Describing a language editor can be repetitive, for instance when you have to define expressions. expression '+' expression and expression '*' expression is a typical example. From the grammar file that describes the language structure it's possible to recognize repetitive rule structures and build an editor in a consistent way.

The PE project defines a grammar and generates AST in a way not related to any projectional editor. PE4MPS project imports the generated ASTs into MPS generating for example from this rule:

Graph:
      strict=STRICT? type=GraphType name=string?
      statementList<indentList('{', '}')>=Statement*
    ;
    

this MPS editor:

The idea to sketching UI, or other types of drawing, using text file is not new. Text can be embedded into text files so a whole document can be defined using only text. This is the approach used by Sphinx, with it you can use reStructuredText to define your HTML or PDF documentation.

Sphinx is integrated with PlantUML so you are able also to define UI, UML diagrams, charts using text.

The subproject used by PlantUML to define UI sketch is called Salt. What I do not like about Salt it's that it uses lines, curves and text to draw a UI sketch. This way the result is not realistic.
And ok... I would like to exercise with ANTLR.

If you are a Java developer and you are interested in Domain Specific Language (DSL) and Code Generation, soon or late you are going to play a bit with ANTLR. In addition if you are such kind of person you will probably know the Martin Fowler bliki. Now something personal: I in general dislike working with graphic tools when I can do the same thing by coding and/or command line (who knows if in one of my next posts I will decide to explain why). I also dislike to store into a database things that are much more comfortable into the file system. All these reasons drive me to implement my own bliki.