concept-design

Building Applications with Concept Design

This repository is an application meant to be built according to the principles of concept design, a new approach to modularity first introduced in Daniel Jackson's "The Essence of Software". This approach describes a way to build software in terms of concepts, which describe behavior that captures a familiar unit of functionality with a single purpose. These are then composed together using synchronizations, which are declarative statements that describe how actions of different concepts are composed.

Concepts

A concept is a highly-reusable and standalone service designed to fulfill a single purpose. Unlike microservices or traditional OOP classes, concepts must remain independent from one another and cannot import or reference other concepts. They can be specified using a simple specification language and stored as .concept files, such as:

<concept_spec>

concept User

purpose 
    to associate identifying information with individuals

state
    a set of Users with
        a name String
        an email String

actions
    register (user: Users, name: String, email: String) : (user: Users)
        associate user with users
        associate name and email if both unique and valid
        return the user reference
    register (user: Users, name: String, email: String) : (error: String)
        if either name or email is invalid or not unique, describe error
        return the error description

    update (user: Users, name: String) : (user: Users)
        if name is unique, update user's name
        return the user reference
    update (user: Users, name: String) : (error: String)
        if name is not-unique, describe error
        return the error description

    update (user: Users, email: String) : (user: Users)
        if email is unique and valid, update id's email
        return the user reference
    update (user: Users, email: String) : (error: String)
        if email is not-unique or invalid, describe error
        return the error description

operational principle
    after register () : (user: x) and update (name: "xavier") : (user: x)
    for any user u such that u's name is "xavier", u must be x

</concept_spec>