args[0].(float64)), float64(args[1].(float64))

	return (x + y), nil
}

jsonlogic.AddOperation("add", add)
result, _ = Apply(`{"add": [1, 2]}`)