Merge pull request #531 from zspitz/main

Some dotnet script improvements; Animal (VB.NET)

00_Utilities/DotnetUtils/DotnetUtils/Extensions.cs

@@ -10,6 +10,11 @@ public static class Extensions {
         src.Select(x => selector(x.Item1, x.Item2, x.Item3));
     public static IEnumerable<(T1, T2, int)> WithIndex<T1, T2>(this IEnumerable<(T1, T2)> src) => src.Select((x, index) => (x.Item1, x.Item2, index));
 
+    public static bool None<T>(this IEnumerable<T> src, Func<T, bool>? predicate = null) =>
+        predicate is null ?
+            !src.Any() :
+            !src.Any(predicate);
+
     public static bool IsNullOrWhitespace([NotNullWhen(false)] this string? s) => string.IsNullOrWhiteSpace(s);
 
     [return: NotNullIfNotNull("path")]

00_Utilities/DotnetUtils/DotnetUtils/Program.cs

@@ -17,6 +17,7 @@ var actions = new (Action action, string description)[] {
     (multipleProjs, "Output multiple project files"),
     (checkProjects, "Check .csproj/.vbproj files for target framework, nullability etc."),
     (checkExecutableProject, "Check that there is at least one executable project per port"),
+    (noCodeFiles, "Output ports without any code files"),
     (printPortInfo, "Print info about a single port"),
 
     (generateMissingSlns, "Generate solution files when missing"),
@@ -87,7 +88,7 @@ void printInfos() {
 }
 
 void missingSln() {
-    var data = infos.Where(x => !x.Slns.Any()).ToArray();
+    var data = infos.Where(x => x.Slns.None()).ToArray();
     foreach (var item in data) {
         WriteLine(item.LangPath);
     }
@@ -98,7 +99,7 @@ void missingSln() {
 void unexpectedSlnName() {
     var counter = 0;
     foreach (var item in infos) {
-        if (!item.Slns.Any()) { continue; }
+        if (item.Slns.None()) { continue; }
 
         var expectedSlnName = $"{item.GameName}.sln";
         if (item.Slns.Contains(Combine(item.LangPath, expectedSlnName), StringComparer.InvariantCultureIgnoreCase)) { continue; }
@@ -125,7 +126,7 @@ void multipleSlns() {
 }
 
 void missingProj() {
-    var data = infos.Where(x => !x.Projs.Any()).ToArray();
+    var data = infos.Where(x => x.Projs.None()).ToArray();
     foreach (var item in data) {
         WriteLine(item.LangPath);
     }
@@ -136,7 +137,7 @@ void missingProj() {
 void unexpectedProjName() {
     var counter = 0;
     foreach (var item in infos) {
-        if (!item.Projs.Any()) { continue; }
+        if (item.Projs.None()) { continue; }
 
         var expectedProjName = $"{item.GameName}.{item.ProjExt}";
         if (item.Projs.Contains(Combine(item.LangPath, expectedProjName))) { continue; }
@@ -164,7 +165,7 @@ void multipleProjs() {
 }
 
 void generateMissingSlns() {
-    foreach (var item in infos.Where(x => !x.Slns.Any())) {
+    foreach (var item in infos.Where(x => x.Slns.None())) {
         var result = RunProcess("dotnet", $"new sln -n {item.GameName} -o {item.LangPath}");
         WriteLine(result);
 
@@ -177,7 +178,7 @@ void generateMissingSlns() {
 }
 
 void generateMissingProjs() {
-    foreach (var item in infos.Where(x => !x.Projs.Any())) {
+    foreach (var item in infos.Where(x => x.Projs.None())) {
         // We can't use the dotnet command to create a new project using the built-in console template, because part of that template
         // is a Program.cs / Program.vb file. If there already are code files, there's no need to add a new empty one; and 
         // if there's already such a file, it might try to overwrite it.
@@ -216,8 +217,8 @@ void generateMissingProjs() {
 
 void checkProjects() {
     foreach (var info in infos) {
+        WriteLine(info.LangPath);
         printProjectWarnings(info);
-        WriteLine();
     }
 }
 
