DesignAndCode - Architecture http://designandcode.net/ DesignAndCode software development thoughts.. en-us Design And Code, Inc Tue, 18 Oct 2011 01:25:01 GMT newtelligence dasBlog 2.0.7226.0 MarkMitchell@designandcode.net MarkMitchell@designandcode.net http://designandcode.net/Trackback.aspx?guid=6f955d92-0a1b-4b69-84f5-fd96848a2456 http://designandcode.net/pingback.aspx http://designandcode.net/PermaLink,guid,6f955d92-0a1b-4b69-84f5-fd96848a2456.aspx Mark Mitchell http://designandcode.net/CommentView,guid,6f955d92-0a1b-4b69-84f5-fd96848a2456.aspx http://designandcode.net/SyndicationService.asmx/GetEntryCommentsRss?guid=6f955d92-0a1b-4b69-84f5-fd96848a2456 Quite by accident, I stumbled into Mary Jo Foley's article that mentioned the Microsoft Research Project  Drawbridge - and a Channel9 video on this.
From the Channel 9 description:
Drawbridge is a research prototype of a new form of virtualization for application sandboxing. Drawbridge combines two core technologies: First, a picoprocess, which is a process-based isolation container with a minimal kernel API surface. Second, a library OS, which is a version of Windows enlightened to run efficiently within a picoprocess. Drawbridge combines two ideas from the literature, the picoprocess and the library OS, to provide a new form of computing, which retains the benefits of secure isolation, persistent compatibility, and execution continuity, but with drastically lower resource overheads.

Some time ago, there was an idea of each application having its own Virtual Machine space to run in - and it looks like this is another step toward that goal. Not sure it will make it into Windows 8, but it would not surprise me to see this as part of Windows 9. The Drastically reduced overhead, makes me wonder if they can get this to run on an ARM processor, or phone.

In the video, the indicate that they performed an experiment of running 25 Windows 2008 R2 web servers on a 16GB machine, and then when the switched the Web Servers to use the Drawbridge approach, they were getting "north" of 270 on the same hardware -of course they would have to be very lightly used web sites.

By refactoring the API layers to other modes (pulling Win32k.dll  into a user mode layer - and a usermode version NTUM that communicates through a new "Security Monitor" that exposes only 35 functions to the NTOSKRNL) they reduced the footprint of what is needed - and this could be getting small enough to run on a phone.

The Win32K that expects a Keyboard,  mouse, and clipboard, ends up communicating to a version of the Remote Desktop Server process (on the same machine) that emulates communicating over a network - within the processes - all isolated like a virtual machine. In fact the GUI requires using RDP to the instance that Drawbridge sets up.

Because this is all running stateless - it can save the state of the Drawbridge application - compressed, and send the application to another machine - rehydrate the application state - from any machine that can get to the cloud - due to the sandbox around the application.

It also reduced the threat surface - so it is also a very strong security play.

It is very much a prototype for a small team, and there is a good deal of work to get it to work with GPU processing - e.g. not working with IE9 right now. But it is a very promising direction that I expect to hear more about -hopefully before Windows 10.. :)


