Introduction.pier

!!Introduction

Writing user interfaces is notoriously a tedious task.
It often requires time and a clear understanding of the separation of concerns between the logic of the model and the logic of the user interface.
Indeed, many frameworks mix domain models with widget models.

''Spec'' is a framework for describing user interfaces. 
It allows for the separation of concerns between the different parts of the user interface as expressed in the MVP pattern, on which it is inspired.
''Spec'' emphasizes the reuse of widgets as well as their customization.
The goal of this text is to provide an overview of the functionalities of ''Spec''. 

To avoid possible misunderstandings due to confusion in terminology, we first define the following four terms, which will be used frequently:

;UI Element
:an interactive graphical element displayed as part of the Graphical User Interface.
;UI Model
:an object that contains the state and behavior of one or several UI elements.
;Widget
:the union of a UI Element and its UI model.
;Basic widgets
:low level widgets like a list, a button, etc. They are not composed of other widgets.

The structure of this text is as follows:
First we give a short tutorial on how to define and reuse UIs with ''Spec''.
Then the three axes that form the heart of ''Spec'' are explained. 
In section four the API of the ''Spec'' basic models is detailled as well as how to understand the meta information attached to this API. 
The next section presents the support for dynamic UIs in ''Spec''. 
The sixth section is dedicated to the creation of new ''Spec'' basic widgets, and in section seven the core interpreter loop of ''Spec'' is outlined.

(This documentation was written by Benjamin Van Ryseghem and Johan Fabry, with the suprising help of Sean P. DeNigris.
For corrections, comments and questions about this text please use *Github>https://github.com/SpecForPharo/documentation*.)