Why "Polyglot Programming" or "Do It Yourself Programming Languages" or "Language Oriented Programming" sucks?

Last year we saw the launch of a new Web programming language Dart - Structured Web Programming from Google. A very interesting approach to support web application development. Not so long after Go, Groovy, Ruby, Scala, << name your DSL here >>; we see Dart. Is it a good thing to have at least one programming language to solve one problem? The answer is, like we already know, it depends.

Some important backgrounds you should know about the multi programming language paradigm are following:

1. You can read Martin Fowler article about language oriented programming with language workbenches which enables you to write small programming languages easily. In this article I see everyone writing their small languages, everywhere. In this concept we see DSL (Domain Specific Language) as the future of our programming activities. Source: http://martinfowler.com/articles/languageWorkbench.html

2. Neal Ford talked about Polyglot Programming, combining multiple programming languages in application development. Later Mr. Fowler add this paradigm with Polyglot Persistence, using different type of databases within one application. Source: http://memeagora.blogspot.com/2006/12/polyglot-programming.html and http://martinfowler.com/bliki/PolyglotPersistence.html

Since 2006 I already discussed and collected some experiences in multi programming language paradigm:

1. I remember a “hot” discussion in year 2006 with Sebastian Meyen, chief in editor of JavaMagazin Germany, also the biggest organisator of Java Conference JAX. We agreed to see the future of programming in multi language paradigm concept. I also said that all those languages will be based on Java VM. I also told him that in one day SAP will move ABAP as a language which can be run within the Java VM, so just another language within the Java environment, no two different personalities any more. Today we see the beginning of this in the project called Caffeine ABAP. Source: https://cw.sdn.sap.com/cw/groups/caffeine

2. Also in year 2006 I had a project in which we also used different kind of languages and also creating our own DSL:

• Java for the most implementation stuffs
• UML for design of the business objects. We generate a lot of things using the concept of MDA (Model Driven Architecture)
• Groovy for a lot of things, especially for writing unit tests
• Based on ANTLR we create our own DSL for some aspects of the application

It was really exciting and we had some very good programmers in the project. The result was a very nice and flexible product, just as what we expected in the beginning of the project. Please read this article in German language for more information: http://www.sigs.de/publications/os/2009/02/dewanto_egger_OS_02_09.pdf

So after all those nice things about multi language paradigm I told you, why this sucks at the end? Here are some reasons from my point of view:

1. As typical in application development the problem comes first in the maintenance phase, after all the capable programmers leave the project. Did you, programming language creators ever try to teach a new programming language to a “normal”, 9 till 5 programmers? I’m not talking about 9 (am) till 9 (pm) programmers who love to learn every new languages. It is definitely tough to be proficient in one programming language. This is comparable with the languages we speak everyday. I’m not a native English speaker, so I’m quite sure that I made a lot of syntax and grammar errors in this article. It is possible to be able to speak three or four languages perfectly but this is an exception.

2. Did you ever try to maintain a big Struts web application with AJAX? Just try to add a functionality and you will end up with creating and editing a lot of files: Action and Form files, Struts XML configuration files, JavaScript files with JSON and also HTML or JSP files. Can you imagine to add Groovy, Scala, Dart additionally into that web app? The complexity of such a project is very high.

3. Creating a new programming language means that you also have to build the environment for it. Good IDE, good documentation, good community support, clear roadmap, backward compatibility are some points to be done. Groovy is a bad example of this. In the early version of this language the editor for Eclipse was really bad. After a while they improved the editor but they make a lot of basic changes in the language so your old groovy applications do not work anymore. You are punished to update to the new version. This never happens to Java. You still can compile Java 1.1 applications with Java 6 compiler.

4. Before you are creating your own DSL with e.g. ANTLR ask those language Gurus first, how hard it is to maintain a programming language for a long term. Before you discuss with them don’t ever create your own DSL. Especially if you are working for SME (Small and Medium sized Enterprise). With a small team and small budget you will never ever maintain your own language decently.

So in year 2012, six years after my support to Polyglot Programming, I hope to see following things happen:

1. One language for all aspects in one application is the best concept ever. I name this as “One for All Programming Language paradigm”. Just like we don’t use English for technical language, German as literate language and Indonesian as community language, to be able to communicate internationally with each other we just use English pragmatically for all aspects of our life. In Germany you need to speak German in all aspects to be able to communicate with others. My best solution sofar is Java + XML, that’s it, no more, no less. No mixing with Groovy, Dart, Ruby, Scala, << name your DSL here >> in one application. Especially if you are working as contractor, please don’t try to use all those languages just for a small Java web application. I don’t say that you should not use the other languages at all. The only thing which is important is not to mix those languages in one application. In SME you maybe also want to use just one programming language for all your applications.

2. Concept like GWT (Java to JavaScript compiler) or XMLC (XML compiler which compiles XML, HTML to Java classes) is great. You can work just in plain Java. Guice with all Java and no XML is also a great solution (I know that SpringFramework is also doing this with Annotations). Android is great because it uses Java as its application programming language.

As a conclusion I can only hope to see more such pure and plain Java solutions in year 2012!