Add -Extension parameter for extension methods (#35)

Author: SeeminglyScience

docs/en-US/Find-Member.md

@@ -16,13 +16,13 @@ Find properties, methods, fields, etc that fit specific criteria.
 
 ```powershell
 
-Find-Member [[-FilterScript] <scriptblock>] [-ParameterType <ScriptBlockStringOrType>] [-GenericParameter <ScriptBlockStringOrType>] [-ParameterCount <RangeExpression[]>] [-GenericParameterCount <RangeExpression[]>] [-ReturnType <ScriptBlockStringOrType>] [-IncludeSpecialName] [-Decoration <ScriptBlockStringOrType>] [-MemberType <MemberTypes>] [-Static] [-Instance] [-Abstract] [-Virtual] [-Declared] [-IncludeObject] [-RecurseNestedType] [-Name <string>] [-Force] [-RegularExpression] [-InputObject <psobject>] [-Not] [-ResolutionMap <hashtable>] [-AccessView <AccessView>] [<CommonParameters>]
+Find-Member [[-FilterScript] <scriptblock>] [-ParameterType <ScriptBlockStringOrType>] [-GenericParameter <ScriptBlockStringOrType>] [-ParameterCount <RangeExpression[]>] [-GenericParameterCount <RangeExpression[]>] [-ReturnType <ScriptBlockStringOrType>] [-IncludeSpecialName] [-Decoration <ScriptBlockStringOrType>] [-MemberType <MemberTypes>] [-Static] [-Instance] [-Abstract] [-Virtual] [-Declared] [-IncludeObject] [-RecurseNestedType] [-Extension] [-Name <string>] [-Force] [-RegularExpression] [-InputObject <psobject>] [-Not] [-ResolutionMap <hashtable>] [-AccessView <AccessView>] [<CommonParameters>]
 ```
 
 ### ByName
 
 ```powershell
-Find-Member [[-Name] <string>] [-ParameterType <ScriptBlockStringOrType>] [-GenericParameter <ScriptBlockStringOrType>] [-ParameterCount <RangeExpression[]>] [-GenericParameterCount <RangeExpression[]>] [-ReturnType <ScriptBlockStringOrType>] [-IncludeSpecialName] [-Decoration <ScriptBlockStringOrType>] [-MemberType <MemberTypes>] [-Static] [-Instance] [-Abstract] [-Virtual] [-Declared] [-IncludeObject] [-RecurseNestedType] [-FilterScript <scriptblock>] [-Force] [-RegularExpression] [-InputObject <psobject>] [-Not] [-ResolutionMap <hashtable>] [-AccessView <AccessView>] [<CommonParameters>]
+Find-Member [[-Name] <string>] [-ParameterType <ScriptBlockStringOrType>] [-GenericParameter <ScriptBlockStringOrType>] [-ParameterCount <RangeExpression[]>] [-GenericParameterCount <RangeExpression[]>] [-ReturnType <ScriptBlockStringOrType>] [-IncludeSpecialName] [-Decoration <ScriptBlockStringOrType>] [-MemberType <MemberTypes>] [-Static] [-Instance] [-Abstract] [-Virtual] [-Declared] [-IncludeObject] [-RecurseNestedType] [-Extension] [-FilterScript <scriptblock>] [-Force] [-RegularExpression] [-InputObject <psobject>] [-Not] [-ResolutionMap <hashtable>] [-AccessView <AccessView>] [<CommonParameters>]
 ```
 
 ## DESCRIPTION
@@ -604,6 +604,23 @@ Accept pipeline input: False
 Accept wildcard characters: False
 ```
 
+### -Extension
+
+When specified, members must be decorated with `ExtensionAttribute` to match. This
+is how the C# compiler marks extension methods like those found in `System.Linq.Enumerable`.
+
+```yaml
+Type: SwitchParameter
+Parameter Sets: (All)
+Aliases: ext
+
+Required: False
+Position: Named
+Default value: None
+Accept pipeline input: False
+Accept wildcard characters: False
+```
+
 ### -ResolutionMap
 
 Specifies a hashtable of `name` to `ScriptBlockStringOrType` to create your own keywords and/or override type resolution for any signature in this command.

src/ClassExplorer/Commands/FindMemberCommand.cs

@@ -181,6 +181,14 @@ public SwitchParameter RecurseNestedType
             set => _options.RecurseNestedType = value;
         }
 
+        [Parameter]
+        [Alias("ext")]
+        public SwitchParameter Extension
+        {
+            get => _options.Extension;
+            set => _options.Extension = value;
+        }
+
         private MemberSearch<PipelineEmitter<MemberInfo>> _search = null!;
 
         private protected override void OnNoInput()

src/ClassExplorer/MemberSearch.cs

@@ -138,6 +138,11 @@ private static bool IsStatic(MemberInfo member)
 
     private void SearchSingleType(Type type)
     {
+        if (_options.Extension && !_options.Not && !type.IsDefined(typeof(ExtensionAttribute)))
+        {
+            return;
+        }
+
         type.FindMembers(
             _options.MemberType,
             _flags,
@@ -211,6 +216,11 @@ protected override void InitializeFastFilters(List<Filter<MemberInfo>> filters,
             filters.AddFilter(static (member, _) => member.DeclaringType == member.ReflectedType);
         }
 
+        if (_options.Extension)
+        {
+            filters.AddFilter(static (member, _) => member.IsDefined(typeof(ExtensionAttribute)));
+        }
+
         if (!_options.IncludeObject)
         {
             filters.AddFilter(

src/ClassExplorer/MemberSearchOptions.cs

@@ -33,4 +33,6 @@ internal class MemberSearchOptions : ReflectionSearchOptions
     public bool IncludeObject { get; set; }
 
     public bool RecurseNestedType { get; set; }
+
+    public bool Extension { get; set; }
 }

src/ClassExplorer/SignatureWriter.cs

@@ -710,6 +710,14 @@ public SignatureWriter TypeInfo(ParameterInfo parameter)
     {
         RefModifier(parameter);
 
+        if (parameter.Position is 0
+            && parameter.Member is MethodInfo method
+            && method.IsStatic
+            && method.IsDefined(typeof(ExtensionAttribute)))
+        {
+            Keyword("this").Space();
+        }
+
         if (parameter.IsDefined(typeof(ParamArrayAttribute), inherit: false))
         {
             Keyword("params").Space();