New Application Virtualization Sandbox - Drawbridge from Microsoft Research http://designandcode.net/PermaLink,guid,6f955d92-0a1b-4b69-84f5-fd96848a2456.aspx http://designandcode.net/2011/10/18/NewApplicationVirtualizationSandboxDrawbridgeFromMicrosoftResearch.aspx Tue, 18 Oct 2011 01:25:01 GMT Quite by accident, I stumbled into Mary Jo Foley's <a href="http://www.zdnet.com/blog/microsoft/microsoft-goes-public-with-its-drawbridge-operating-system-research-project/11009?tag=mantle_skin;content">article </a>that mentioned the Microsoft Research Project&nbsp; <i>Drawbridge</i> - and a <a href="http://channel9.msdn.com/Shows/Going+Deep/Drawbridge-An-Experimental-Library-Operating-System">Channel9</a> video on this.<br> From the Channel 9 description:<strong> <br> <a href="http://research.microsoft.com/en-us/projects/drawbridge/" target="_blank">Drawbridge is a research prototype</a></strong><em> of a new form of virtualization for application sandboxing. Drawbridge combines two core technologies: First, a <strong>picoprocess</strong>, which is a process-based isolation container with a minimal kernel API surface. Second, a <strong>library OS</strong>, which is a version of Windows enlightened to run efficiently within a picoprocess. Drawbridge combines two ideas from the literature, the <em>picoprocess</em> and the <em>library OS</em>, to provide a new form of computing, which retains the benefits of secure isolation, persistent compatibility, and execution continuity, but with drastically lower resource overheads. </em> <br> <br> Some time ago, there was an idea of each application having its own Virtual Machine space to run in - and it looks like this is another step toward that goal. Not sure it will make it into Windows 8, but it would not surprise me to see this as part of Windows 9. The Drastically reduced overhead, makes me wonder if they can get this to run on an ARM processor, or phone.<br> <br> In the video, the indicate that they performed an experiment of running 25 Windows 2008 R2 web servers on a 16GB machine, and then when the switched the Web Servers to use the Drawbridge approach, they were getting "north" of 270 on the same hardware -of course they would have to be very lightly used web sites.<br> <br> By refactoring the API layers to other modes (pulling Win32k.dll&nbsp; into a user mode layer - and a usermode version NTUM that communicates through a new "Security Monitor" that exposes only 35 functions to the NTOSKRNL) they reduced the footprint of what is needed - and this could be getting small enough to run on a phone. <br> <br> The Win32K that expects a Keyboard,&nbsp; mouse, and clipboard, ends up communicating to a version of the Remote Desktop Server process (on the same machine) that emulates communicating over a network - within the processes - all isolated like a virtual machine. In fact the GUI requires using RDP to the instance that Drawbridge sets up.<br> <br> Because this is all running stateless - it can save the state of the Drawbridge application - compressed, and send the application to another machine - rehydrate the application state - from any machine that can get to the cloud - due to the sandbox around the application.<br> <br> It also reduced the threat surface - so it is also a very strong security play.<br> <br> It is very much a prototype for a small team, and there is a good deal of work to get it to work with GPU processing - e.g. not working with IE9 right now. But it is a very promising direction that I expect to hear more about -hopefully before Windows 10.. :)<br> <br> <br> <p> </p> <img width="0" height="0" src="http://designandcode.net/aggbug.ashx?id=6f955d92-0a1b-4b69-84f5-fd96848a2456" /> http://designandcode.net/CommentView,guid,6f955d92-0a1b-4b69-84f5-fd96848a2456.aspx Architecture Virtualization http://designandcode.net/Trackback.aspx?guid=de6511fb-497f-483a-8ee0-d5ee427172d7 http://designandcode.net/pingback.aspx http://designandcode.net/PermaLink,guid,de6511fb-497f-483a-8ee0-d5ee427172d7.aspx Mark Mitchell http://designandcode.net/CommentView,guid,de6511fb-497f-483a-8ee0-d5ee427172d7.aspx http://designandcode.net/SyndicationService.asmx/GetEntryCommentsRss?guid=de6511fb-497f-483a-8ee0-d5ee427172d7 In 2008, I attended the Microsoft Professionals meeting (Atlanta) where Shawn Wildermuth gave a presentation on Domain specific languages or DSL's. The concepts were an introduction into a Microsoft product development that used the code names   "OSLO",  "M", and "Quadrant" that was previewed in part at the PDC2008 (Professional Developer Conference) which has mostly morphed into something else by PDC2009. Shawn produced three articles for MSDN on the topics of "OSLO" and "M". In the 2008 presentation I attended, Shawn introduced the premise that we use DSL's already today; SQL, XAML, Make, Ant/Nant, MSBuild, regular-expressions, even musical notation are all examples of DSL's. From that talk, the idea of software development DSL's  was planted - even though the technologies that had prompted his discussion have been morphed into new forms within Microsoft - the conclusion  from this argument is that a set of text statements ( or specific symbols like music or regular expressions) can be declared and used to achieve a desired result - and within programming - results in how executing code processes those results. A concise grammar and syntax, that declares what you want to do but not how you do accomplish that - regular expression syntax is a great example. Software development using a DSL, is an idea that continues to cross my path. I thought I would try to capture some of the variations I have seen in how various developers and architects approach the concept of creating and using DSLs.

Martin Fowler wrote the book on Domain Specific Languages where he describes the 3 types of DSLs.
There are some early Oslo software preview videos out on the Microsoft site that show the language M being used to generate a DSL grammar within the tool called Quadrant. This is what Martin Fowler referred to as a "DSL workbench"- where the tool builds the DSL. Martin Fowler identified two other main categories of DSL; the External DSL, and the Internal, or Embedded DSL. External DSL's are often quite complex - and rarely come to general usage. Internal, or Embedded DSL's are abstractions over an API, or framework, within an application.

The idea of a DSL being used was briefly touched on in the Jan 2009 DotNet Rocks episode with Aslam Khan a software architect that lives in South Africa. The company he works with uses this to achieve Domain Driven Design (DDD). "Write a story that describes a problem", and understand that little piece, to understand the domain. "Something that describes it completely - that does not bleed into the other", which build up a dependency graph, it exists in context to the other things - behind each story. A story about the problem - the domain. The more you reveal incorrect assumptions in the dependency graphs and correct them, you don't have to prune source code trees -so you get smaller source code trees, and designing API's around the stories - means changing the granularity of the stories - not modules. In the podcast (just after 38:41) they describe a misunderstood story - that would have produced an incorrect system design - but writing out a story, that the users can understand - allows for corrections can be made before hand. Understanding the user's vocabulary, and you can write it in those terms, then you have the basis to build on(this goes back to the Eric Evan's Domain-Driven-Design "ubiquitous language"). It helps other people later on to understand the language of the application. Aslam Khan uses a Wiki to capture that language - and refers to the "Wiki as code" (about 44:44 in the podcast). He refers to it as "a DSL captured in business terms - that cannot be executed - but at that point you can start writing code". After listening to that podcast(in 2009), I went to Aslam's website - and discovered his posting about using Cucumber and driving it down into Rspec. That led to my reading of a post about Ruby and the latest on Ruby testing - using cucumber. (There is a language called Gherkin used with Cucumber to create a Ruby testing framework). The dynamic nature of Ruby - and the concept of Metaprogramming - became connected to the idea of how one could produce a DSL. Aslam Khan stated it, on his blog, as "the Code is the data" behind a DSL, and he encouraged learning about AST's (Abstract Syntax Trees) which to me connected directly to .Net Expression Trees - the basis of Microsoft Dynamic Language Runtime(DLR) in .Net 4.0.  DSL's can become Expression Trees which in turn can become running code in the DLR. At least, in theory, that would be one Dynamic-Language approach to implementing a DSL(There may be some limitations on how that can occur).
 
