# gs-predicate

[GS Open Source](https://garrity.co/open-source.html) |
[License (MIT)](./LICENSE)

Serializable predicates for Scala 3. [Circe](https://github.com/circe/circe) is
used for JSON representations.

- [Usage](#usage)
    - [Dependency](#dependency)
    - [JSON Predicates](#json-predicates)
- [List of Predicates](#list-of-predicates)
- [Donate](#donate)

## Usage

### Dependency

This artifact is available in the Garrity Software Maven repository.

```scala
externalResolvers +=
  "Garrity Software Releases" at "https://maven.garrity.co/gs"

val GsPredicate: ModuleID =
  "gs" %% "gs-predicate-api-v0" % "$VERSION"
```

### JSON Predicates

The following example evaluates whether some JSON object:

- Contains an object `foo`...
- That contains an array `bar` such that any one element of `bar`...
- Contains an array `baz` such that all elements of `baz`...
- Are objects that contain some property `xyz` with value `"example"`.

```scala
import io.circe.Json
import gs.predicate.v0.api.*
import gs.predicate.v0.json.*
import gs.predicate.v0.json.query.JsonQuery

val predicate = JsonComparisonPredicate(
    JsonQuery.compile("foo.bar[any].baz[all].xyz"),
    JsonComparison.Eq(Json.fromString("example"))
)

val json = io.circe.parser.parse("""
{
    "foo": {
        "bar": [
            {
                "baz": [
                    { "xyz": "example" },
                    { "xyz": "example" }
                ]
            },
            {
                "baz": [
                    { "xyz": "oops" },
                    { "xyz": "example" }
                ]
            }
        ]
    }
}
""".stripMargin)

assertEquals(predicate.eval(json), Predicate.Result.matched())
```

## List of Predicates

- `true`
- `false`
- `and`
- `or`
- string comparison
- json comparison

### List of Comparison Operations

- `true`
- `false`
- `and`
- `or`
- `eq`
- `neq`

#### For Strings

- `contains`
- `prefix`
- `suffix`

#### When Parsed as Integer

- `<`
- `<=`
- `>`
- `>=`
- Inclusive Range
- Exclusive Range

#### When Parsed as Date

- `before`
- `after`
- Inclusive Range
- Exclusive Range

## Donate

Enjoy this project or want to help me achieve my [goals](https://garrity.co)?
Consider [Donating to Pat on Ko-fi](https://ko-fi.com/gspfm).