An infrastructure is provided for creating applications for mobile information devices, using a tag-based markup language. Developers can use the markup language to define applications and content based on easily manipulated textual tags, rather than having to write specific source code. A compiler, processes the tags in several phases. In one phase, a hierarchical object model of the application is populated with objects. Then, in another phase, a generator traverses the object model hierarchy in a top-down manner, producing source code files corresponding to objects in the object model. The code files may include various elements, for example screens, forms, and servlets. For each element required to be generated, an appropriately configured generator class is invoked. The output code can be Java source code.