During 2010, I picked up a copy of Orin Eini's(a.k.a Ayende Rahein) book called "DSL's in Boo - Domain Specific Languages in .Net". (he did an interview in March 2010 with DotNetRocks on this topic).Ayende is known in the .Net development world for RhinoMocks( a mocking framework), his work on NHibernate(his company makes a profiler for NHibernate and EntityFrameworks), and now his RavenDB - document database project. Somehow, he also managed to have written a book on DSL's   - the guy is prolific at producing content - whether you see his coding output(RhinoMocks,RavenDB), his blog, and now his book.  In his book, he describes how he builds his own DSL's using the .Net language Boo as the foundation, as it gives him a parser,lexer, and great extensibility points, that compile into .Net code - that is not based on the DLR. He shows how the Boo language allows for defining your own expressions that can then be compiled - statically.  Boo is based on the released ECMA standard for the CLI. Interestingly -both the Boo Language, and the ECMA CLI standard, had recent updates(at this writing) Boo 0.9.4 was updated Jan 2011, and the ECMA Standard December 2010. Boo has some capacities that make the language very powerful. It can be an object oriented language, and it can do functional composition (where functions are first class citizens like those in F#), it has 'Syntactic Macros', and it has an extensible compilation pipeline - which is what the creator, Rodrigo B. de Oliveira, wanted to have in the first place, and it can run on multiple platforms (Windows CLR and Linux Mono). Boo has its roots  based on Python Syntax and looks like it has some great potential.  To use Boo that as the basis for creating a DSL seems like a very interesting choice - here it would be a statically typed implementation of a DSL. This could be a way of generating a concise Internal, or External, DSL that works for the users and programmers alike within a given domain. Ayende's book gets into the details of using boo for creating your own DSL.

I found a few entries that related how Powershell could be used at the basis of a DSL. There is a blog post from Keith Hill on how Powershell's syntax flexibility allows you to create a internal DSL. Doug Finke, a Powershell MVP, posted something that went back to the Oslo starting point from a Powershell point of view. Doug Finke shows implementing an OSLO grammar syntax using Powershell, based on the concepts originally introduced in that early video of the M Language example. So from Dynamic Languages or Scripting tools we can find approaches to creating DSL's today.  Doug Finke connected the concepts of DSL, DRL, and Boo; all the ideas together in his post "Creating a unified programming model on top of .NET" He cites "Trends and Directions in programming languages" from Anders Hejlsberg.  DSL's could certainly be part of that mix in creating solutions.

Jeffrey Snover, the architect of Powershell, had a discussion in 2008 on DSL's with Martin Fowler and Neal Ford from Thoughtworks. (recording on Channel9). In this talk they made the point that a DSL can be an External DSL, an Internal DSL or a 'workbench' with tools wrapped around it. Martin Fowler made the point that not many successful DSL's have been done starting from the business side and working toward the API - but that is where the concept is the most powerful, they made the point that it is usually an abstraction of an existing API that simplifies the underlying API - and that DSL can be replaced with the word 'Framework' and mean the same thing. Jeffrey Snover also posted that Powershell could be used to create DSL's by limiting the syntax. The key piece he refers to is the data segment SupportedCommands - which he alludes to as a way to limit a DSL done in Powershell.

Karl Prosser referred to the Powerboots library for Powershell as a DSL in a blog post. It is a Powershell set of commands that are specific to using WPF from within Powershell - which stays with the concept that it  is limited to that specific domain.

Sometimes the use of a Fluent API - can be used to write code that is very readable and expressive - such that it becomes an internal DSL within the general purpose language(Steven Hoisee blog has some coverage on this).  I came accross a paper on how JMock was developed and how they worked toward incorporating a Fluent API as part of their own Embeded DSL within the framework.

Martin Fowler, who took the time to write the book on DSL, has a post on BusinessReadableDSLs. Where the idea is different than business-writeable DSLs. That was the impression I got from Aslam Khan's use of Cucumber - that the business could read the DSL and confirm if it was correct or not.
Martin Fowler invokes the comparison to COBOL - which was supposed to be an english way of telling the computer what to do - and begs the question - how is this one different?  My impression is that the a correct implementation of a DSL is declarative - it describes what you want to do, now how you do it - and having programmed in COBOL - it is an imperative approach, not a declarative one.

Developing a DSL, based on the Jeffrey Snover video, leads me to see that in a DSL you have vocabulary and you have grammar that must be decided on - and the idea of keeping it small seems to be important. Just enough to keep and simple - and no simpler.

Jeremy Miller(Creator of the IOC container - StructureMap, an MVC framework called FubuMVC, and a testing tool called StoryTeller) did a presentation on creating Internal DSL's at Oredev in Oslo - Nov 2010.
He  contributed to the Fluent NHibernate project, and incorporated the use of an Internal DSL in these projects - and in the presentation he goes over some of the difficulties of using and developing an Internal DSL using the C# 3.0 language features. He touches on the separation of the Runtime and Configuration model in building a DSL, and that testing an internal DSL for configuration is very difficult - you can test the runtime model more easily, and then make sure your configuration model works correctly. (the video is a bit grainy - and a few of the questions, that came from the audience, are not heard - but the concepts that were used in creating an internal DSL are shown pretty well.)

