[Draft] Adding --format support to dotnet new list

src/Cli/Microsoft.TemplateEngine.Cli/Commands/SymbolStrings.resx

@@ -265,4 +265,7 @@ If command is specified without the argument, it lists all the template packages
   <data name="TemplateCommand_Option_Type" xml:space="preserve">
     <value>Specifies the template type to instantiate.</value>
   </data>
+  <data name="ListCommand_Option_Format" xml:space="preserve">
+    <value>Specifies the output format type for the list packages command</value>
+  </data>
 </root>

src/Cli/Microsoft.TemplateEngine.Cli/Commands/list/BaseListCommand.cs

@@ -29,6 +29,7 @@ internal BaseListCommand(
 
             Arguments.Add(NameArgument);
             Options.Add(IgnoreConstraintsOption);
+            Options.Add(FormatOption);
             Options.Add(SharedOptions.OutputOption);
             Options.Add(SharedOptions.ProjectPathOption);
             SetupTabularOutputOptions(this);
@@ -46,6 +47,13 @@ internal BaseListCommand(
             Arity = new ArgumentArity(0, 1)
         };
 
+        internal static CliOption<FormatOptions> FormatOption { get; } = new("--format")
+        {
+            AllowMultipleArgumentsPerToken = true,
+            Description = SymbolStrings.ListCommand_Option_Format,
+            Arity = new ArgumentArity(1, 1),
+        };
+
         internal static CliArgument<string> NameArgument { get; } = new("template-name")
         {
             Description = SymbolStrings.Command_List_Argument_Name,
@@ -72,4 +80,12 @@ protected override Task<NewCommandStatus> ExecuteAsync(
         protected override ListCommandArgs ParseContext(ParseResult parseResult) => new(this, parseResult);
 
     }
+
+#pragma warning disable SA1201 // Elements should appear in the correct order
+    public enum FormatOptions
+    {
+        Console,
+        Json
+    }
+#pragma warning restore SA1201 // Elements should appear in the correct order
 }

src/Cli/Microsoft.TemplateEngine.Cli/Commands/list/ListCommandArgs.cs

@@ -29,6 +29,7 @@ internal ListCommandArgs(BaseListCommand command, ParseResult parseResult) : bas
                 Language = GetFilterValue(FilterOptionDefinition.LanguageFilter);
             }
             IgnoreConstraints = parseResult.GetValue(BaseListCommand.IgnoreConstraintsOption);
+            FormatOptions = ParseResult.GetValue(BaseListCommand.FormatOption);
         }
 
         public bool DisplayAllColumns { get; }
@@ -40,5 +41,7 @@ internal ListCommandArgs(BaseListCommand command, ParseResult parseResult) : bas
         internal string? Language { get; }
 
         internal bool IgnoreConstraints { get; }
+
+        internal FormatOptions FormatOptions { get; }
     }
 }

src/Cli/Microsoft.TemplateEngine.Cli/TabularOutput/TemplateGroupDisplay.cs

@@ -5,6 +5,7 @@
 using Microsoft.TemplateEngine.Abstractions;
 using Microsoft.TemplateEngine.Cli.Commands;
 using Microsoft.TemplateEngine.Utils;
+using Newtonsoft.Json;
 
 namespace Microsoft.TemplateEngine.Cli.TabularOutput
 {
@@ -27,14 +28,23 @@ internal static void DisplayTemplateList(
             IEnumerable<TemplateGroup> templateGroups,
             TabularOutputSettings helpFormatterSettings,
             IReporter reporter,
-            string? selectedLanguage = null)
+            string? selectedLanguage = null,
+            FormatOptions format = FormatOptions.Console)
         {
             IReadOnlyCollection<TemplateGroupTableRow> groupsForDisplay = GetTemplateGroupsForListDisplay(
                 templateGroups,
                 selectedLanguage,
                 engineEnvironmentSettings.GetDefaultLanguage(),
                 engineEnvironmentSettings.Environment);
+
+            if (format == FormatOptions.Json)
+            {
+                DisplayJsonTemplateList(groupsForDisplay, reporter);
+                return;
+            }
+
             DisplayTemplateList(groupsForDisplay, helpFormatterSettings, reporter);
+
         }
 
         /// <summary>
@@ -54,16 +64,30 @@ internal static void DisplayTemplateList(
             IEnumerable<ITemplateInfo> templates,
             TabularOutputSettings helpFormatterSettings,
             IReporter reporter,
-            string? selectedLanguage = null)
+            string? selectedLanguage = null,
+            FormatOptions format = FormatOptions.Console)
         {
             IReadOnlyCollection<TemplateGroupTableRow> groupsForDisplay = GetTemplateGroupsForListDisplay(
                 templates,
                 selectedLanguage,
                 engineEnvironmentSettings.GetDefaultLanguage(),
                 engineEnvironmentSettings.Environment);
+            if (format == FormatOptions.Json)
+            {
+                DisplayJsonTemplateList(groupsForDisplay, reporter);
+                return;
+            }
+
             DisplayTemplateList(groupsForDisplay, helpFormatterSettings, reporter);
         }
 
+        internal static void DisplayJsonTemplateList(IReadOnlyCollection<TemplateGroupTableRow> groupsForDisplay, IReporter reporter)
+        {
+            //var result = JsonSerializer.Serialize(groupsForDisplay);
+            var result = JsonConvert.SerializeObject(groupsForDisplay);
+            reporter.WriteLine(result);
+        }
+
         /// <summary>
         /// Displays the template languages.
         /// </summary>

src/Cli/Microsoft.TemplateEngine.Cli/TabularOutput/TemplateGroupTableRow.cs

@@ -6,18 +6,18 @@ namespace Microsoft.TemplateEngine.Cli.TabularOutput
     /// <summary>
     /// Represents a table row for template group display.
     /// </summary>
-    internal struct TemplateGroupTableRow
+    public struct TemplateGroupTableRow
     {
-        internal string Author { get; set; }
+        public string Author { get; set; }
 
-        internal string Classifications { get; set; }
+        public string Classifications { get; set; }
 
-        internal string Languages { get; set; }
+        public string Languages { get; set; }
 
-        internal string Name { get; set; }
+        public string Name { get; set; }
 
-        internal string ShortNames { get; set; }
+        public string ShortNames { get; set; }
 
-        internal string Type { get; set; }
+        public string Type { get; set; }
     }
 }

src/Cli/Microsoft.TemplateEngine.Cli/TemplateListCoordinator.cs

@@ -60,7 +60,8 @@ internal async Task<NewCommandStatus> DisplayTemplateGroupListAsync(
                     resolutionResult.TemplateGroupsWithMatchingTemplateInfoAndParameters,
                     settings,
                     reporter: Reporter.Output,
-                    selectedLanguage: args.Language);
+                    selectedLanguage: args.Language,
+                    format: args.FormatOptions);
                 return NewCommandStatus.Success;
             }
             else