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The Scala and FPL friendly event in Paris!

October 24th and 25th, 2013. Paris, France

Our journey from UML/MDD to Scala macros

Ebiznext, the company I work for has built custom software for the past ten years through the use of UML/MDA techniques to produce code faster, guarantee the code quality and maintain synchronization between the documentation and the code. Until recently, we applied the same technique and used to same tools to generate code for the Typesafe stack. With the advent of macros in scala, the process is being reversed. Instead of a top down approach going from the model to the code, we will go the other way around.

Throughout this session I will describe how we make use of Scala macros in order to produce the database access layer code.

The Macros library

The first part describe (1) the set of macros that are in charge of generating all the boilerplate code Slick needs to describe the database schema and (2) the set of macros that we defined to implement dynamic finders (à la grails) to supplementthe Slick DSL.

Generating Slick boilerplate code with macros annotations

This part describes how we generate abstract syntax trees and how symbols, trees and types correlate to the source code through the implementation of the @Entity and @Transactional macro annotations. The @Entity macro annotation when applied to a case class generates all the boilerplate code Slick requires to describe a table including foreign keys for members who reference another case class The @Transactional annotation when applied to the method definition, generates the required enclosing block required to execute the slick code inside a thread local session

Using Def macros to create dynamic finders.

We initially used the Scala Dynamic marker trait to generate dynamic finders. We shifted to Def macros for obvious reasons. This part dives into the new Scala 2.10 reflection API and how we use it to create dynamic finders and CRUD methods.

More info

Event type: Long session (42 minutes)

Language:

Location: Room 2

Date / Time: Thursday 17:15 - 18:15

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Speakers

Hayssam Saleh

Track