From this set of touch points - on the various flavors of DSL's, it is something that can be done in a variety of ways. The simplest form is the internal or embedded, perhaps as a Fluent API approach. This simple form of a DSL can be for a small team that produces repetitive code, or business rules that are needed in in either a static or dynamic fashion - but still being an internal abstraction - within a small domain. Then there is an external DSL - and that would need to have a the same considerations as a full blown computer language - as the publishing of an External DSL approach tends to get the syntax set in stone, unless you can absorb breaking changes later on. 

I find this an interesting research topic, that may prove to be a practical solution to some future area of work. Along these lines - I recently purchased a book that looks promising; Terrence Parr's book "Language Implementation Patterns - Create your own Domain Specific and General Programming Languages". Terrence Parr developed  ANTLR and that tool is used in the Boo compiler.  I will have more reading and learning to do in this area - and, perhaps at some point, the payoff will be when I can see an area where a DSL can be used to invoke parts of a framework. Ideally this would be in terms of the users, a readable Business DSL, or an API syntax that developers for an application can use that brings a higher level of abstraction and makes code more readable - and perhaps more declarative.  The Jeremy Miller video shows that is not a simple task, however, he shows that it can be used to develop some powerful solutions too, and that I find to be valuable.

Research - DSL Domain Specific Language concept and application http://designandcode.net/PermaLink,guid,de6511fb-497f-483a-8ee0-d5ee427172d7.aspx http://designandcode.net/2011/01/26/ResearchDSLDomainSpecificLanguageConceptAndApplication.aspx Wed, 26 Jan 2011 01:05:47 GMT In 2008, I attended the Microsoft Professionals meeting (Atlanta) where <a href="http://wildermuth.com/">Shawn Wildermuth</a> gave a presentation on Domain specific languages or DSL's. The concepts were an introduction into a Microsoft product development that used the code names &nbsp; "OSLO",&nbsp; "M", and "Quadrant" that was previewed in part at the PDC<a href="http://channel9.msdn.com/Blogs/pdc2008/TL31">2008</a> (Professional Developer Conference) which has mostly morphed into something else by PDC2009. Shawn produced three <a href="http://wildermuth.com/2009/06/09/My_Oslo_DSL_Article_Part_1_is_Updated_for_May_2009_CTP">articles</a> for MSDN on the topics of "OSLO" and "M". In the 2008 presentation I attended, Shawn introduced the premise that we use DSL's already today; SQL, XAML, Make, Ant/Nant, MSBuild, regular-expressions, even musical notation are all examples of DSL's. From that talk, the idea of software development DSL's&nbsp; was planted - even though the technologies that had prompted his discussion have been morphed into new forms within Microsoft - the conclusion&nbsp; from this argument is that a set of text statements ( or specific symbols like music or regular expressions) can be declared and used to achieve a desired result - and within programming - results in how executing code processes those results. A concise grammar and syntax, that declares what you want to do but not how you do accomplish that - regular expression syntax is a great example. Software development using a DSL, is an idea that continues to cross my path. I thought I would try to capture some of the variations I have seen in how various developers and architects approach the concept of creating and using DSLs.<br> <br> Martin Fowler wrote the book on <a href="http://www.amazon.com/Domain-Specific-Languages-Addison-Wesley-Signature-Fowler/dp/0321712943/">Domain Specific Languages</a> where he describes the 3 types of DSLs.<br> There are some early Oslo software preview <a href="http://msdn.microsoft.com/en-us/data/dd576258.aspx">videos</a> out on the Microsoft site that show the language M being used to generate a DSL grammar within the tool called Quadrant. This is what Martin Fowler referred to as a "DSL workbench"- where the tool builds the DSL. Martin Fowler identified two other main categories of DSL; the External DSL, and the Internal, or Embedded DSL. External DSL's are often quite complex - and rarely come to general usage. Internal, or Embedded DSL's are abstractions over an API, or framework, within an application. <br> <br> The idea of a DSL being used was briefly touched on in the Jan 2009 DotNet Rocks <a href="http://www.dotnetrocks.com/default.aspx?showNum=415">episode</a> with <a href="http://aslamkhan.net/">Aslam Khan</a> a software architect that lives in South Africa. The company he works with uses this to achieve <a href="http://domaindrivendesign.org/resources/what_is_ddd">Domain Driven Design</a> (DDD). "Write a story that describes a problem", and understand that little piece, to understand the domain. "Something that describes it completely - that does not bleed into the other", which build up a dependency graph, it exists in context to the other things - behind each story. A story about the problem - the domain. The more you reveal incorrect assumptions in the dependency graphs and correct them, you don't have to prune source code trees -so you get smaller source code trees, and designing API's around the stories - means changing the granularity of the stories - not modules. In the podcast (just after 38:41) they describe a misunderstood story - that would have produced an incorrect system design - but writing out a story, that the users can understand - allows for corrections can be made before hand. Understanding the user's vocabulary, and you can write it in those terms, then you have the basis to build on(this goes back to the Eric Evan's Domain-Driven-Design <a href="http://books.google.com/books?id=7dlaMs0SECsC&amp;pg=PA24&amp;lpg=PA24&amp;dq=eric+evans+domain+driven+design+ubiquitous+language&amp;source=bl&amp;ots=ulHUY1U8s8&amp;sig=jk96fBqxm3-SYbPZPtb8gev_VAk&amp;hl=en&amp;ei=H-JBTZvcLYbagAfM59mWAg&amp;sa=X&amp;oi=book_result&amp;ct=result&amp;resnum=8&amp;ved=0CEkQ6AEwBw#v=onepage&amp;q&amp;f=false">"ubiquitous