Title: Accord: A sane validation library for Scala

Type: Open Source in Israel

Tags: programming-framework

Abstract:

Status: accepted

Accord is a validation library written in and for Scala. Compared to JSR 303 and Scalaz validation it aims to provide the following:

  • Composable: Because JSR 303 is annotation based, validation rules cannot be composed (annotations cannot receive other annotations as parameters). This is a real problem with some Scala features, for example Options or collections. Accord's validation rules are trivially composable.
  • Simple: Accord provides a dead-simple story for validation rule definition by leveraging macros, as well as the validation call site (see example below).
  • Self-contained: Accord is macro-based but completely self-contained, and consequently only relies on the Scala runtime and reflection libraries.
  • Integrated: Other than providing its own DSL and matcher library, Accord is designed to easily integrate with other libraries, and provides out-of-the-box integration with Spring Validation, Specs2 and ScalaTest.

Accord is developed and used at Wix and distributed under the Apache License, Version 2.0, which basically means you can use and modify it freely. Feedback, bug reports and improvements are welcome!