Filterign koans

.gitignore

@@ -1,9 +1,4 @@
-FSharpKoans.Core/bin/
-FSharpKoans.Core/obj/
-FSharpKoans/bin/
-FSharpKoans/obj/
-FSharpKoans.Test/bin/
-FSharpKoans.Test/obj/
-FSharpKoans2008.suo
-FSharpKoans2010.suo
+[Bb]in/
+[Oo]bj/
+*.suo
 packages/

FSharpKoans.Core/FsharpKoans.Core.fsproj

@@ -14,6 +14,8 @@
     <TargetFrameworkProfile>
     </TargetFrameworkProfile>
     <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\</SolutionDir>
+    <TargetFSharpCoreVersion>4.3.0.0</TargetFSharpCoreVersion>
+    <MinimumVisualStudioVersion Condition="'$(MinimumVisualStudioVersion)' == ''">11</MinimumVisualStudioVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
@@ -34,9 +36,19 @@
     <WarningLevel>3</WarningLevel>
     <DocumentationFile>bin\Release\FSharpKoans.Core.XML</DocumentationFile>
   </PropertyGroup>
-  <Import Project="$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets" Condition="Exists('$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets')" />
-  <Import Project="$(MSBuildExtensionsPath32)\..\Microsoft F#\v4.0\Microsoft.FSharp.Targets" Condition="(!Exists('$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets')) And (Exists('$(MSBuildExtensionsPath32)\..\Microsoft F#\v4.0\Microsoft.FSharp.Targets'))" />
-  <Import Project="$(MSBuildExtensionsPath32)\FSharp\1.0\Microsoft.FSharp.Targets" Condition="(!Exists('$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets')) And (!Exists('$(MSBuildExtensionsPath32)\..\Microsoft F#\v4.0\Microsoft.FSharp.Targets')) And (Exists('$(MSBuildExtensionsPath32)\FSharp\1.0\Microsoft.FSharp.Targets'))" />
+  <Choose>
+    <When Condition="'$(VisualStudioVersion)' == '11.0'">
+      <PropertyGroup>
+        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets</FSharpTargetsPath>
+      </PropertyGroup>
+    </When>
+    <Otherwise>
+      <PropertyGroup>
+        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\FSharp\Microsoft.FSharp.Targets</FSharpTargetsPath>
+      </PropertyGroup>
+    </Otherwise>
+  </Choose>
+  <Import Project="$(FSharpTargetsPath)" Condition="Exists('$(FSharpTargetsPath)')" />
   <ItemGroup>
     <Compile Include="KoanAttribute.fs" />
     <Compile Include="Helpers.fs" />
@@ -46,8 +58,10 @@
     <None Include="packages.config" />
   </ItemGroup>
   <ItemGroup>
+    <Reference Include="FSharp.Core, Version=$(TargetFSharpCoreVersion), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <Private>True</Private>
+    </Reference>
     <Reference Include="mscorlib" />
-    <Reference Include="FSharp.Core" />
     <Reference Include="nunit.framework">
       <HintPath>..\packages\NUnit.2.5.10.11092\lib\nunit.framework.dll</HintPath>
       <Private>True</Private>
@@ -71,4 +85,4 @@
 	<Target Name="AfterBuild">
 	</Target>
 	-->
-</Project>
+</Project>

FSharpKoans.Test/FSharpKoans.Test.fsproj

@@ -12,6 +12,8 @@
     <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
     <Name>FSharpKoans.Test</Name>
     <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\</SolutionDir>
+    <TargetFSharpCoreVersion>4.3.0.0</TargetFSharpCoreVersion>
+    <MinimumVisualStudioVersion Condition="'$(MinimumVisualStudioVersion)' == ''">11</MinimumVisualStudioVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
@@ -32,18 +34,30 @@
     <WarningLevel>3</WarningLevel>
     <DocumentationFile>bin\Release\FSharpKoans.Test.XML</DocumentationFile>
   </PropertyGroup>
-  <Import Project="$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets" Condition="Exists('$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets')" />
-  <Import Project="$(MSBuildExtensionsPath32)\..\Microsoft F#\v4.0\Microsoft.FSharp.Targets" Condition="(!Exists('$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets')) And (Exists('$(MSBuildExtensionsPath32)\..\Microsoft F#\v4.0\Microsoft.FSharp.Targets'))" />
-  <Import Project="$(MSBuildExtensionsPath32)\FSharp\1.0\Microsoft.FSharp.Targets" Condition="(!Exists('$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets')) And (!Exists('$(MSBuildExtensionsPath32)\..\Microsoft F#\v4.0\Microsoft.FSharp.Targets')) And (Exists('$(MSBuildExtensionsPath32)\FSharp\1.0\Microsoft.FSharp.Targets'))" />
+  <Choose>
+    <When Condition="'$(VisualStudioVersion)' == '11.0'">
+      <PropertyGroup>
+        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets</FSharpTargetsPath>
+      </PropertyGroup>
+    </When>
+    <Otherwise>
+      <PropertyGroup>
+        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\FSharp\Microsoft.FSharp.Targets</FSharpTargetsPath>
+      </PropertyGroup>
+    </Otherwise>
+  </Choose>
+  <Import Project="$(FSharpTargetsPath)" Condition="Exists('$(FSharpTargetsPath)')" />
   <ItemGroup>
     <Compile Include="FindingKoans.fs" />
     <Compile Include="RunningKoans.fs" />
     <Compile Include="GettingTheWholeOutput.fs" />
     <None Include="packages.config" />
   </ItemGroup>
   <ItemGroup>
+    <Reference Include="FSharp.Core, Version=$(TargetFSharpCoreVersion), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <Private>True</Private>
+    </Reference>
     <Reference Include="mscorlib" />
-    <Reference Include="FSharp.Core" />
     <Reference Include="nunit.framework">
       <HintPath>..\packages\NUnit.2.5.10.11092\lib\nunit.framework.dll</HintPath>
       <Private>True</Private>
@@ -74,4 +88,4 @@
 	<Target Name="AfterBuild">
 	</Target>
 	-->
-</Project>
+</Project>