language"</a>). It helps other people later on to understand the language of the application. Aslam Khan uses a Wiki to capture that language - and refers to the "Wiki as code" (about 44:44 in the podcast). He refers to it as "a DSL captured in business terms - that cannot be executed - but at that point you can start writing code". After listening to that podcast(in 2009), I went to Aslam's website - and discovered his <a href="http://aslamkhan.net/software-development/heck-we-should-have-paid-attention-that-day/">posting</a> about using Cucumber and driving it down into <a href="http://www.pragprog.com/titles/achbd/the-rspec-book">Rspec</a>. That led to my reading of a post about Ruby and the latest on <a href="http://www.rubyinside.com/cucumber-the-latest-in-ruby-testing-1342.html">Ruby testing - using cucumber</a>. (There is a language called <a href="https://github.com/aslakhellesoy/cucumber/wiki/Gherkin">Gherkin</a> used with Cucumber to create a <a href="http://bjarte.com/post/228763457">Ruby testing framework</a>). The dynamic nature of Ruby - and the concept of Metaprogramming - became connected to the idea of how one could produce a DSL. Aslam Khan stated it, on his blog, as "the Code is the data" behind a DSL, and he encouraged learning about AST's (Abstract Syntax Trees) which to me connected directly to .Net Expression Trees - the basis of Microsoft Dynamic Language Runtime(DLR) in .Net 4.0.&nbsp; DSL's can become Expression Trees which in turn can become running code in the DLR. At least, in theory, that would be one Dynamic-Language approach to implementing a DSL(There may be some limitations on how that can occur).<br> &nbsp; <br> During 2010, I picked up a copy of Orin Eini's(a.k.a <a href="http://www.ayende.com/">Ayende Rahein</a>) book called "<a href="http://www.amazon.com/DSLs-Boo-Domain-Specific-Languages/dp/1933988606/">DSL's in Boo</a> - Domain Specific Languages in .Net". (he did an <a href="http://www.dotnetrocks.com/default.aspx?ShowNum=529">interview</a> in March 2010 with DotNetRocks on this topic).Ayende is known in the .Net development world for RhinoMocks( a mocking framework), his work on NHibernate(his company makes a profiler for NHibernate and EntityFrameworks), and now his RavenDB - document database project. Somehow, he also managed to have written a book on DSL's &nbsp; - the guy is prolific at producing content - whether you see his coding output(RhinoMocks,RavenDB), his blog, and now his book.&nbsp; In his book, he describes how he builds his own DSL's using the .Net language <a href="http://boo.codehaus.org/">Boo</a> as the foundation, as it gives him a parser,lexer, and great extensibility points, that compile into .Net code - that is not based on the DLR. He shows how the Boo language allows for defining your own expressions that can then be compiled - statically.&nbsp; Boo is based on the released <a href="http://www.ecma-international.org/publications/standards/Ecma-335.htm">ECMA standard for the CLI</a>. Interestingly -both the Boo Language, and the ECMA CLI standard, had recent updates(at this writing) Boo 0.9.4 was updated Jan 2011, and the ECMA Standard December 2010. Boo has some capacities that make the language very powerful. It can be an object oriented language, and it can do functional composition (where functions are first class citizens like those in F#), it has '<a href="http://ayende.com/Blog/archive/2008/05/27/The-magic-of-boo--Flexible-syntax.aspx">Syntactic Macros'</a>, and it has an extensible compilation pipeline - which is what the creator, Rodrigo B. de Oliveira, wanted to have in the first place, and it can run on multiple platforms (Windows CLR and Linux Mono). Boo has its roots&nbsp; based on Python Syntax and looks like it has some great potential.&nbsp; To use Boo that as the basis for creating a DSL seems like a very interesting choice - here it would be a statically typed implementation of a DSL. This could be a way of generating a concise Internal, or External, DSL that works for the users and programmers alike within a given domain. Ayende's book gets into the details of using boo for creating your own DSL.<br> <br> I found a few entries that related how Powershell could be used at the basis of a DSL. There is a blog <a href="http://keithhill.spaces.live.com/Blog/cns%215A8D2641E0963A97%216944.entry">post</a> from Keith Hill on how Powershell's syntax flexibility allows you to create a internal DSL. Doug Finke, a Powershell MVP, posted something that went back to <a href="http://www.dougfinke.com/blog/index.php/2009/07/01/powershell-powerboots-and-an-oslo-dsl-grammar/">the Oslo starting point</a> from a Powershell point of view. Doug Finke shows implementing an OSLO grammar syntax using Powershell, based on the concepts originally introduced in that early video of the M Language example. So from Dynamic Languages or Scripting tools we can find approaches to creating DSL's today.&nbsp; Doug Finke connected the concepts of DSL, DRL, and Boo; all the ideas together in his post <a temp_href="Creating a unified programming model on top of .NET" href="Creating%20a%20unified%20programming%20model%20on%20top%20of%20.NET">"<font size="3">Creating a unified programming model on top of .NET"</font></a> He cites "Trends and Directions in programming languages" from Anders Hejlsberg.&nbsp; DSL's could certainly be part of that mix in creating solutions.<br> <br> Jeffrey Snover, the architect of Powershell, had a discussion in 2008 on DSL's with Martin Fowler and Neal Ford from Thoughtworks. (<a href="http://channel9.msdn.com/blogs/charles/jeffrey-snover-martin-fowler-and-neil-ford-domain-specific-languages">recording on Channel9</a>). In this talk they made the point that a DSL can be an External DSL, an Internal DSL or a 'workbench' with tools wrapped around it. Martin Fowler made the point that not many successful DSL's have been done starting from the business side and working toward the API - but that is where the concept is the most powerful, they made the point that it is usually an abstraction of an existing API that simplifies the underlying API - and that DSL can be replaced with the word 'Framework' and mean the same thing. Jeffrey Snover also <a href="http://blogs.msdn.com/b/powershell/archive/2008/10/09/domain-specific-languages-dsls-in-general-and-how-powershell-relates.aspx">posted</a> that Powershell could be used to create DSL's by limiting the syntax. The key piece he refers to is the <a href="http://technet.microsoft.com/en-us/library/dd347678.aspx">data segment SupportedCommands</a> - which he alludes to as a way to limit a DSL done in Powershell.