Xtext is an open-source and popular framework for the development of domain-specific languages. The contract is appealing: specify a grammar and you get for free (no effort) a parser (ANTLR), a metamodel, a comprehensive editor (working in Eclipse, or even in the Web), and lots of facilities for writing a compiler/an interpreter.

For instance, you can write a compiler (in Java or Xtend) that generates on-the-fly when a user edits his or her programs (with the generated editor of course). Sometimes, there is the need to have a standalone solution because you want to develop outside Eclipse or simply because you want to integrate your compiler as part of a bigger thing (e.g., a Web application).

ParserHelper is nice for unit testing your compiler (see this tutorial). However ParserHelper depends on @RunWith(XtextRunner). So outside @Test methods, you cannot use it since dependency injection does not apply.

A possible workaround is to edit .mwe2 file and generate a “Main” class:

language = StandardLanguage {
            name = "org.xtext.example.mydsl.Mml"
            fileExtensions = "mml"
...            
            generator = {
                generateJavaMain = true 
            }            
            
        } 

It injects for you the good dependencies and so you have an executable, standalone Java program.

Another solution is to use an helper function that loads the model out of a string content: see this gist

The principle is to write the string into a temporary file and parses this file (URI) to obtain a model. Then you can traverse your model and compile it. I provide similar facilities as part of an MDE/DSL/SPL course at University of Rennes 1

I thank Manuel Leduc for his nice advices about DSL and Xtext.