gideondk / metaphor

JSON generation and extraction library for Shapeless Records

Metaphor

Metaphor is a small library which leverages the parsing and generating capabilities of spray-json into a solution for the generation and extraction of Shapeless Records:

Shapeless provides an implementation of extensible records modelled as HLists of values tagged with the singleton types of their keys. This means that there is no concrete representation needed at all for the keys. Amongst other things this will allow subsequent work on Generic to map case classes directly to records with their member names encoded in their element types.

Usage

Usage of Metaphor is very straight forward. Generation is done by using the generate function, supplying the record and the appropriate fields to be serialised:

val person =
	("name" ->> "Barraco Barner") ::
	("occupation" ->> "President") ::
	("country" ->> "UK") ::
	("family" ->> List("Michello Barner, Miley Barner", "Sushi Barner")) ::
	HNil

val json = Metaphor.generate(person, "name", "occupation", "country", "family")

Depending on supplied record, the compiler will automagically detect if the fields are available in the record or not.

Extraction is done in a similar manner:

val js = """{"title": "Types and Programming Languages", "id": 262162091, "price": 44.11}""".asJson
val book = Metaphor.extract[String, Long, Float](js, "title", "id", "price")
book("title") == "Types and Programming Languages"

Extracting the appropriate types from the supplied JSON and generating a record with the same supplied field names.

Installation

Start by adding the repo:

"gideondk-repo" at "https://raw.github.com/gideondk/gideondk-mvn-repo/master"

to your SBT configuration and adding the package to your library dependencies:

libraryDependencies ++= Seq(
	"nl.gideondk" %% "metaphor" % "0.1.0"
)

License

Copyright © 2014 Gideon de Kok

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.