Need to rearrange / clean up things. Also there is some duplication on the C# side of it.

If I use build.v4.5.bat I get:

1. Test Error : FSharpx.Tests.ValidationTests.ValidateCustomer
   System.MissingMethodException : Methode nicht gefunden: "Microsoft.FSharp.Cor
   e.FSharpFunc2<System.Collections.Generic.IEnumerable1<System.__Canon>,Microsof
   t.FSharp.Core.FSharpChoice2<Microsoft.FSharp.Collections.FSharpList1<!!1>,Micr
   osoft.FSharp.Collections.FSharpList1<!!2>>> FSharpx.Validation.seqValidator(Mic rosoft.FSharp.Core.FSharpFunc2<System.__Canon,Microsoft.FSharp.Core.FSharpChoic
   e2<!!1,Microsoft.FSharp.Collections.FSharpList1<!!2>>>)".
   bei FSharpx.Tests.ValidationTests.validateOrders[a](IEnumerable`1 c)
   bei FSharpx.Tests.ValidationTests.ValidateCustomer() in .\tests\FSharpx.Tests
   \ValidationTests.fs:Zeile 62.

Hi,

the project should move to https://github.com/fsharp as early as possible.
If this is not possible then we should create our own organization.

Regards,
Steffen

/cc @tpetricek, @mausch, @panesofglass

In XamlTypeprovider.fs : createXamlNode we have

                match wpfAssembly.GetType(sprintf "System.Windows.Controls.%s" other) with
                | null -> typeof<obj>
                | st -> st

As I read (fast) the file, it is therefore only possible to instanciate components from that namespace.
Do you see any obstacle in augmenting this with different components, potentially in other assemblies ?
We'd need to load the dependencies (intercepting System.AppDomain.CurrentDomain.add_AssemblyResolve) , and enhance the XAML parser for getting the namespace.

Since we use the CI server to calculate the release no., we should also configure it to tag the releases back to this repo.

@agross Do you have the public key?

@panesofglass @tpetricek If we have the key can you please give it push privileges to fsharp/fsharpx?

We should create separate nuget packages for every type provider. This will make it easier for users to include just the type providers they need.

I cloned fsharp-fsharpx-74d8db1 and tried to open in Visual Studio 2010 SP1. Neither of the SilverLight projects will open. Visual Studio popup says, "You need to install the latest SilverLight Developer runtime before opening Silverlight project 'FSharpX.Observable.Silverlight''. Download the runtime at http://go.microsoft.com/fwlink/?LinkId=146060" When I follow that link and try to install Silverlight_Developer.exe, it fails, saying "A 64-bit version of Silverlight is already installed".

There is a discussion of this issue here

http://social.msdn.microsoft.com/Forums/en-US/vssetup/thread/eea2a8bf-42c7-46a2-ad4f-664ccab0eb27/

... and the proposed solutions are either (1) uninstall every trace of Silverlight 5 and start over, or (2) install .NET Framework 4.5 beta. I don't want to do either so I'm removing the Silverlight projects from FSharpX.

Has anyone else encountered this issue with FSharpX? If not, do you have .NET Framework 4.5 on your machine?

Hi,

nchrunch can't compile the RoseTreeTests.cs and gives:

RoseTreeTests.cs (13)#0: The name 'LazyListModule' does not exist in the current context
RoseTreeTests.cs (14)#1: The name 'LazyListModule' does not exist in the current context
RoseTreeTests.cs (94)#2: foreach statement cannot operate on variables of type 'Microsoft.FSharp.Collections.LazyList1<FSharpx.DataStructures.RoseTree<T>>' because 'Microsoft.FSharp.Collections.LazyList1<FSharpx.DataStructures.RoseTree>' does not contain a public definition for 'GetEnumerator'

@mausch can you please check this?

If you're on the fsharp-opensource google group you'll see I've been working on improving the landing pages for of open source efforts for F#.

For example, see
http://fsharp.github.com -- the FSharp community on github
http://fsharp.github.com/fsharp -- the FSharp compiler "open source edition"

Would it be OK if I create
http://fsharp.github.com/fsharpx

as a simple landing page for FSharpx? I'd keep it really simple, basing it on the README. Anyone with commit rights on this repo could edit it, and people could submit pull requests against the docs.

Or does someone else want to do this? GitHub has an autodoc generator that can be used.