FSharpKoans.sln

@@ -1,6 +1,8 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 2012
+# Visual Studio 2013
+VisualStudioVersion = 12.0.31101.0
+MinimumVisualStudioVersion = 10.0.40219.1
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FsharpKoans.Core", "FSharpKoans.Core\FsharpKoans.Core.fsproj", "{71460AA5-7357-4F1C-99BC-54244B50B00E}"
 EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FSharpKoans", "FSharpKoans\FSharpKoans.fsproj", "{87C025E8-3E63-4A20-B1CA-2E346D0E0C51}"
@@ -19,18 +21,6 @@ Global
 		Release|x86 = Release|x86
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|Any CPU.Build.0 = Release|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|Mixed Platforms.Build.0 = Release|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|x64.ActiveCfg = Release|Any CPU
-		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|x86.ActiveCfg = Release|Any CPU
 		{71460AA5-7357-4F1C-99BC-54244B50B00E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{71460AA5-7357-4F1C-99BC-54244B50B00E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{71460AA5-7357-4F1C-99BC-54244B50B00E}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
@@ -55,6 +45,18 @@ Global
 		{87C025E8-3E63-4A20-B1CA-2E346D0E0C51}.Release|x64.ActiveCfg = Release|x86
 		{87C025E8-3E63-4A20-B1CA-2E346D0E0C51}.Release|x86.ActiveCfg = Release|x86
 		{87C025E8-3E63-4A20-B1CA-2E346D0E0C51}.Release|x86.Build.0 = Release|x86
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|Any CPU.Build.0 = Release|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|x64.ActiveCfg = Release|Any CPU
+		{69F00CBF-0EDC-4260-B852-C53B8C44BBCE}.Release|x86.ActiveCfg = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

