Crate json_predicate

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§Introduction

This specification defines JSON Predicates, a JSON-based RFC4627 syntax for the description and serialization of logical boolean predicate operations intended to be used in conjunction with other JSON-based mechanisms, such as JSON Patch RFC6902, as a means of incorporating conditional processing.

JSON Predicates can be used, for instance, to extend a JSON Patch RFC6902 document to provide for a broader range of conditional processing options not currently supported by JSON Patch.

§Example

Given this JSON:

{
    "a": {
        "b": {
            "c": "ABC!XYZ"
        }
    }
}

We could have a predicate like this:

{
    "op": "and",
    "path": "/a/b/c",
    "apply": [
        {
            "op": "type",
            "value": "string"
        },
        {
            "op": "contains",
            "value": "ABC"
        }
    ]
}

which would evaluate as true if evaluated against the previous JSON.

§Rust Example

let predicate = Predicate::deserialize(serde_json::json!({
    "op": "and",
    "path": "/objA",
    "apply": [
      {
        "op": "defined",
        "path": "/stringX"
      },
      {
        "op": "defined",
        "path": "/stringXYZ"
      }
    ],
}))?;

let evaluted_predicate: bool = predicate
    .test(&ENTRY, PredicateContext::default());

§JSON Patch

The JSON Patch methods described in draft-snell-json-test-07 are not implemented yet.

§Features

§First order predicate

  • “contains”
  • “contains-”
  • “defined”
  • “undefined”
  • “starts”
  • “starts-”
  • “ends”
  • “ends-”
  • “type”
  • “in”
  • “in-”
  • “matches”
  • “matches-”
  • “test”
  • “test-”
  • “less”
  • “more”

§Second order predicate

  • “and”
  • “not”
  • “or”

§References

§License

Licensed under either of

  • Apache License, Version 2.0, (LICENSE-APACHE or LICENSE-2.0)
  • MIT license (LICENSE-MIT or MIT) at your option.

Modules§

builder
context
json_path

Enums§

FirstOrder
Predicate
A Predicate is an Object whose members describe a testable condition that evaluates as either true or false.
SecondOrder

Traits§

PredicateImpl