-- ben

Check that the Regex functions are culture-invariant by default, i.e. when there is no parameter for RegexOptions, RegexOptions.CultureInvariant should be defined by default.
This makes regex functions referentially transparent, just as we did with DateTime.parse et al.

Create a library of FsCheck generators for the provided data structures.

ToFSharpOption is kind of ambiguous. Write tests to expose this, then figure out what to rename.

Every nuget package contains the whole documentation files
this makes the package unnecessary big.
And even worse: it seems we ship the documentation for FSharp.Core and co. ;-)

And make async functions for the rest of the operations.

http://teamcity.codebetter.com/viewType.html?tab=buildTypeStatusDiv&buildTypeId=bt581

Try to analyze the cause.

Follwoing code fails with 'Enumeration has not started. Call MoveNext.' exception:

Option.maybe { for i in [1..10] do () } |> ignore

Change Nullable operators to be like the ones in F# 3.0 http://msdn.microsoft.com/en-us/library/hh323953(v=VS.110).aspx

In order to make the nuget package creation easier, I'll start with a simple merge of the two dll's (putting all the files into the core project).
I'll also delete the F#x.Async package from nuget.org

Later we should do the actual merge. Ok?

"In this version of Visual Studio, F# for Silverlight can only target Silverlight v5.0. Use a prior version of Visual Studio to target previous versions of Silverlight with F#."

Noticed during the F# progressive tutorials that the CSV provider would benefit from a GetCoumn(columnName:string) method that does dynamic lookup by name instead of static binding. This is a normal design pattern for a type provider.

(This was based on using @TomAsp's version of the type provider)

Also GetColumnNames etc. for dynamic access to the schema

Hi @mausch,

I'm getting this error from time to time. Could you please check this? Thanks.

Test cancelled by user
bei System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
bei System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
bei System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
bei NUnit.Core.Reflect.InvokeMethod(MethodInfo method, Object fixture, Object[] args)
bei NUnit.Core.TestMethod.RunTestMethod(TestResult testResult)
bei NUnit.Core.TestMethod.RunTestCase(TestResult testResult)Test cancelled by user
bei System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
bei System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
bei System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
bei NUnit.Core.Reflect.InvokeMethod(MethodInfo method, Object fixture, Object[] args)
bei NUnit.Core.TestMethod.RunTestMethod(TestResult testResult)
bei NUnit.Core.TestMethod.RunTestCase(TestResult testResult)

Timeout of 60000 expired

GetOrElse(null) is currently invalid because it's ambiguous due to the overloads. Consider giving them separate names, like the F# getOrElse/getOrElseF

It used to be
None

it is now

member this.Zero() = Some()

Which means not writing else branch fails if the underlying type is not unit.
So we have to write
else
return! None
Does it make sense to have Some () over None ? I dont see why

The following is from a mail I got via nuget.

"I have run into a compiler warning with a version of this package used in F# WPF Application templates.

It says "Found conflicts between different versions of the same dependent assembly"
I downloaded this program called assembly spy (asmspy.exe) which checks for conflicts, and it turns out there are 5 versions of "FSharpx.TypeProviders" in the package on the NuGet website:
4.0.0.0, 2.0.0.0, 4.3.0.0, 14.0.0.0, 1.6.30.0

I got these references from installing package "1.6.30.0 Thursday, September 13, 2012" directly from the "Package Manager Console" in Visual Studio 2012.

Here is a list of all the references (the app name is "FSTest2": a console application which installs the package and lifts the code and xaml from your "WPFSample" app):

Reference: mscorlib 4.0.0.0 by FSharp.Core 4.0.0.0 by FSharpx.Core 4.0.0.0 by FSharpx.TypeProviders 2.0.0.0 by FSharpx.TypeProviders 4.0.0.0 by FSTest2 Reference: System.Core 4.0.0.0 by FSharp.Core 4.0.0.0 by FSharpx.Core Reference: System 4.0.0.0 by FSharp.Core 4.0.0.0 by FSharpx.Core 4.0.0.0 by FSharpx.TypeProviders Reference: System.Numerics 4.0.0.0 by FSharp.Core Reference: FSharp.Core 4.3.0.0 by FSharpx.Core 4.3.0.0 by FSharpx.TypeProviders 4.3.0.0 by FSTest2 Reference: FSharp.PowerPack 2.0.0.0 by FSharpx.Core Reference: Microsoft.Office.Interop.Excel 14.0.0.0 by FSharpx.TypeProviders Reference: System.Xml 4.0.0.0 by FSharpx.TypeProviders Reference: System.Xml.Linq 4.0.0.0 by FSharpx.TypeProviders Reference: PresentationFramework 4.0.0.0 by FSharpx.TypeProviders 4.0.0.0 by FSTest2 4.0.0.0 by FSTest2 Reference: System.Configuration 4.0.0.0 by FSharpx.TypeProviders Reference: FSharpx.Core 1.6.30.0 by FSharpx.TypeProviders Reference: PresentationCore 4.0.0.0 by FSTest2 Reference: FSharpx.TypeProviders 1.6.30.0 by FSTest2