@@ -231,13 +232,15 @@ void printProjectWarnings(PortInfo info) {
             nullable,
             implicitUsing,
             rootNamespace,
-            langVersion
+            langVersion,
+            optionStrict
         ) = (
             getValue(parent, "TargetFramework", "TargetFrameworks"),
             getValue(parent, "Nullable"),
             getValue(parent, "ImplicitUsings"),
             getValue(parent, "RootNamespace"),
-            getValue(parent, "LangVersion")
+            getValue(parent, "LangVersion"),
+            getValue(parent, "OptionStrict")
         );
 
         if (framework != "net6.0") {
@@ -266,6 +269,9 @@ void printProjectWarnings(PortInfo info) {
             if (langVersion != "16.9") {
                 warnings.Add($"LangVersion: {langVersion}");
             }
+            if (optionStrict != "On") {
+                warnings.Add($"OptionStrict: {optionStrict}");
+            }
         }
 
         if (warnings.Any()) {
@@ -284,6 +290,15 @@ void checkExecutableProject() {
     }
 }
 
+void noCodeFiles() {
+    var qry = infos
+        .Where(x => x.CodeFiles.None())
+        .OrderBy(x => x.Lang);
+    foreach (var item in qry) {
+        WriteLine(item.LangPath);
+    }
+}
+
 void tryBuild() {
     // if has code files, try to build
 }

03_Animal/vbnet/Animal.Tests/Animal.Tests.vbproj

@@ -0,0 +1,27 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <RootNamespace>Animal.Tests</RootNamespace>
+    <TargetFramework>net6.0</TargetFramework>
+    <IsPackable>false</IsPackable>
+    <OptionStrict>On</OptionStrict>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
+    <PackageReference Include="xunit" Version="2.4.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="coverlet.collector" Version="3.1.0">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Animal\Animal.vbproj" />
+  </ItemGroup>
+
+</Project>

03_Animal/vbnet/Animal.Tests/MockConsole.vb

@@ -0,0 +1,65 @@
+Imports System.IO
+
+Public Class MockConsole
+    Inherits ConsoleAdapterBase
+
+    Private inputs As Queue(Of String)
+    Public ReadOnly Lines As New List(Of (line As String, centered As Boolean)) From {
+        ("", False)
+    }
+
+    ' TODO it's possible to clear all the lines, and we'd have to check once again in WriteString and WriteCenteredLine if there are any lines
+
+    Sub New(Inputs As IEnumerable(Of String))
+        Me.inputs = New Queue(Of String)(Inputs)
+    End Sub
+
+    Private Sub CheckLinesInitialized()
+        If Lines.Count = 0 Then Lines.Add(("", False))
+    End Sub
+
+    Private Sub WriteString(s As String, Optional centered As Boolean = False)
+        If s Is Nothing Then Return
+        CheckLinesInitialized()
+        s.Split(Environment.NewLine).ForEach(Sub(line, index)
+                                                 If index = 0 Then
+                                                     Dim currentLast = Lines(Lines.Count - 1)
+                                                     ' centered should never come from the current last line
+                                                     ' if WriteCenteredLine is called, it immediately creates a new line
+                                                     Lines(Lines.Count - 1) = (currentLast.line + line, centered)
+                                                 Else
+                                                     Lines.Add((line, centered))
+                                                 End If
+                                             End Sub)
+    End Sub
+
+    Public Overrides Sub Write(value As Object)
+        WriteString(value?.ToString)
+    End Sub
+
+    Public Overrides Sub WriteLine(value As Object)
+        WriteString(value?.ToString)
+        WriteLine()
+    End Sub
+
+    Public Overrides Sub WriteLine()
+        Lines.Add(("", False))
+    End Sub
+
+    Public Overrides Sub WriteCenteredLine(value As Object)
+        If Lines.Count = 0 Then Lines.Add(("", False))
+        Dim currentLast = Lines(Lines.Count - 1).line
+        If currentLast.Length > 0 Then Throw New InvalidOperationException("Can only write centered line if cursor is at start of line.")
+        WriteString(value?.ToString, True)
+        WriteLine()
+    End Sub
+
+    Public Overrides Function ReadLine() As String
+        ' Indicates the end of a test run, for programs which loop endlessly
+        If inputs.Count = 0 Then Throw New EndOfStreamException("End of inputs")
+
+        Dim nextInput = inputs.Dequeue.Trim
+        WriteLine(nextInput)
+        Return nextInput
+    End Function
+End Class