FSharpKoans/AboutFiltering.fs

@@ -0,0 +1,121 @@
+namespace FSharpKoans
+open FSharpKoans.Core
+
+module NumberFilterer =
+
+    let someIfPositive x =
+        if x % 2 = 0 then Some x
+        else None
+
+//---------------------------------------------------------------
+// Getting Started with Filtering Lists
+//
+// Lists in F# can be filtered in a number of ways. 
+// This koan looks at:
+//  - filter
+//  - find / tryFind
+//  - choose
+//  - pick
+//---------------------------------------------------------------
+
+[<Koan(Sort = 22)>]
+module ``about filtering`` =
+    open NumberFilterer
+
+    [<Koan>]
+    let FilteringAList() =
+        let names = [ "Alice"; "Bob"; "Eve"; ]
+
+        // Find all the names starting with "A" using an anonymous function
+        let actual_names = 
+            names
+            |> List.filter (fun name -> name.StartsWith( "A" ))
+
+        AssertEquality actual_names [ __ ]
+
+        //Or passing a function to filter
+        let startsWithTheLetterB (s: string) =
+            s.StartsWith("B")
+
+        let namesBeginningWithB =
+            names
+            |> List.filter startsWithTheLetterB
+
+        AssertEquality namesBeginningWithB [ __ ]
+
+    [<Koan>]
+    let FindingJustOneItem() =
+        let names = [ "Alice"; "Bob"; "Eve"; ]
+        let expected_name = "Bob"
+
+        // find will return just one item, or throws an exception
+
+        let actual_name = 
+            names
+            |> List.find (fun name -> name = __ )
+
+        //??? What would happen if there are 2 Bob's in the List?
+
+        AssertEquality expected_name actual_name
+
+    [<Koan>]
+    let FindingJustOneOrZeroItem() =
+        let names = [ "Alice"; "Bob"; "Eve"; ]
+
+        // tryFind returns an option so you can handle 0 rows returned
+        let eve = 
+            names
+            |> List.tryFind (fun name -> name = "Eve" )
+        let zelda = 
+            names
+            |> List.tryFind (fun name -> name = "Zelda" )
+
+        AssertEquality eve.IsSome __
+        AssertEquality zelda.IsSome __
+
+    [<Koan>]
+    let ChoosingItemsFromAList() =
+        let numbers = [ 1; 2; 3; ]
+
+        // choose takes a function that transforms the input into an option
+        // And filters out the results that are None.
+        let positiveNumbers =
+            numbers
+            |> List.choose someIfPositive
+
+        AssertEquality positiveNumbers  [ __ ]
+
+        //You can also use the "id" function on types of 'a option list 
+        //"id" will tell choose only to return just those that are "Some"
+        let optionNames = [ None; Some "Alice"; None; ]
+
+        let namesWithValue = 
+            optionNames
+            |> List.choose id
+
+        //Notice the type of actual result is 'string list', where as optionNumbers is 'string option list'
+        AssertEquality namesWithValue [ __ ]
+
+    [<Koan>]
+    let PickingItemsFromAList() =
+        let numbers = [ 5..10 ]
+
+        //Pick is similar to choose, but returns the first element, or throwns an exception if are no
+        //items that return "Some" (a bit like find does)
+        let firstEvenPositive =
+            numbers
+            |> List.pick someIfPositive
+
+        AssertEquality firstEvenPositive __
+
+        //As with choose, you can also use the "id" function on types of 'a option list 
+        //to return just those that are "Some"
+        let optionNames = [ None; Some "Alice"; None; Some "Bob"; ]
+
+        let firstNameWithValue = 
+            optionNames
+            |> List.pick id
+
+        AssertEquality firstNameWithValue  __
+
+        //There is also a tryPick which works like tryFind, returning "None" instead of throwing an exception.

FSharpKoans/FSharpKoans.fsproj

@@ -14,6 +14,8 @@
     </TargetFrameworkProfile>
     <Name>FSharpKoans</Name>
     <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\</SolutionDir>
+    <TargetFSharpCoreVersion>4.3.0.0</TargetFSharpCoreVersion>
+    <MinimumVisualStudioVersion Condition="'$(MinimumVisualStudioVersion)' == ''">11</MinimumVisualStudioVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|x86' ">
     <DebugSymbols>true</DebugSymbols>
@@ -37,9 +39,19 @@
     <PlatformTarget>x86</PlatformTarget>
     <DocumentationFile>bin\Release\FSharpKoans1.XML</DocumentationFile>
   </PropertyGroup>
-  <Import Project="$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets" Condition="Exists('$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets')" />
-  <Import Project="$(MSBuildExtensionsPath32)\..\Microsoft F#\v4.0\Microsoft.FSharp.Targets" Condition="(!Exists('$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets')) And (Exists('$(MSBuildExtensionsPath32)\..\Microsoft F#\v4.0\Microsoft.FSharp.Targets'))" />
-  <Import Project="$(MSBuildExtensionsPath32)\FSharp\1.0\Microsoft.FSharp.Targets" Condition="(!Exists('$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets')) And (!Exists('$(MSBuildExtensionsPath32)\..\Microsoft F#\v4.0\Microsoft.FSharp.Targets')) And (Exists('$(MSBuildExtensionsPath32)\FSharp\1.0\Microsoft.FSharp.Targets'))" />
+  <Choose>
+    <When Condition="'$(VisualStudioVersion)' == '11.0'">
+      <PropertyGroup>
+        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets</FSharpTargetsPath>
+      </PropertyGroup>
+    </When>
+    <Otherwise>
+      <PropertyGroup>
+        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\FSharp\Microsoft.FSharp.Targets</FSharpTargetsPath>
+      </PropertyGroup>
+    </Otherwise>
+  </Choose>
+  <Import Project="$(FSharpTargetsPath)" Condition="Exists('$(FSharpTargetsPath)')" />
   <PropertyGroup>
     <PreBuildEvent />
   </PropertyGroup>
@@ -64,14 +76,17 @@
     <Compile Include="AboutDiscriminatedUnions.fs" />
     <Compile Include="AboutModules.fs" />
     <Compile Include="AboutClasses.fs" />
+    <Compile Include="AboutFiltering.fs" />
     <Compile Include="PathToEnlightenment.fs" />
     <None Include="App.config">
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>
     </None>
   </ItemGroup>
   <ItemGroup>
+    <Reference Include="FSharp.Core, Version=$(TargetFSharpCoreVersion), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <Private>True</Private>
+    </Reference>
     <Reference Include="mscorlib" />
-    <Reference Include="FSharp.Core" />
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.Numerics" />