MetaEd IDE - Core Concepts

This section outlines core concepts related to MetaEd.

Before You Begin

The MetaEd IDE provides implementers with a quick and painless means of extending various Ed-Fi technology components. All extensions to Ed-Fi technical products must adhere to the Ed-Fi Extension Framework. The MetaEd IDE generates extended technical artifacts aligned with the guidance and principles in the Extension Framework.  

If you don't have an Ed-Fi ODS / API, or you don't use the Ed-Fi Data Standard, then the MetaEd IDE can be a pleasant diversion from the workaday world, but won't really do anything for you.

However, if you are looking to implement and extend Ed-Fi technology, then the MetaEd IDE is for you.

What Is MetaEd? And What Is the MetaEd IDE?

The term MetaEd is a general term encompassing a few related things.

MetaEd Language

The MetaEd Language is a lightweight domain-specific language that describes Ed-Fi data elements, their properties, and their organization into entities. The language is meant to be easily readable by developers and business analysts. Here's an example snippet for the first name of a student:

Shared String FirstName [49]
	documentation "A name given to an individual at birth, baptism, or during another naming ceremony, or through legal change."
	min length 1
	max length 75

If you look at the Ed-Fi technical artifacts, you'll find that Student.Name.FirstName in the Ed-Fi Core XSD is a string with a minLength of 1 and maxLength of 75 characters. Similarly, the Student.FirstName field in the ODS / API database is an NVARCHAR with a length of 75. The simple statement above in the MetaEd Language is what drives those definitions in the Ed-Fi technical artifacts.

MetaEd language files must always have a .metaed extension.

MetaEd Generator

The MetaEd Generator is a command-line software component that compiles MetaEd language files into technical artifacts. Since the MetaEd Generator is an executable, it can be run independently from the MetaEd IDE. For example, some advanced users may find it useful to invoke the Generator in a continuous integration environment. Most users, however, will simply work with the Generator through the IDE.

MetaEd IDE

The MetaEd IDE provides an integrated development environment experience for the Language and the Generator.

What Does MetaEd Output?

The MetaEd IDE outputs several technical and documentation artifacts, including:

• SQL scripts to extend an Ed-Fi ODS / API
• XSD schema definitions to extend the Ed-Fi Data Standard
• Excel data dictionaries for XSD and SQL that combine both core and extended definitions

How Does MetaEd Work?

It's not necessary to understand the MetaEd architecture in order to use the system, but it may be of interest to advanced users.

The User Interface (UI) is a Visual Studio Code Extension. The MetaEd IDE is a plug-in to the open-source Visual Studio Code (VS Code) text editor. The IDE uses VS Code to handle traditional user-facing features such as syntax highlighting and semantic validation for source files. It also provides a structured wrapper for the setting of configuration values, invoking the build system, and so forth.

Compiling is in Code. MetaEd leverages a command-line application that "compiles" the source MetaEd language files into Ed-Fi-aligned artifacts. The application contains the parsing/lexing code that reads the source files, the code that turns your source into an abstract model, and the generator code that turns the abstract model into concrete artifacts. If you have the IDE, you also have a copy of the command-line application on your local machine. As the name implies, the command-line application can be used independent of the MetaEd IDE via the command line — but this documentation focuses on the IDE because that's how most users will interact with the language.

The MetaEd Language is Customized for Ed-Fi Technology. The heart of MetaEd is the MetaEd language, which is a domain-specific language written for the Ed-Fi Alliance. The language works because it contains all the core concepts around modeling and data typing that are relevant to Ed-Fi technology — and the language interpreters and generators know how to turn those concepts into concrete technology artifacts. The language was written using the popular ANTLR framework.

That Sounds Awesome. Does MetaEd Do Everything Needed to Extend an Ed-Fi Implementation?

In a word, no. Depending on your development process and your implementation environment, you may have additional work to do — and, of course, you'll need to validate and test any code thoroughly. But, with that disclaimer aside, field testing has shown that the MetaEd IDE can drastically reduce both the initial development and the revision cycle time on extension projects.