03_Animal/vbnet/Animal.Tests/TestContainer.vb

@@ -0,0 +1,80 @@
+Imports Xunit
+Imports Animal
+Imports System.IO
+
+Public Class TestContainer
+    Private Shared Function ResponseVariantExpander(src As IEnumerable(Of String)) As TheoryData(Of String)
+        Dim theoryData = New TheoryData(Of String)
+        src.
+            SelectMany(Function(x) {x, x.Substring(0, 1)}).
+            SelectMany(Function(x) {
+                x,
+                x.ToUpperInvariant,
+                x.ToLowerInvariant,
+                x.ToTitleCase,
+                x.ToReverseCase
+            }).
+            Distinct.
+            ForEach(Sub(x) theoryData.Add(x))
+        Return theoryData
+    End Function
+    Private Shared YesVariantsThepryData As TheoryData(Of String) = ResponseVariantExpander({"yes", "true", "1"})
+    Private Shared Function YesVariants() As TheoryData(Of String)
+        Return YesVariantsThepryData
+    End Function
+    Private Shared NoVariantsThepryData As TheoryData(Of String) = ResponseVariantExpander({"no", "false", "0"})
+    Private Shared Function NoVariants() As TheoryData(Of String)
+        Return NoVariantsThepryData
+    End Function
+
+    ''' <summary>Test LIST variants</summary>
+    <Theory>
+    <InlineData("LIST")>
+    <InlineData("list")>
+    <InlineData("List")>
+    <InlineData("lIST")>
+    Sub List(listResponse As String)
+        Dim console As New MockConsole({listResponse})
+        Dim game As New Game(console)
+        Assert.Throws(Of EndOfStreamException)(Sub() game.BeginLoop())
+        Assert.Equal(
+            {
+                "ANIMALS I ALREADY KNOW ARE:",
+                "FISH           BIRD           "
+            },
+            console.Lines.Slice(-4, -2).Select(Function(x) x.line)
+        )
+    End Sub
+
+    '' <summary>Test YES variants</summary>
+    <Theory>
+    <MemberData(NameOf(YesVariants))>
+    Sub YesVariant(yesVariant As String)
+        Dim console As New MockConsole({yesVariant})
+        Dim game As New Game(console)
+        Assert.Throws(Of EndOfStreamException)(Sub() game.BeginLoop())
+        Assert.Equal(
+            {
+                $"ARE YOU THINKING OF AN ANIMAL? {yesVariant}",
+                "DOES IT SWIM? "
+            },
+            console.Lines.Slice(-2, 0).Select(Function(x) x.line)
+        )
+    End Sub
+
+    '' <summary>Test NO variants</summary>
+    <Theory>
+    <MemberData(NameOf(NoVariants))>
+    Sub NoVariant(noVariant As String)
+        Dim console As New MockConsole({"y", noVariant})
+        Dim game As New Game(console)
+        Assert.Throws(Of EndOfStreamException)(Sub() game.BeginLoop())
+        Assert.Equal(
+            {
+                $"DOES IT SWIM? {noVariant}",
+                "IS IT A BIRD? "
+            },
+            console.Lines.Slice(-2, 0).Select(Function(x) x.line)
+        )
+    End Sub
+End Class

03_Animal/vbnet/Animal.sln

@@ -1,22 +1,31 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
+# Visual Studio Version 17
-VisualStudioVersion = 16.0.30114.105
+VisualStudioVersion = 17.0.32112.339
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{F184B08F-C81C-45F6-A57F-5ABD9991F28F}") = "Animal", "Animal.vbproj", "{147D66D5-D817-4024-9447-9F5B9A6D2B7D}"
+Project("{778DAE3C-4631-46EA-AA77-85C1314464D9}") = "Animal", "Animal\Animal.vbproj", "{5517E4CE-BCF9-4D1F-9A17-B620C1B96B0D}"
+EndProject
+Project("{F184B08F-C81C-45F6-A57F-5ABD9991F28F}") = "Animal.Tests", "Animal.Tests\Animal.Tests.vbproj", "{3986C6A2-77D4-4F00-B3CF-F5736C623B1E}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
 		Release|Any CPU = Release|Any CPU
 	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{5517E4CE-BCF9-4D1F-9A17-B620C1B96B0D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{5517E4CE-BCF9-4D1F-9A17-B620C1B96B0D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{5517E4CE-BCF9-4D1F-9A17-B620C1B96B0D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{5517E4CE-BCF9-4D1F-9A17-B620C1B96B0D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{3986C6A2-77D4-4F00-B3CF-F5736C623B1E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{3986C6A2-77D4-4F00-B3CF-F5736C623B1E}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3986C6A2-77D4-4F00-B3CF-F5736C623B1E}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{3986C6A2-77D4-4F00-B3CF-F5736C623B1E}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+	GlobalSection(ExtensibilityGlobals) = postSolution
-		{147D66D5-D817-4024-9447-9F5B9A6D2B7D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		SolutionGuid = {88469A47-E30C-4763-A325-074101D16608}
-		{147D66D5-D817-4024-9447-9F5B9A6D2B7D}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{147D66D5-D817-4024-9447-9F5B9A6D2B7D}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{147D66D5-D817-4024-9447-9F5B9A6D2B7D}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 EndGlobal