<br> <br> Karl Prosser referred to the Powerboots library for Powershell as a DSL in a <a href="http://powershell.com/cs/blogs/karl-prosser/archive/2009/02/11/powerboots-a-beautiful-dsl-not-to-mention-useful.aspx">blog post</a>. It is a Powershell set of commands that are specific to using WPF from within Powershell - which stays with the concept that it&nbsp; is limited to that specific domain.<br> <br> Sometimes the use of a Fluent API - can be used to write code that is very readable and expressive - such that it becomes an internal DSL within the general purpose language(Steven Hoisee <a href="http://www.blog.holsee.com/2009/10/fluent-interfaces-internal-domain-specific-languages/">blog</a> has some coverage on this).&nbsp; I came accross a paper on how JMock was developed and how they worked toward incorporating a Fluent API as part of their own <a href="http://static.mockobjects.com/files/evolving_an_edsl.ooplsa2006.pdf">Embeded DSL</a> within the framework.<br> <br> Martin Fowler, who took the time to write the book on DSL, has a post on <a href="http://www.martinfowler.com/bliki/BusinessReadableDSL.html">BusinessReadableDSLs</a>. Where the idea is different than business-writeable DSLs. That was the impression I got from Aslam Khan's use of Cucumber - that the business could read the DSL and confirm if it was correct or not. <br> Martin Fowler invokes the comparison to COBOL - which was supposed to be an english way of telling the computer what to do - and begs the question - how is this one different?&nbsp; My impression is that the a correct implementation of a DSL is declarative - it describes what you want to do, now how you do it - and having programmed in COBOL - it is an imperative approach, not a declarative one.<br> <br> Developing a DSL, based on the Jeffrey Snover video, leads me to see that in a DSL you have vocabulary and you have grammar that must be decided on - and the idea of keeping it small seems to be important. Just enough to keep and simple - and no simpler.<br> <br> Jeremy Miller(Creator of the IOC container - StructureMap, an MVC framework called FubuMVC, and a testing tool called StoryTeller) did a <a href="http://oredev.org/2010/sessions/patterns-for-building-internal-dsls-in-c-3-0">presentation</a> on creating Internal DSL's at Oredev in Oslo - Nov 2010.<br> He&nbsp; contributed to the Fluent NHibernate project, and incorporated the use of an Internal DSL in these projects - and in the presentation he goes over some of the difficulties of using and developing an Internal DSL using the C# 3.0 language features. He touches on the separation of the Runtime and Configuration model in building a DSL, and that testing an internal DSL for configuration is very difficult - you can test the runtime model more easily, and then make sure your configuration model works correctly. (the video is a bit grainy - and a few of the questions, that came from the audience, are not heard - but the concepts that were used in creating an internal DSL are shown pretty well.)<br> <br> From this set of touch points - on the various flavors of DSL's, it is something that can be done in a variety of ways. The simplest form is the internal or embedded, perhaps as a Fluent API approach. This simple form of a DSL can be for a small team that produces repetitive code, or business rules that are needed in in either a static or dynamic fashion - but still being an internal abstraction - within a small domain. Then there is an external DSL - and that would need to have a the same considerations as a full blown computer language - as the publishing of an External DSL approach tends to get the syntax set in stone, unless you can absorb breaking changes later on.&nbsp; <br> <br> I find this an interesting research topic, that may prove to be a practical solution to some future area of work. Along these lines - I recently purchased a book that looks promising; <a href="http://www.cs.usfca.edu/%7Eparrt/">Terrence Parr</a>'s book "<a href="http://www.amazon.com/Language-Implementation-Patterns-Domain-Specific-Programming/dp/193435645X">Language Implementation Patterns</a> - Create your own Domain Specific and General Programming Languages". Terrence Parr developed&nbsp; <a href="http://www.antlr.org/">ANTLR</a> and that tool is used in the Boo compiler.&nbsp; I will have more reading and learning to do in this area - and, perhaps at some point, the payoff will be when I can see an area where a DSL can be used to invoke parts of a framework. Ideally this would be in terms of the users, a readable Business DSL, or an API syntax that developers for an application can use that brings a higher level of abstraction and makes code more readable - and perhaps more declarative.&nbsp; The Jeremy Miller video shows that is not a simple task, however, he shows that it can be used to develop some powerful solutions too, and that I find to be valuable.<br> <p> </p> <img width="0" height="0" src="http://designandcode.net/aggbug.ashx?id=de6511fb-497f-483a-8ee0-d5ee427172d7" /> http://designandcode.net/CommentView,guid,de6511fb-497f-483a-8ee0-d5ee427172d7.aspx .Net Architecture ComputerLanguages Cucumber DDD DesignSpecifcLanguage(DSL) DevelopmentTools Gherkin Powershell Ruby Software Frameworks Structuremap http://designandcode.net/Trackback.aspx?guid=178a3b4e-7f94-48e2-af66-efe61be00fd2 http://designandcode.net/pingback.aspx http://designandcode.net/PermaLink,guid,178a3b4e-7f94-48e2-af66-efe61be00fd2.aspx Mark Mitchell http://designandcode.net/SyndicationService.asmx/GetEntryCommentsRss?guid=178a3b4e-7f94-48e2-af66-efe61be00fd2

