WIP: Evaluate variables on hover

src/PowerShellEditorServices/Services/PowerShell/Handlers/EvaluateHandler.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System.Collections.Generic;
 using System.Management.Automation;
 using System.Threading;
 using System.Threading.Tasks;
@@ -22,9 +23,9 @@ internal class EvaluateHandler : IEvaluateHandler
         public async Task<EvaluateResponseBody> Handle(EvaluateRequestArguments request, CancellationToken cancellationToken)
         {
             // This API is mostly used for F8 execution so it requires the foreground.
-            await _executionService.ExecutePSCommandAsync(
+            IReadOnlyList<PSObject> results = await _executionService.ExecutePSCommandAsync<PSObject>(
                 new PSCommand().AddScript(request.Expression),
-                CancellationToken.None,
+                cancellationToken,
                 new PowerShellExecutionOptions
                 {
                     RequiresForeground = true,
@@ -34,10 +35,9 @@ public async Task<EvaluateResponseBody> Handle(EvaluateRequestArguments request,
                     ThrowOnError = false,
                 }).ConfigureAwait(false);
 
-            // TODO: Should we return a more informative result?
             return new EvaluateResponseBody
             {
-                Result = "",
+                Result = string.Join(System.Environment.NewLine, results),
                 VariablesReference = 0
             };
         }

src/PowerShellEditorServices/Services/TextDocument/Handlers/HoverHandler.cs

@@ -1,11 +1,15 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System;
 using System.Collections.Generic;
+using System.Management.Automation;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
 using Microsoft.PowerShell.EditorServices.Services;
+using Microsoft.PowerShell.EditorServices.Services.PowerShell;
+using Microsoft.PowerShell.EditorServices.Services.PowerShell.Execution;
 using Microsoft.PowerShell.EditorServices.Services.Symbols;
 using Microsoft.PowerShell.EditorServices.Services.TextDocument;
 using Microsoft.PowerShell.EditorServices.Utility;
@@ -18,15 +22,18 @@ namespace Microsoft.PowerShell.EditorServices.Handlers
     internal class PsesHoverHandler : HoverHandlerBase
     {
         private readonly ILogger _logger;
+        private readonly IInternalPowerShellExecutionService _executionService;
         private readonly SymbolsService _symbolsService;
         private readonly WorkspaceService _workspaceService;
 
         public PsesHoverHandler(
             ILoggerFactory factory,
+            IInternalPowerShellExecutionService executionService,
             SymbolsService symbolsService,
             WorkspaceService workspaceService)
         {
             _logger = factory.CreateLogger<PsesHoverHandler>();
+            _executionService = executionService;
             _symbolsService = symbolsService;
             _workspaceService = workspaceService;
         }
@@ -63,6 +70,21 @@ public override async Task<Hover> Handle(HoverParams request, CancellationToken
                 new MarkedString("PowerShell", symbolDetails.SymbolReference.Name)
             };
 
+            // If we're looking at a variable, try to get its value.
+            if (symbolDetails.SymbolReference.Type == SymbolType.Variable)
+            {
+                PSCommand command = new PSCommand().AddScript($"[System.Diagnostics.DebuggerHidden()]param() {symbolDetails.SymbolReference.Name}");
+                IReadOnlyList<PSObject> results = await _executionService.ExecutePSCommandAsync<PSObject>(
+                    command,
+                    cancellationToken,
+                    new PowerShellExecutionOptions { ThrowOnError = false }).ConfigureAwait(false);
+
+                if (results != null)
+                {
+                    symbolInfo.Add(new MarkedString("PowerShell", string.Join(Environment.NewLine, results)));
+                }
+            }
+
             if (!string.IsNullOrEmpty(symbolDetails.Documentation))
             {
                 symbolInfo.Add(new MarkedString("markdown", symbolDetails.Documentation));