03_Animal/vbnet/Animal/Animal.vbproj

@@ -4,5 +4,6 @@
     <RootNamespace>Animal</RootNamespace>
     <TargetFramework>net6.0</TargetFramework>
     <LangVersion>16.9</LangVersion>
+    <OptionStrict>On</OptionStrict>
   </PropertyGroup>
 </Project>

03_Animal/vbnet/Animal/Branch.vb

@@ -0,0 +1,29 @@
+Public Class Branch
+    Public Property Text As String
+
+    Public ReadOnly Property IsEnd As Boolean
+        Get
+            Return Yes Is Nothing AndAlso No Is Nothing
+        End Get
+    End Property
+
+    Public Property Yes As Branch
+    Public Property No As Branch
+
+    ' Allows walking all the descendants recursively
+    Public Iterator Function DescendantTexts() As IEnumerable(Of String)
+        If Yes IsNot Nothing Then
+            Yield Yes.Text
+            For Each childText In Yes.DescendantTexts
+                Yield childText
+            Next
+        End If
+
+        If No IsNot Nothing Then
+            Yield No.Text
+            For Each childText In No.DescendantTexts
+                Yield childText
+            Next
+        End If
+    End Function
+End Class

03_Animal/vbnet/Animal/Game.vb

@@ -0,0 +1,152 @@
+Option Compare Text
+
+Public Class Game
+    ' This Dictionary holds the corresponding value for each of the variants of "YES" and "NO" we accept
+    ' Note that the Dictionary is case-insensitive, meaning it maps "YES", "yes" and even "yEs" to True
+    Private Shared ReadOnly YesNoResponses As New Dictionary(Of String, Boolean)(StringComparer.InvariantCultureIgnoreCase) From {
+        {"yes", True},
+        {"y", True},
+        {"true", True},
+        {"t", True},
+        {"1", True},
+        {"no", False},
+        {"n", False},
+        {"false", False},
+        {"f", False},
+        {"0", False}
+    }
+
+    ReadOnly console As ConsoleAdapterBase
+
+    ' The pre-initialized root branch
+    ReadOnly root As New Branch With {
+        .Text = "DOES IT SWIM?",
+        .Yes = New Branch With {.Text = "FISH"},
+        .No = New Branch With {.Text = "BIRD"}
+    }
+
+    ''' <summary>Reduces a string or console input to True, False or Nothing. Case-insensitive.</summary>
+    ''' <param name="s">Optional String to reduce via the same logic. If not passed in, will use console.ReadLine</param>
+    ''' <returns>
+    ''' Returns True for a "yes" response (yes, y, true, t, 1) and False for a "no" response (no, n, false, f, 0).<br/>
+    ''' Returns Nothing if the response doesn't match any of these.
+    ''' </returns>
+    Private Function GetYesNo(Optional s As String = Nothing) As Boolean?
+        s = If(s, console.ReadLine)
+        Dim ret As Boolean
+        If YesNoResponses.TryGetValue(s, ret) Then Return ret
+        Return Nothing
+    End Function
+
+    Sub New(console As ConsoleAdapterBase)
+        If console Is Nothing Then Throw New ArgumentNullException(NameOf(console))
+        Me.console = console
+    End Sub
+
+
+    Sub BeginLoop()
+        ' Print the program heading
+        console.WriteCenteredLine("ANIMAL")
+        console.WriteCenteredLine("CREATIVE COMPUTING  MORRISTOWN, NEW JERSEY")
+        console.Write(
+"
+
+
+PLAY 'GUESS THE ANIMAL'
+
+THINK OF AN ANIMAL AND THE COMPUTER WILL TRY TO GUESS IT.
+
+")
+
+        Do
+            console.Write("ARE YOU THINKING OF AN ANIMAL? ")
+
+            Dim response = console.ReadLine
+            If response = "list" Then
+                ' List all the stored animals
+                console.WriteLine(
+"
+ANIMALS I ALREADY KNOW ARE:")
+
+                ' We're using a ForEach extension method instead of the regular For Each loop to provide the index alongside the text
+                root.DescendantTexts.ForEach(Sub(text, index)
+                                                 ' We want to move to the next line after every four animals
+                                                 ' But for the first animal, where the index is 0, 0 Mod 4 will also return 0
+                                                 ' So we have to explicitly exclude the first animal
+                                                 If index > 0 AndAlso index Mod 4 = 0 Then console.WriteLine()