AsmSpy http://mikehadlow.blogspot.ca/2011/02/asmspy-little-tool-to-help-fix-assembly.html"

When adding a monoid instance for DList:

[<GeneralizableValue>]
let monoid<'a> = 
    { new Monoid<'a DList>() with
        override x.Zero() = empty
        override x.Combine(a,b) = append a b }

It violates the monoid laws:

[<Test>]
let ``dlist monoid``() =
    checkMonoid "dlist" DList.monoid<int>

IReadOnlyCollection: http://msdn.microsoft.com/en-us/library/hh881542.aspx

IReadOnlyList : http://msdn.microsoft.com/en-us/library/hh192385(v=vs.110).aspx

IReadOnlyDictionary: http://msdn.microsoft.com/en-us/library/hh136548(v=vs.110).aspx

ifdef it to ensure they don't get compiled on .NET 4.5.

Adapters to expose:

• F# list as IReadOnlyList
• F# map as IReadOnlyDictionary
• IDictionary as IReadOnlyDictionary
• IList as IReadOnlyList

TryFind for IReadOnlyList and IReadOnlyDictionary

Current NuGet package only includes 4.0 libraries. Build all available target frameworks and include their output in the NuGet package.

Was working on having this auto-generated from FAKE; however, I've been having problems getting FAKE to generate this properly.

We have a lot of cool operators in F#x. Let's try to give them names and add the named vbersions to the prelude (or the monads).

Pull request are welcome on this issue.

I knew there was a bug somewhere in RealTimeQueue for some time, but I never isolated it until I was investigating a "bug" in PhysicistQueue uncons. (I'm pretty sure I isolated it.) The "problem" (I think) in both queues is the use of Lazy<list<'a>> (not to be confused with LazyList<'a>) in critical parts of the types' structures. The result is when a user is recursing over certain operations (uncons and snoc) it eventually results in a stackoverflow. (Something to do with the unforced list must be pushing down on the stack.) And it doesn't matter if you do it in a recursive loop

let rec loop : 'a PhysicistQueue -> unit = function
| PhysicistQueue.Nil -> ()
| PhysicistQueue.Cons(hd, tl) -> loop tl

loop q

(stackoverflow around 8,000 iterations)

or a fold on Seq

let q2 = Seq.fold (fun (q : 'a RealTimeQueue.RealTimeQueue) t -> (RealTimeQueue.snoc t q)) (RealTimeQueue.empty) data

(stackoverflow somewhere between 10,000 and 100,000 iterations)

The Good News: Our original source for these structures apparently made a "copy and paste" bug in RealTimeQueue. It should be a standard list not a suspended list.

But still a problem:

1. Only affects long recursions of Tail, TryGetTail, Uncons, TryUncons in PhysicistQueue.
2. Same Lazy<list<'a>> used in BootstrappedQueue, but for the suspended list, so apparently this doesn't cause a problem.
3. Also used in the segments for BottomUpMergeSort, but I'm guessing you would have to attempt merging thousands of lists for it to be a problem. I haven't tried testing that yet.

I will work on a fix to RealTimeQueue.

Can we have the documentation back in readme.md and just use that file to generate the github pages? It was handy to be able to clone the repository and have that file as part of the tree, it was easier to contribute changes there. Also, having a mix of stuff in the wiki also doesn't help. Would't it be better to have a Readme.md, Build.md, and FSharpx-Async-Extensions.md in the root of FSharpx instead?

After reading http://blog.ctaggart.com/2012/11/parsing-protocol-buffers-proto-file-in-f.html and @dsyme's Mail about the Protocol Buffer (http://code.google.com/p/protobuf/) stuff I think we should add a Protocol Buffer type provider to FSharpx. Since we have type providers for CSV, JSON and XML I think it would fit very nicely.

