Add strain

config.json

@@ -673,6 +673,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "strain",
+        "name": "Strain",
+        "uuid": "cb9e7d32-db32-4de7-a588-940a3551d24f",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "sum-of-multiples",
         "name": "Sum of Multiples",

exercises/Exercises.slnx

@@ -97,6 +97,7 @@
     <Project Path="practice/spiral-matrix/SpiralMatrix.vbproj" />
     <Project Path="practice/square-root/SquareRoot.vbproj" />
     <Project Path="practice/sublist/Sublist.vbproj" />
+    <Project Path="practice/strain/Strain.vbproj" />
     <Project Path="practice/sum-of-multiples/SumOfMultiples.vbproj" />
     <Project Path="practice/tournament/Tournament.vbproj" />
     <Project Path="practice/transpose/Transpose.vbproj" />

exercises/practice/strain/.docs/instructions.md

@@ -0,0 +1,29 @@
+# Instructions
+
+Implement the `keep` and `discard` operation on collections.
+Given a collection and a predicate on the collection's elements, `keep` returns a new collection containing those elements where the predicate is true, while `discard` returns a new collection containing those elements where the predicate is false.
+
+For example, given the collection of numbers:
+
+- 1, 2, 3, 4, 5
+
+And the predicate:
+
+- is the number even?
+
+Then your keep operation should produce:
+
+- 2, 4
+
+While your discard operation should produce:
+
+- 1, 3, 5
+
+Note that the union of keep and discard is all the elements.
+
+The functions may be called `keep` and `discard`, or they may need different names in order to not clash with existing functions or concepts in your language.
+
+## Restrictions
+
+Keep your hands off that filter/reject/whatchamacallit functionality provided by your standard library!
+Solve this one yourself using other basic tools instead.

exercises/practice/strain/.editorconfig

@@ -0,0 +1,89 @@
+###############################
+# Core EditorConfig Options   #
+###############################
+
+; This file is for unifying the coding style for different editors and IDEs.
+; More information at:
+; https://docs.microsoft.com/en-us/visualstudio/ide/editorconfig-code-style-settings-reference?view=vs-2022
+; https://docs.microsoft.com/en-us/visualstudio/ide/create-portable-custom-editor-options?view=vs-2022
+
+root = true
+
+[*]
+end_of_line = lf
+indent_style = space
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.{vbproj,slnx}]
+indent_size = 2
+
+[*.vb]
+indent_size = 4
+charset = utf-8
+
+###############################
+# .NET Coding Conventions     #
+###############################
+
+# Organize imports
+dotnet_sort_system_directives_first = true
+dotnet_separate_import_directive_groups = true
+
+# Me. preferences
+dotnet_style_qualification_for_field = false:suggestion
+dotnet_style_qualification_for_property = false:suggestion
+dotnet_style_qualification_for_method = false:suggestion
+dotnet_style_qualification_for_event = false:suggestion
+
+# Language keywords vs BCL types preferences
+dotnet_style_predefined_type_for_locals_parameters_members = true:suggestion
+dotnet_style_predefined_type_for_member_access = true:suggestion
+
+# Parentheses preferences
+dotnet_style_parentheses_in_arithmetic_binary_operators = never_if_unnecessary:none
+dotnet_style_parentheses_in_relational_binary_operators = never_if_unnecessary:none
+dotnet_style_parentheses_in_other_binary_operators = never_if_unnecessary:none
+dotnet_style_parentheses_in_other_operators = never_if_unnecessary:suggestion
+
+# Modifier preferences
+dotnet_style_require_accessibility_modifiers = always:suggestion
+dotnet_style_readonly_field = true:suggestion
+
+# Expression-level preferences
+dotnet_style_object_initializer = true:suggestion
+dotnet_style_collection_initializer = true:suggestion
+dotnet_style_explicit_tuple_names = true:suggestion
+dotnet_style_prefer_inferred_tuple_names = true:suggestion
+dotnet_style_prefer_inferred_anonymous_type_member_names = true:suggestion
+dotnet_style_prefer_auto_properties = true:suggestion
+dotnet_style_prefer_is_null_check_over_reference_equality_method = true:suggestion
+dotnet_style_prefer_conditional_expression_over_assignment = true:suggestion
+dotnet_style_prefer_conditional_expression_over_return = true:suggestion
+dotnet_style_coalesce_expression = true:suggestion
+dotnet_style_null_propagation = true:suggestion
+
+###############################
+# Naming Conventions          #
+###############################
+
+# Style Definitions
+dotnet_naming_style.pascal_case_style.capitalization = pascal_case
+
+# Use PascalCase for constant fields
+dotnet_naming_rule.constant_fields_should_be_pascal_case.severity = suggestion
+dotnet_naming_rule.constant_fields_should_be_pascal_case.symbols = constant_fields
+dotnet_naming_rule.constant_fields_should_be_pascal_case.style = pascal_case_style
+dotnet_naming_symbols.constant_fields.applicable_kinds = field
+dotnet_naming_symbols.constant_fields.applicable_accessibilities = *
+dotnet_naming_symbols.constant_fields.required_modifiers = const
+
+###################################
+# Visual Basic Coding Conventions #
+###################################
+visual_basic_preferred_modifier_order = Partial, Default, Private, Protected, Public, Friend, NotOverridable, Overridable, MustOverride, Overloads, Overrides, MustInherit, NotInheritable, Static, Shared, Shadows, ReadOnly, WriteOnly, Dim, Const, WithEvents, Widening, Narrowing, Custom, Async:suggestion
+visual_basic_style_unused_variable_expression_statement_preference = unused_local_variable:suggestion
+visual_basic_style_unused_value_assignment_preference = unused_local_variable:suggestion
+visual_basic_style_prefer_isnot_expression = true:suggestion
+visual_basic_style_prefer_simplified_object_creation = false:none
+dotnet_diagnostic.IDE0090.severity = none