+                                                 console.Write($"{text.MaxLength(15),-15}")
+                                             End Sub)
+                console.WriteLine(
+"
+")
+                Continue Do
+            End If
+
+            Dim ynResponse = GetYesNo(response)
+            If ynResponse Is Nothing OrElse Not ynResponse Then Continue Do
+
+            Dim currentBranch = root
+            Do While Not currentBranch.IsEnd
+                ' Branches can either be questions, or end branches
+                ' We have to walk the questions, prompting each time for "yes" or "no"
+                console.Write($"{currentBranch.Text} ")
+                Do
+                    ynResponse = GetYesNo()
+                Loop While ynResponse Is Nothing
+
+                ' Depending on the answer, we'll follow either the branch at "Yes" or "No"
+                currentBranch = If(
+                    ynResponse,
+                    currentBranch.Yes,
+                    currentBranch.No
+                )
+            Loop
+
+            ' Now we're at an end branch
+            console.Write($"IS IT A {currentBranch.Text}? ")
+            ynResponse = GetYesNo()
+            If ynResponse Then ' Only if ynResponse = True will we go into this If Then
+                console.WriteLine("WHY NOT TRY ANOTHER ANIMAL?")
+                Continue Do
+            End If
+
+            ' Get the new animal
+            console.Write("THE ANIMAL YOU WERE THINKING OF WAS A ? ")
+            Dim newAnimal = console.ReadLine
+
+            ' Get the question used to distinguish the new animal from the current end branch
+            console.WriteLine(
+$"PLEASE TYPE IN A QUESTION THAT WOULD DISTINGUISH A 
+{newAnimal} FROM A {currentBranch.Text}")
+            Dim newQuestion = console.ReadLine
+
+            ' Get the answer to that question, for the new animal
+            ' for the old animal, the answer would be the opposite
+            console.Write(
+$"FOR A {newAnimal} THE ANSWER WOULD BE ? ")
+            Do
+                ynResponse = GetYesNo()
+            Loop While ynResponse Is Nothing
+
+            ' Create the new end branch for the new animal
+            Dim newBranch = New Branch With {.Text = newAnimal}
+
+            ' Copy over the current animal to another new end branch
+            Dim currentBranchCopy = New Branch With {.Text = currentBranch.Text}
+
+            ' Make the current branch into the distinguishing question
+            currentBranch.Text = newQuestion
+
+            ' Set the Yes and No branches of the current branch according to the answer
+            If ynResponse Then
+                currentBranch.Yes = newBranch
+                currentBranch.No = currentBranchCopy
+            Else
+                currentBranch.No = newBranch
+                currentBranch.Yes = currentBranchCopy
+            End If
+
+            ' TODO how do we exit?
+        Loop
+    End Sub
+End Class

03_Animal/vbnet/Animal/Program.vb

@@ -0,0 +1,6 @@
+Module Program
+    Sub Main()
+        Dim game As New Game(New ConsoleAdapter)
+        game.BeginLoop()
+    End Sub
+End Module

03_Animal/vbnet/Animal/Shared/ConsoleAdapter.vb

@@ -0,0 +1,29 @@
+Public Class ConsoleAdapter
+    Inherits ConsoleAdapterBase
+
+    Public Overrides Sub Write(value As Object)
+        Console.Write(value)
+    End Sub
+
+    Public Overrides Sub WriteLine(value As Object)
+        Console.WriteLine(value)
+    End Sub
+
+    Public Overrides Sub WriteLine()
+        Console.WriteLine()
+    End Sub
+
+    Public Overrides Sub WriteCenteredLine(value As Object)
+        If Console.CursorLeft <> 0 Then Throw New InvalidOperationException("Can only write centered line if cursor is at start of line.")
+        Dim toWrite = If(value?.ToString, "")
+        Console.WriteLine($"{Space((Console.WindowWidth - toWrite.Length) \ 2)}{toWrite}")
+    End Sub
+
+    Public Overrides Function ReadLine() As String
+        Dim response As String
+        Do
+            response = Console.ReadLine
+        Loop While response Is Nothing
+        Return response.Trim
+    End Function
+End Class