Here's what I think we have to do:

• Create a Protocol Buffer serializer in FSharpx.Core
• Create a type provider on top of this parser in FSharpx.TypeProviders.Documents

I asked Cameron if he wants to contribute the parser. If he does we need to find a way to deal with the dependency on FParsec.
Alternatively we could write a new parser. Like what we did with the JSON parser.

What do you guys think?

Lenses around DateTime / DateTimeOffset, as in https://github.com/feuerbach/time-lens

See this StackOverflow post.

Add more monoid implementations. From http://www.haskell.org/haskellwiki/Monoid :

• lists under concatenation (done)
• numbers under addition or multiplication
• Booleans under conjunction or disjunction
• sets under union or intersection
• functions from a type to itself, under composition
• Maybe

Now that FAKE supports deploying packages, we should add that to our CI story. It would be really nice to start tightening down our codebase and only push to master when we are really ready to deploy to NuGet.

Hi - I'm trying to use the amazing looking Xaml type provider in a small application. However, I seem unable to install the package via Nuget. It looks to me like the docs are getting installed, but not assemblies (and no references added to my project).

I have tried several times with totally blank F# projects. I do the following:

1. Clear Nuget package cache and restart VS11.
2. Create F# application
3. Change Application Output type to "Windows Application"
4. "install-package FSharpx.TypeProviders" (tried this from console and GUI).
5. Package downloads to packages folder but does not get installed to project (no references or packages.config).
6. If I click "Install" in the GUI it says already installed, but if I look at "Installed Packages" it says "no packages are installed in the current project"

Am I doing something wrong (I'm not a Nuget expert yet)? The Type Providers package has no assemblies in it. Is this correct?

I'm using VS11 - 11.0.50214.1.BETAREL. I have zipped up a project in the state I describe above, and could provide that too if you want. I will continue to try and find the problem, but hope you might tell me where I'm messing up!

Already have a working implementation: https://github.com/mausch/UrchiNet/blob/master/UrchiNet/NonEmptyList.fs

Need to write tests, make it implement seq, write append, collect, fold, etc.

And macke the type provider package a dependency.

@dmohl How can we automatically check if the samples are still valid.

See

• http://www.mail-archive.com/[email protected]/msg23840.html
• http://hackage.haskell.org/packages/archive/partial-lens/0.0.1/doc/html/src/Data-Lens-Partial-Common.html
• scalaz/scalaz@5fe91da
• http://pastebin.com/SJ8FxSkU
• Asymmetric lenses in Scala: http://dl.dropbox.com/u/7810909/media/doc/lenses.pdf

ContinuationSpecs.fs contains a scenario for the callCC operator from the Haskell wiki. I think I implemented callCC correctly since it matches the type signature, but the types don't seem to align as they do in the Haskell example.

I tried to add a portable profile build for the Freebase provider, but I get lot's of errors.
I looked int o the original build from the sample pack:

CCoreCompile:
C:\Program Files (x86)\Microsoft SDKs\F#\3.0\Framework\v4.0\fsc.exe -o:obj\Re
lease\portable47\Samples.DataStore.Freebase.DesignTime.dll --debug:pdbonly --
noframework --define:TYPE_PROVIDER_RUNTIME_FX_PORTABLE47 --define:TRACE --opt
imize+ -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\FSharp\3.0\R
untime\v4.0\FSharp.Core.dll" -r:"C:\Program Files (x86)\Reference Assemblies
Microsoft\Framework.NETFramework\v4.5\mscorlib.dll" -r:"C:\Program Files (x8
6)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.5\System.Core.dl
l" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFr
amework\v4.5\System.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Micr
osoft\Framework.NETFramework\v4.5\System.Net.dll" -r:"C:\Program Files (x86)
\Reference Assemblies\Microsoft\Framework.NETFramework\v4.5\System.Runtime.S
erialization.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\F
ramework.NETFramework\v4.5\System.ServiceModel.Web.dll" -r:"C:\Program Files
(x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.5\System.Web
.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NE
TFramework\v4.5\System.Xml.dll" --target:library --warn:3 --warnaserror:76 --
fullpaths --flaterrors --subsystemversion:6.00 --highentropyva+ /warnon:1182
"C:\Users\Steffen\AppData\Local\Temp.NETFramework,Version=v4.5.AssemblyAttr
ibutes.fs" ..\shared\DefaultVersionAttribute.fs ..\shared\Cache.fsi ..\shared
\Cache.fs ..\shared\JsonParser.fs ..\shared\ProvidedTypes-head.fsi ..\shared
ProvidedTypes-head.fs FreebaseRequests.fs FreebaseSchema.fs FreebaseTypeProvi
der.fs

Why is this using .NET 4.5? And how?

