PowerShell · iSazonov · Apr 21, 2025 · Apr 5, 2025 · Apr 5, 2025 · Apr 5, 2025
@@ -41,7 +41,7 @@ public sealed class JoinStringCommand : PSCmdlet
         /// Gets or sets the delimiter to join the output with.
         /// </summary>
         [Parameter(Position = 1)]
-        [ArgumentCompleter(typeof(JoinItemCompleter))]
+        [ArgumentCompleter(typeof(SeparatorArgumentCompleter))]
         [AllowEmptyString]
         public string Separator
         {
@@ -79,7 +79,7 @@ public string Separator
         /// Gets or sets a format string that is applied to each input object.
         /// </summary>
         [Parameter(ParameterSetName = "Format")]
-        [ArgumentCompleter(typeof(JoinItemCompleter))]
+        [ArgumentCompleter(typeof(FormatStringArgumentCompleter))]
         public string FormatString { get; set; }
 
         /// <summary>
@@ -160,79 +160,100 @@ protected override void EndProcessing()
         }
     }
 
-    [SuppressMessage(
-        "Microsoft.Performance",
-        "CA1812:AvoidUninstantiatedInternalClasses",
-        Justification = "Class is instantiated through late-bound reflection")]
-    internal class JoinItemCompleter : IArgumentCompleter
+    /// <summary>
+    /// Provides completion for the Separator parameter of the Join-String cmdlet.
+    /// </summary>
+    public sealed class SeparatorArgumentCompleter : IArgumentCompleter
     {
-        public IEnumerable<CompletionResult> CompleteArgument(
-            string commandName,
-            string parameterName,
-            string wordToComplete,
-            CommandAst commandAst,
-            IDictionary fakeBoundParameters)
-        {
-            switch (parameterName)
-            {
-                case "Separator": return CompleteSeparator(wordToComplete);
-                case "FormatString": return CompleteFormatString(wordToComplete);
-            }
-
-            return null;
-        }
+        private static readonly string NewLineText =
+#if UNIX
+        "`n";
+#else
+        "`r`n";
+#endif
 
-        private static IEnumerable<CompletionResult> CompleteFormatString(string wordToComplete)
+        private static readonly Dictionary<string, (string Tooltip, string ListItemText)> s_separatorMappings = new(capacity: 7)
         {
-            var res = new List<CompletionResult>();
-            void AddMatching(string completionText)
-            {
-                if (completionText.StartsWith(wordToComplete, StringComparison.OrdinalIgnoreCase))
-                {
-                    res.Add(new CompletionResult(completionText));
-                }
-            }
+            { ",", (TabCompletionStrings.SeparatorCommaToolTip, "Comma") },
+            { ", ", (TabCompletionStrings.SeparatorCommaSpaceToolTip, "Comma-Space") },
+            { ";", (TabCompletionStrings.SeparatorSemiColonToolTip, "Semi-Colon") },
+            { "; ", (TabCompletionStrings.SeparatorSemiColonSpaceToolTip, "Semi-Colon-Space") },
+            { NewLineText, (StringUtil.Format(TabCompletionStrings.SeparatorNewlineToolTip, NewLineText), "Newline") },
+            { "-", (TabCompletionStrings.SeparatorDashToolTip, "Dash") },
+            { " ", (TabCompletionStrings.SeparatorSpaceToolTip, "Space") },
+        };
 
-            AddMatching("'[{0}]'");
-            AddMatching("'{0:N2}'");
-            AddMatching("\"`r`n    `${0}\"");
-            AddMatching("\"`r`n    [string] `${0}\"");
+        private static readonly IEnumerable<string> s_separatorValues = s_separatorMappings.Keys;
 
-            return res;
-        }
-
-        private IEnumerable<CompletionResult> CompleteSeparator(string wordToComplete)
-        {
-            var res = new List<CompletionResult>(10);
+        private static string GetSeparatorToolTip(string separator)
+            => s_separatorMappings.TryGetValue(separator, out var mapping)
+                ? mapping.Tooltip
+                : separator;
 
-            void AddMatching(string completionText, string listText, string toolTip)
-            {
-                if (completionText.StartsWith(wordToComplete, StringComparison.OrdinalIgnoreCase))
-                {
-                    res.Add(new CompletionResult(completionText, listText, CompletionResultType.ParameterValue, toolTip));
-                }
-            }
+        private static string GetSeparatorListItemText(string separator)
+            => s_separatorMappings.TryGetValue(separator, out var mapping)
+                ? mapping.ListItemText
+                : separator;
 
-            AddMatching("', '", "Comma-Space", "', ' - Comma-Space");
-            AddMatching("';'", "Semi-Colon", "';'  - Semi-Colon ");
-            AddMatching("'; '", "Semi-Colon-Space", "'; ' - Semi-Colon-Space");
-            AddMatching($"\"{NewLineText}\"", "Newline", $"{NewLineText} - Newline");
-            AddMatching("','", "Comma", "','  - Comma");
-            AddMatching("'-'", "Dash", "'-'  - Dash");
-            AddMatching("' '", "Space", "' '  - Space");
-            return res;
-        }
+        /// <summary>
+        /// Returns completion results for Separator parameter.
+        /// </summary>
+        /// <param name="commandName">The command name.</param>
+        /// <param name="parameterName">The parameter name.</param>
+        /// <param name="wordToComplete">The word to complete.</param>
+        /// <param name="commandAst">The command AST.</param>
+        /// <param name="fakeBoundParameters">The fake bound parameters.</param>
+        /// <returns>List of Completion Results.</returns>
+        public IEnumerable<CompletionResult> CompleteArgument(
+            string commandName,
+            string parameterName,
+            string wordToComplete,
+            CommandAst commandAst,
+            IDictionary fakeBoundParameters)
+                => CompletionHelpers.GetMatchingResults(
+                    wordToComplete,
+                    possibleCompletionValues: s_separatorValues,
+                    listItemTextMapping: GetSeparatorListItemText,
+                    toolTipMapping: GetSeparatorToolTip,
+                    resultType: CompletionResultType.ParameterValue);
+    }
 
-        public string NewLineText
+    /// <summary>
+    /// Provides completion for the FormatString parameter of the Join-String cmdlet.
+    /// </summary>
+    public sealed class FormatStringArgumentCompleter : IArgumentCompleter
+    {
+        private static readonly IReadOnlyList<string> s_formatStringValues = new List<string>(capacity: 4)
         {
-            get
-            {
+            "[{0}]",
+            "{0:N2}",
 #if UNIX
-                return "`n";
+            "`n    `${0}",
+            "`n    [string] `${0}",
 #else
-                return "`r`n";
+            "`r`n    `${0}",
+            "`r`n    [string] `${0}",
 #endif
-            }
-        }
+        };
+
+        /// <summary>
+        /// Returns completion results for FormatString parameter.
+        /// </summary>
+        /// <param name="commandName">The command name.</param>
+        /// <param name="parameterName">The parameter name.</param>
+        /// <param name="wordToComplete">The word to complete.</param>
+        /// <param name="commandAst">The command AST.</param>
+        /// <param name="fakeBoundParameters">The fake bound parameters.</param>
+        /// <returns>List of Completion Results.</returns>
+        public IEnumerable<CompletionResult> CompleteArgument(
+            string commandName,
+            string parameterName,
+            string wordToComplete,
+            CommandAst commandAst,
+            IDictionary fakeBoundParameters)
+                => CompletionHelpers.GetMatchingResults(
+                    wordToComplete,
+                    possibleCompletionValues: s_formatStringValues,
+                    matchStrategy: CompletionHelpers.WildcardPatternEscapeMatch);
     }
 }