Graph visualization is a way of representing structural information as diagrams of abstract graphs and networks. Automatic graph drawing has many important applications in software engineering, database and web design, networking, and in visual interfaces for many other domains.

The Little Language

New-DiGraph { Add-Edge Node1 Node2 edge } | Out-Graphviz -dot c:\sample.png -show

This little language has, New-DiGraph, Add-Edge and Out-Graphviz. Plus there is a PowerShell script block, denoted by the {}, that is being passed as a parameter to New-DiGraph. These functions form the DSL/DSV (domain specific vocabulary).

The PowerShell below shows an implementation of the New-DiGraph and Add-Edge functions. Add-Edge, which is passed to New-DiGraph in a script block (see above), gets executed in the line & $sb.

Function New-DiGraph {
    param (
        [scriptblock]$sb
    )            

     Function Add-Edge {
        param($source, $target, $edgeLabel)
        "$source -> $target [ label = `"$edgeLabel`" ]"
    }            

    & $sb
}

Drawing a Finite Automaton

Using the PowerShell DSL/DSV

New-DiGraph {            

    Set-RankDirLR            

    Add-Edge LR_0 LR_2 "SS(B)"
    Add-Edge LR_0 LR_1 "SS(S)"
    Add-Edge LR_1 LR_3 "S(`$end)"
    Add-Edge LR_2 LR_6 "SS(b)"
    Add-Edge LR_2 LR_5 "SS(a)"
    Add-Edge LR_2 LR_4 "S(A)"
    Add-Edge LR_5 LR_7 "S(b)"
    Add-Edge LR_5 LR_5 "S(a)"
    Add-Edge LR_6 LR_6 "S(b)"
    Add-Edge LR_6 LR_5 "S(a)"
    Add-Edge LR_7 LR_8 "S(b)"
    Add-Edge LR_7 LR_5 "S(a)"
    Add-Edge LR_8 LR_6 "S(b)"
    Add-Edge LR_8 LR_5 "S(a)"                

} | Out-Graphviz -dot c:\ps.png -show

The Generated DOT Language

If you do not pipe the New-DiGraph to the Out-Graphviz you get the raw graphviz output. You can save this intermediate step to a file for later use with dot. Save to a file by piping it to | Out-File –Encoding ASCII C:\temp\fsm.gv

digraph test {
 rankdir = LR            

 LR_0 -> LR_2 [ label = "SS(B)" ]
 LR_0 -> LR_1 [ label = "SS(S)" ]
 LR_1 -> LR_3 [ label = "S($end)" ]
 LR_2 -> LR_6 [ label = "SS(b)" ]
 LR_2 -> LR_5 [ label = "SS(a)" ]
 LR_2 -> LR_4 [ label = "S(A)" ]
 LR_5 -> LR_7 [ label = "S(b)" ]
 LR_5 -> LR_5 [ label = "S(a)" ]
 LR_6 -> LR_6 [ label = "S(b)" ]
 LR_6 -> LR_5 [ label = "S(a)" ]
 LR_7 -> LR_8 [ label = "S(b)" ]
 LR_7 -> LR_5 [ label = "S(a)" ]
 LR_8 -> LR_6 [ label = "S(b)" ]
 LR_8 -> LR_5 [ label = "S(a)" ]            

}

View Running Processes on your Box By Company

New-DiGraph {            

    Set-RankDirLR            

    Get-Process |
      Where {$_.Company} |
      ForEach {
          Add-Edge "$($_.Name)" "$($_.Company)"
      }            

} | Out-Graphviz -dot c:\ps.png -show

References

• Graphing with Glee
• PowerShell – Find the K most common words in a file
• Tainted Peanut Butter, The Sequel: PowerShell, DGML and Visual Studio 2010
• PSParser::Tokenize, PowerShell and GLEE

Grab the Code

You need to download the free Graphviz Software here. Then the PowerShell code.