This is what FAKE creates at the moment:

CoreCompile:
C:\Program Files (x86)\Microsoft SDKs\F#\3.0\Framework\v4.0\fsc.exe -o:obj\Release\portable47\FSharpx.TypeProviders.Freebase.dll --debug:pdbonly --noframework --define:NET40 --define:FX_NO_LOCAL_FILESYSTEM --define:FX_NO_CONCURRENT --define:NO_SYSTEM_ENVIRONMENT_GETENVIRONMENTVARIABLE --define:FX_NO_CUSTOMTYPEDESCRIPTOR --define:FX_NO_CUSTOMATTRIBUTEDATA --define:FX_NO_SYNC_WEBRESPONSE --define:FX_NO_WEBREQUEST_CONTENTLENGTH --define:FX_NO_GETCURRENTMETHOD --define:FX_NO_WEBHEADERS_ADD --define:TYPE_PROVIDER_RUNTIME_FX_PORTABLE47 --optimize+ -r:"C:\Program Files (x86)\MSBuild..\Reference Assemblies\Microsoft\FSharp\3.0\Runtime.NETPortable\FSharp.Core.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\mscorlib.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Core.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Net.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Runtime.Serialization.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.ServiceModel.Web.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Xml.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\Microsoft.CSharp.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\mscorlib.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.ComponentModel.DataAnnotations.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Core.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Net.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Numerics.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Runtime.Serialization.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.ServiceModel.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.ServiceModel.Web.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Windows.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Xml.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Xml.Linq.dll" -r:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile47\System.Xml.Serialization.dll" --target:library --warn:3 --warnaserror:76
--fullpaths --flaterrors --highentropyva- /warnon:1182 "C:\Users\Steffen\AppData\Local\Temp.NETPortable,Version=v4.0,Profile=Profile47.AssemblyAttributes.fs"
DefaultVersionAttribute.fs Cache.fsi Cache.fs JsonParser.fs ..\FSharpx.TypeProviders\ProvidedTypes.fsi ..\FSharpx.TypeProviders\ProvidedTypes.fs FreebaseRequests.fs FreebaseSchema.fs FreebaseRuntime.fs

So I think it's referencing the right stuff. But then it fails with:

 1>.\src\FSharpx.TypeProviders\ProvidedTypes.fs(17,24): error FS0039: The namespace 'Emit' is not defined [.\src\FSharpx.TypeProviders.Freebase\FSharpx.TypeProviders.Freebase.fsproj]

If we generate the IL manually, then this should be possible.

Hi,

is anybody using the Silverlight stuff? It's always breaking on my machine.
If not I would remove it. ;-)

Cheers,
Steffen

We should create a list with all datastructures and describe the pros and cons.
It should show time and space complexity for operations, but more importantly give some recommendations for starters.

@jackfoxy can you help?

Mark Pawelek noticed that theCSV provider (actually @tpetricek 's version of it) should by default trim spaces.

This is feedback from the Progressive F# Tutorials in London, using these type providers to create ASP.NET applications

According to docs of Blocking Agent, it should block on get until something is available, and if nothing is then behaviour is undefined.

But docs say that it'll block.

Instead it throws TimeoutException.

I would prefer having Option<_> given, and then returning a None if the timeout expires, because afaik exceptions aren't the quickest way of handling flow control.

I'm using the project here:
https://github.com/mpsbroadband/MassTransit-AzureServiceBus/blob/integration/src/MassTransit.Async/Receiver.fs
https://github.com/mpsbroadband/MassTransit-AzureServiceBus/blob/integration/src/MassTransit.Transports.AzureServiceBus/InboundTransportImpl.cs

if you are interested in seeing it used IRL.

Just as in http://research.microsoft.com/en-us/um/cambridge/projects/fsharp/manual/spec.html#_Toc270597448 (Eventually), move monadic functions out of the computation expressions so they can be used stand-alone.