Build Your Own Designer An Introduction to Visual Studio DSL Tools

1. Ivan Towlson Mindscape Build Your Own DesignerAn Introduction to Visual Studio DSL Tools

2. Agenda • What are DSLs and why should I care? • What are the Visual Studio DSL Tools? • Building a DSL • Vocabulary and grammar • Spiffing it up • Using the DSL • Distributing your DSL

3. Domain-Specific Languages • A vocabulary and grammar tailored to a particular field of use • SQL – a DSL for manipulating relational data • Regex notation – a DSL for text matching • Mathematica – a DSL for symbolic mathematics • BPMN – a DSL for business processes • LINQ designer – a DSL for mapping SQL tables • Windows Forms designer?! VS class diagrams? UML!

4. Classifying DSLs • Internal or external – a vocabulary within the host language (e.g. fluent APIs) or a separate language • Textual or graphical • Vertical or horizontal – a specific business (e.g. a DSL for rail networks) or a technical area (e.g. SQL, regex)

5. “I was researching implementation techniques for graphical DSLs in vertical domains”

6. When Would You Create One? • You are addressing a well-defined problem area • The problem area supports a more concise expression than “longhand” programming • You need the flexibility to express a range of problems, situations or solutions within that area • The people you expect to use your language have the analytical and technical skills to express their problems in a way a dumb computer can handle

7. Visual Studio DSL Tools • A kit for hosting graphical DSLs within Visual Studio

8. Consequences • Users must have a Visual Studio licence • Users must not freak out when they see the Visual Studio UI • Models must be hosted within Visual Studio projects • Therefore typically not aimed at end users

9. Example: LightSpeed • Domain modelling tool / object-relational mapper • User base: .NET developers • Core concepts: entities with attributes and associations between them • Convention over configuration • Entity classes typically follow standard formula • Predictable mapping between objects and tables

10. public class Contribution : Entity<int> { private string _title; public string Title { get { return _title; } set { Set(ref _title, value, "Title"); } } }

11. public class Contribution: Entity<int> { private string _title; public string Title { get { return _title; } set { Set(ref _title, value, "Title"); } } }

12. Enough talk! Show me code!

13. Using the Model • At compile time – code generation • At runtime – as just another object

14. Code Generation Options

15. Distribution • DSL and Package DLLs • .vstemplate • .xsd • Optional custom tool • No redistributables required for VS2008 • Must install free redistributables for VS2005 • DSL Tools includes rudimentary MSI generator

16. Distribution • Package load key • Free from VSIP program • Attributes must match DLL – new version, new PLK! “The most common cause of package load failures.” • Branding: register under InstalledPackages key • The curse of devenv /setup

17. Visual Studio Extensibility homepage: http://msdn.microsoft.com/en-us/vsx/default.aspx

18. Thanks! • Cook, Jones, Kent & Wills, “Domain Specific Development with Visual Studio DSL Tools” • Same authors’ blogs on blogs.msdn.com • VSX developer centre on MSDN • Clarius T4 Editor ivan@mindscape.co.nz http://www.mindscape.co.nz ivan@hestia.cc http://hestia.typepad.com/flatlander