This a great example that leverages many of the different aspects of SQL Server Modeling (”M”-based DSLs, “M”, Modeling Services, etc.) to enable a better experience around application development/management

Here is the MSDN Code Gallery sample RouterManager for WCF in .NET 4 using SQL Server Modeling CTP.

RouterManager is a domain-specific language and runtime that allows you to program the rules for the .NET 4 WCF content-based routing service using an easy to understand language.

You also need Visual Studio 2010 Beta 2 and the SQL Server Modeling CTP.

PowerBoots makes him really really want to move to PowerShell. PowerBoots makes it easy to create GUIs in PowerShell on top of WPF.

Here are some posts on Boots and PowerShell

• JSON, XAML, PowerBoots and PowerShell

• PowerShell, PowerBoots and an Oslo DSL Grammar

• PowerShell Picture Viewer using WPF with PowerBoots

• PowerShell meet WPF via PowerBoots

Intellipad

Working from his example we’ll compile grammar and transform the DSL into Xaml using PowerShell to read and create PS Custom Objects.

• I ‘embedded’ the DSL (lines 1-6)
• The DSL Grammar (lines 9-26)
• Called the M tool chain
  • line 28 the M Compiler
  • line 29 the MGrammar Executor

Then

• Read the Xaml file produced
  • Converted it to an XmlDocument, line 31
  • Looped through the entities in the graph
• And generated PowerShell Custom Objects

Finally

• Using PowerBoots line 38
• The DataGrid from the WPF Toolkit
• Displayed the results

From DSL => DynamicParser => Custom Objects => WPF data bound control

Using the M tool chain in this ways has it’s advantages in several scenarios. This script can easily be streamlined by checking file dates and bypass the m and mgx steps.

In future posts we’ll see if we can interact with the MGrammar namespace and work with Oslo in a deeper way.

Example

The mean return to a portfolio is the weighted average return of the stocks making up the portfolio.

Let’s say a portfolio consists of 30% GOOG shares with a mean daily return of 0.14% and 70% MSFT shares, mean daily return of 0.03%.

The mean daily return is:

(0.3 * .14) + (0.7 * 0.03) = 0.063

Another portfolio of 50% GOOG and 50% MSFT gives

(0.5 * .14) + (0.5 * 0.03) = 0.085

The PowerShell DSV

I’d like to represent the portfolio like the following, legal PowerShell syntax.

Let’s build up the Domain Specific Vocabulary

Lines 1-3 enable the DSV to work and prints:

Adding lines 4-8 will output the snippet below. Note line 7 uses “&”, the PowerShell call operator, to evaluate the script block.

Transform the Data into objects

Let’s transform the data into objects with properties so it prints the following table, with the added plus of addressable properties.

Calculate the Weighted Average

Adding a hash table lookup in lines 4-7 and the properties MeanDailyReturn and WeightedAverage in lines 18-24.

Lines 20 and 23 look up the MeanDailyReturn by stock name using dot notation.

In an upcoming post

The transformation of the DSV into objects and properties is finished. In an upcoming post we’ll add some more detail and play with the output.

A DSL using the "Oslo" toolset that is capable of expressing order generation and responses from a range of market behaviors in terms of FIX messages in a dialect suitable for use by traders and financial engineers

Slide deck HERE, Video HERE

NHModeller is a tool aimed to simplify the development cycle of an NHibernate based application. The engine used to parse the DSL is the Microsoft "Oslo" SDK.

New Oslo CTP

via Chris Sells from TweetDeck

barring any issues with an unrelated MSDN upgrade, we’ll be releasing the #msoslo May CTP on Tues.http://msdn.com/oslo

in action 10-4 Episode 14: Sentient DSLs

Write the code that you think makes sense, and allow the application to create itself. Coding should be fun, and most importantly, it should be easy.

http://www.infoq.com/presentations/Truth-about-DSL

The panelists