03_Animal/vbnet/Animal/Shared/ConsoleAdapterBase.vb

@@ -0,0 +1,9 @@
+Public MustInherit Class ConsoleAdapterBase
+    Public MustOverride Sub Write(value As Object)
+    Public MustOverride Sub WriteLine(value As Object)
+    Public MustOverride Sub WriteLine()
+    Public MustOverride Sub WriteCenteredLine(value As Object)
+
+    ''' <summary>Implementations should always return a String without leading or trailing whitespace, never Nothng</summary>
+    Public MustOverride Function ReadLine() As String
+End Class

03_Animal/vbnet/Animal/Shared/Extensions.vb

@@ -0,0 +1,50 @@
+Imports System.Runtime.CompilerServices
+
+Public Module Extensions
+    <Extension> Public Sub ForEach(Of T)(src As IEnumerable(Of T), action As Action(Of T))
+        For Each x In src
+            action(x)
+        Next
+    End Sub
+    <Extension> Public Sub ForEach(Of T)(src As IEnumerable(Of T), action As Action(Of T, Integer))
+        Dim index As Integer
+        For Each x In src
+            action(x, index)
+            index += 1
+        Next
+    End Sub
+
+    <Extension> Public Function MaxLength(s As String, value As Integer) As String
+        If s Is Nothing Then Return Nothing
+        Return s.Substring(0, Math.Min(s.Length, value))
+    End Function
+
+    <Extension> Public Function ForceEndsWith(s As String, toAppend As String) As String
+        If Not s.EndsWith(toAppend, StringComparison.OrdinalIgnoreCase) Then s += toAppend
+        Return s
+    End Function
+
+    <Extension> Public Function ToTitleCase(s As String) As String
+        If s Is Nothing Then Return Nothing
+        Return Char.ToUpperInvariant(s(0)) + s.Substring(1).ToUpperInvariant
+    End Function
+
+    ' https://stackoverflow.com/a/3681580/111794
+    <Extension> Public Function ToReverseCase(s As String) As String
+        If s Is Nothing Then Return Nothing
+        Return New String(s.Select(Function(c) If(
+            Not Char.IsLetter(c),
+            c,
+            If(
+                Char.IsUpper(c), Char.ToLowerInvariant(c), Char.ToUpperInvariant(c)
+            )
+            )).ToArray)
+    End Function
+
+    ' https://stackoverflow.com/a/58132204/111794
+    <Extension> Public Function Slice(Of T)(lst As IList(Of T), start As Integer, [end] As Integer) As T()
+        start = If(start >= 0, start, lst.Count + start)
+        [end] = If([end] > 0, [end], lst.Count + [end])
+        Return lst.Skip(start).Take([end] - start).ToArray
+    End Function
+End Module

05_Bagels/csharp/Bagels.csproj

@@ -3,7 +3,6 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net5.0</TargetFramework>
-    <RootNamespace>BasicComputerGames.Bagels</RootNamespace>
   </PropertyGroup>
 
   <ItemGroup>

06_Banner/vbnet/banner.vbproj

@@ -2,8 +2,9 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <RootNamespace>banner</RootNamespace>
+    <RootNamespace>Banner</RootNamespace>
     <TargetFramework>netcoreapp3.1</TargetFramework>
+    <LangVersion>16.9</LangVersion>
   </PropertyGroup>
 
 </Project>

08_Batnum/vbnet/batnum.vbproj

@@ -2,8 +2,9 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <RootNamespace>batnum</RootNamespace>
+    <RootNamespace>Batnum</RootNamespace>
     <TargetFramework>netcoreapp3.1</TargetFramework>
+    <LangVersion>16.9</LangVersion>
   </PropertyGroup>
 
 </Project>

21_Calendar/csharp/Calendar.csproj

@@ -3,7 +3,6 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net5.0</TargetFramework>
-    <RootNamespace>_21_calendar</RootNamespace>
   </PropertyGroup>
 
 </Project>

96_Word/vbnet/word.vbproj

@@ -2,8 +2,9 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <RootNamespace>word</RootNamespace>
+    <RootNamespace>Word</RootNamespace>
     <TargetFramework>netcoreapp3.1</TargetFramework>
+    <LangVersion>16.9</LangVersion>
   </PropertyGroup>
 
 </Project>