Codestock 2009 wrapped up last night.The event was oversold by 1 - 376 attendees. I enjoyed the selection of talks that were available, and the sessions I attended were good. Of course I had a favorite.

My Favorite session was delivered Rik Robinson of Wintellect. His talk was on PRISM, from the Microsoft Patterns and Practice group (PNP), this is a Guidance that can be used in WPF and Silverlight - and incorporates the Unity IOC framework (but that can be swapped out if you prefer). He kept it simple, he introduced one thing built on another, and he got the main concepts of how PRISM can be used to develop applications that decouple View and ViewModel in a very clean fasion. The session was very interactive and it must have been a bit of pressure to have the Wintellect CEO sitting in the session.

Through another acquaintance I got to have dinner with Rik that night(day of his presentation), and hooked up with him for yet another dinner after the last Codestock session before driving back (we did not attend the giveaways).

Wintellect is local to Knoxville, and is one of the supporters of Codestock. They arranged to have to other presentations besides Rik Robinson's. John Robbins and Jeffrey Richter gave presentations via live meeting - and took questions via cell phone (which you would hear in the room as an echo - but it worked). I attended the John Robbins debugging presentation and it too was excellent (he can make technology humourous) - I picked another session instead of the Jeffrey Richter session - if they recorded it I am going to go watch it.

I feel a bit responsible for a comment from another attendee about one session I attended. The session just seemed like there were more examples that were ready - but not shown - and the session ended earlier than the time slot. I overheard someone else make that comment about it - and it seemed to fit. I had been fine with how it was -and only when I heard the comment did it occur to me that not all of the examples had been touched on. I had sat down to lunch with this speaker before his presentation. It occurred to me that I may have impacted his preparation, and even the thought that I did impact his presentation makes me feel sorry for having disturbed his preparation. I felt it was still a good presentation. I heard how much Rik Robinson prepared and saw the result - it is a lot of work - and it makes me wonder if my trying to be social - was just at the wrong time (My apologies to the speaker)

There were several topic areas of interest for me during codestock. WPF,PRISM, MEF, Debugging, WCF, ORM usage, and TDD. There were sessions that touched on, or spoke to these - and much more.

Another acquaintance suggested I attend Kevin Hazzard's session on "How I learned to love Metaprogramming" - which was a very good look into the way that the compiler creates a dynamic data type in .Net 4.0. The data type of dynamic - is static. That statement seems at first to be an oxymoron - but the element is treated as static and how it resolves at runtime is dynamic. The presentation showed how C# and Python could interact - and gave some examples of dynamically wrapping elements of XML using C# using the Dynamic elements. His XML Example reminded me of something that Powershell can do today - and Kevin said that the powershell team did not go down the Dynamic Language path - which he was not pleased with. Kevin Hazzard is a very good speaker and he gets into the topic very deeply - and explains it well. I would like to hear more about his perceptions on Powershell, and how he thinks it might have been done.

There was one connection that I did not expect to occur. At the CodeStock social event, I was sitting at a table, and a fellow walked over and looked at me and said - I think I know you. After a moment or two - I recogognized him from a twitter photo. When I went to Devlink 2008 - I was trying to use Twitter to find out where people were meeting up, and I had been on twitter for maybe a month at that time. This fellow was not able to attend the DevLink event - but was trying to follow what was going on - and he responded to help me figure out where people would be. Between this fellow and "TheCodeCampJunkie" - I was able to hook up with people at DevLink. So here was my first time meeting a person face to face - based on using twitter. We talked about .Net and his getting certified and how it was not helping him get work.

The main focus of these event is the dissemenation of knowledge of what is new and how to use the technology we deal with. The other part of this is that you are meeting and speaking with other developers, whom you may have not ever met otherwise.

Several people have posted pictures from CodeStock - Alan Barber got one picture of me at the Dinner on the night before the event.

