http://ayende.comAyende @ RahienCopyright (C) Ayende Rahien 2004 - 2021 (c) 202660It is a matter of who your users are. I am generally nervous about giving a user that much power, it require a lot of fore-planning Error messages, for instance, can completely throw a user off. Then you come and put a comma in and it works. I believe that they should be able to read it, writing it is nice, but optional. http://ayende.com/3040/building-an-external-dsl#comment8http://ayende.com/3040/building-an-external-dsl#comment8Wed, 12 Dec 2007 22:48:40 GMTOren, My team has one question about this: how would you go about putting this in the hands of business users to define business rules? Or would you? I have my own opinion on this matter, but I'm curious to see what you think. http://ayende.com/3040/building-an-external-dsl#comment7http://ayende.com/3040/building-an-external-dsl#comment7Wed, 12 Dec 2007 22:40:08 GMTSwitching to the ludic matter you can take a look at Inform 7 (http://www.inform-fiction.org/I7/Welcome.html), an interactive fiction natural English-language. http://ayende.com/3040/building-an-external-dsl#comment6http://ayende.com/3040/building-an-external-dsl#comment6Wed, 12 Dec 2007 08:21:28 GMTYou might want to have a look at Eclipse openArchitectureWare (http://www.eclipse.org/gmt/oaw/) and its accompanying xText framework (http://www.eclipse.org/gmt/oaw/doc/4.2/html/contents/xtext_reference.html), It's much further advanced than anything similar you will find in the .NET space (even the DSL tools) - and available free of charge. We've been successfully using it on a couple of project so far, both with and without an associated source code generation process (using oAW xPand). http://ayende.com/3040/building-an-external-dsl#comment5http://ayende.com/3040/building-an-external-dsl#comment5Wed, 12 Dec 2007 07:57:43 GMTArnon, Yes, I saw that. This is really nice if you want to do known value replacements, not really good for a language invocation http://ayende.com/3040/building-an-external-dsl#comment4http://ayende.com/3040/building-an-external-dsl#comment4Wed, 12 Dec 2007 07:45:07 GMTTake a look at the link for how you can do something close to plain English parsing in Ruby: http://blog.davidchelimsky.net/articles/2007/10/21/story-runner-in-plain-english Arnon http://ayende.com/3040/building-an-external-dsl#comment3http://ayende.com/3040/building-an-external-dsl#comment3Wed, 12 Dec 2007 07:42:33 GMTI just read through the code on this (which I hadn't fully before). This is an elegant solution. I like the way you used refleciton to translate the textual expressions into actual invocations on your domain model. I am surprised if you went that far that you didn't just emit the acutal IL. :) http://ayende.com/3040/building-an-external-dsl#comment2http://ayende.com/3040/building-an-external-dsl#comment2Wed, 12 Dec 2007 07:36:28 GMTFreaking spooky Oren. I built a prototype at work for an external DLS that would allow business users to configure business rules through a GUI that looks like Outlook E-mail Rules (Don't get me started on the "why" of this - I have no influence on whether or not such a thing should be done, only I must display how it can be done). My internal code looks frighteningly similar to yours, especially the Execute() method, where first you're looping through conditions, and then actions. Neat stuff. http://ayende.com/3040/building-an-external-dsl#comment1http://ayende.com/3040/building-an-external-dsl#comment1Tue, 11 Dec 2007 23:39:34 GMT