exercises/practice/strain/.meta/Example.vb

@@ -0,0 +1,34 @@
+Imports System.Runtime.CompilerServices
+
+Public Module Strain
+    <Extension()>
+    Public Function Keep(Of T)(
+        ByVal collection As IEnumerable(Of T),
+        ByVal predicate As Func(Of T, Boolean)) As IEnumerable(Of T)
+
+        Return Filtered(collection, predicate)
+    End Function
+
+    <Extension()>
+    Public Function Discard(Of T)(
+        ByVal collection As IEnumerable(Of T),
+        ByVal predicate As Func(Of T, Boolean)) As IEnumerable(Of T)
+
+        Return Filtered(collection, Function(item) Not predicate(item))
+    End Function
+
+    Private Function Filtered(Of T)(
+        ByVal collection As IEnumerable(Of T),
+        ByVal predicate As Func(Of T, Boolean)) As IEnumerable(Of T)
+
+        Dim matches As New List(Of T)
+
+        For Each item In collection
+            If predicate(item) Then
+                matches.Add(item)
+            End If
+        Next
+
+        Return matches
+    End Function
+End Module

exercises/practice/strain/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "Strain.vb"
+    ],
+    "test": [
+      "StrainTests.vb"
+    ],
+    "example": [
+      ".meta/Example.vb"
+    ]
+  },
+  "blurb": "Implement the `keep` and `discard` operation on collections.",
+  "source": "Conversation with James Edward Gray II",
+  "source_url": "http://graysoftinc.com/"
+}

exercises/practice/strain/.meta/tests.toml

@@ -0,0 +1,52 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[26af8c32-ba6a-4eb3-aa0a-ebd8f136e003]
+description = "keep on empty list returns empty list"
+
+[f535cb4d-e99b-472a-bd52-9fa0ffccf454]
+description = "keeps everything"
+
+[950b8e8e-f628-42a8-85e2-9b30f09cde38]
+description = "keeps nothing"
+
+[92694259-6e76-470c-af87-156bdf75018a]
+description = "keeps first and last"
+
+[938f7867-bfc7-449e-a21b-7b00cbb56994]
+description = "keeps neither first nor last"
+
+[8908e351-4437-4d2b-a0f7-770811e48816]
+description = "keeps strings"
+
+[2728036b-102a-4f1e-a3ef-eac6160d876a]
+description = "keeps lists"
+
+[ef16beb9-8d84-451a-996a-14e80607fce6]
+description = "discard on empty list returns empty list"
+
+[2f42f9bc-8e06-4afe-a222-051b5d8cd12a]
+description = "discards everything"
+
+[ca990fdd-08c2-4f95-aa50-e0f5e1d6802b]
+description = "discards nothing"
+
+[71595dae-d283-48ca-a52b-45fa96819d2f]
+description = "discards first and last"
+
+[ae141f79-f86d-4567-b407-919eaca0f3dd]
+description = "discards neither first nor last"
+
+[daf25b36-a59f-4f29-bcfe-302eb4e43609]
+description = "discards strings"
+
+[a38d03f9-95ad-4459-80d1-48e937e4acaf]
+description = "discards lists"

exercises/practice/strain/Strain.vb

@@ -0,0 +1,19 @@
+Imports System.Runtime.CompilerServices
+
+Public Module Strain
+    <Extension()>
+    Public Function Keep(Of T)(
+        ByVal collection As IEnumerable(Of T),
+        ByVal predicate As Func(Of T, Boolean)) As IEnumerable(Of T)
+
+        Throw New NotImplementedException("You need to implement this function.")
+    End Function
+
+    <Extension()>
+    Public Function Discard(Of T)(
+        ByVal collection As IEnumerable(Of T),
+        ByVal predicate As Func(Of T, Boolean)) As IEnumerable(Of T)
+
+        Throw New NotImplementedException("You need to implement this function.")
+    End Function
+End Module

exercises/practice/strain/Strain.vbproj

@@ -0,0 +1,19 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <OutputType>Exe</OutputType>
+    <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Import Include="Xunit" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
+    <PackageReference Include="xunit.v3" Version="3.2.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" />
+  </ItemGroup>
+
+</Project>