Codestock 2009 http://designandcode.net/PermaLink,guid,178a3b4e-7f94-48e2-af66-efe61be00fd2.aspx http://designandcode.net/2009/06/28/Codestock2009.aspx Sun, 28 Jun 2009 12:37:48 GMT <p> Codestock 2009 wrapped up last night.The event was oversold by 1 - 376 attendees. I enjoyed the selection of talks that were available, and the sessions I attended were good. Of course I had a favorite. </p> <p> My Favorite session was delivered Rik Robinson of Wintellect. His talk was on <a href="http://www.codeplex.com/Wiki/View.aspx?ProjectName=CompositeWPF">PRISM</a>, from the Microsoft Patterns and Practice group (PNP), this is a Guidance that can be used in WPF and Silverlight - and incorporates the Unity IOC framework (but that can be swapped out if you prefer). He kept it simple, he introduced one thing built on another, and he got the main concepts of how PRISM can be used to develop applications that decouple View and ViewModel in a very clean fasion. The session was very interactive and it must have been a bit of pressure to have the Wintellect CEO sitting in the session. </p> <p> Through another acquaintance I got to have dinner with Rik that night(day of his presentation), and hooked up with him for yet another dinner after the last Codestock session before driving back (we did not attend the giveaways). </p> <p> Wintellect is local to Knoxville, and is one of the supporters of Codestock. They arranged to have to other presentations besides Rik Robinson's. John Robbins and Jeffrey Richter gave presentations via live meeting - and took questions via cell phone (which you would hear in the room as an echo - but it worked). I attended the John Robbins debugging presentation and it too was excellent (he can make technology humourous) - I picked another session instead of the Jeffrey Richter session - if they recorded it I am going to go watch it. <p> I feel a bit responsible for a comment from another attendee about one session I attended. The session just seemed like there were more examples that were ready - but not shown - and the session ended earlier than the time slot. I overheard someone else make that comment about it - and it seemed to fit. I had been fine with how it was -and only when I heard the comment did it occur to me that not all of the examples had been touched on. I had sat down to lunch with this speaker before his presentation. It occurred to me that I may have impacted his preparation, and even the thought that I did impact his presentation makes me feel sorry for having disturbed his preparation. I felt it was still a good presentation. I heard how much Rik Robinson prepared and saw the result - it is a lot of work - and it makes me wonder if my trying to be social - was just at the wrong time (My apologies to the speaker) </p> <p> There were several topic areas of interest for me during codestock. WPF,PRISM, MEF, Debugging, WCF, ORM usage, and TDD. There were sessions that touched on, or spoke to these - and much more. </p> <p> Another acquaintance suggested I attend Kevin Hazzard's session on "How I learned to love Metaprogramming" - which was a very good look into the way that the compiler creates a <i>dynamic</i> data type in .Net 4.0. The data type of dynamic - is static. That statement seems at first to be an oxymoron - but the element is treated as static and how it resolves at runtime is dynamic. The presentation showed how C# and Python could interact - and gave some examples of dynamically wrapping elements of XML using C# using the Dynamic elements. His XML Example reminded me of something that Powershell can do today - and Kevin said that the powershell team did not go down the Dynamic Language path - which he was not pleased with. Kevin Hazzard is a very good speaker and he gets into the topic very deeply - and explains it well. I would like to hear more about his perceptions on Powershell, and how he thinks it might have been done. </p> <p> There was one connection that I did not expect to occur. At the CodeStock social event, I was sitting at a table, and a fellow walked over and looked at me and said - I think I know you. After a moment or two - I recogognized him from a twitter photo. When I went to Devlink 2008 - I was trying to use Twitter to find out where people were meeting up, and I had been on twitter for maybe a month at that time. This fellow was not able to attend the DevLink event - but was trying to follow what was going on - and he responded to help me figure out where people would be. Between this fellow and "TheCodeCampJunkie" - I was able to hook up with people at DevLink. So here was my first time meeting a person face to face - based on using twitter. We talked about .Net and his getting certified and how it was not helping him get work. </p> <p> The main focus of these event is the dissemenation of knowledge of what is new and how to use the technology we deal with. The other part of this is that you are meeting and speaking with other developers, whom you may have not ever met otherwise. </p> <p> Several people have posted pictures from CodeStock - Alan Barber got one picture of <a href="http://cid-67d16e3143fa2957.skydrive.live.com/self.aspx/Codestock%202009/IMG%7C_0135.jpg">me</a> at the Dinner on the night before the event. </p> <ul> Photo collections from Code Stock Attendees <li> <a href="http://cid-67d16e3143fa2957.skydrive.live.com/browse.aspx/Codestock%202009">Alan Barber</a> </li> <li> <a href="http://www.flickr.com/photos/scoregasm/sets/72157620686419596/">Michael Neel</a> </li> <li> <a href="http://www.flickr.com/photos/29942169@N08/sets/72157620739255234/">David Giard</a> </li> </ul> <img width="0" height="0" src="http://designandcode.net/aggbug.ashx?id=178a3b4e-7f94-48e2-af66-efe61be00fd2" /> http://designandcode.net/CommentView,guid,178a3b4e-7f94-48e2-af66-efe61be00fd2.aspx .Net Architecture CodeCamp DevelopmentTools Inversion-of-Control ProfessionalNetwork Software Frameworks Twitter