Add argument selection handler to sample profile

PSReadLine/SamplePSReadLineProfile.ps1

@@ -600,3 +600,59 @@ Set-PSReadLineKeyHandler -Key RightArrow `
         [Microsoft.PowerShell.PSConsoleReadLine]::AcceptNextSuggestionWord($key, $arg)
     }
 }
+
+# Cycle through arguments on current line and select the text. This makes it easier to quickly change the argument if re-running a previously run command from the history
+# or if using a psreadline predictor. You can also use a digit argument to specify which argument you want to select, i.e. Alt+1, Alt+a selects the first argument
+# on the command line. 
+Set-PSReadLineKeyHandler -Key Alt+a `
+                         -BriefDescription SelectCommandArguments `
+                         -LongDescription "Set current selection to next command argument in the command line. Use of digit argument selects argument by position" `
+                         -ScriptBlock {
+    param($key, $arg)
+
+    $ast = $null
+    $cursor = $null
+    [Microsoft.PowerShell.PSConsoleReadLine]::GetBufferState([ref]$ast, [ref]$null, [ref]$null, [ref]$cursor)
+
+    $asts = $ast.FindAll( {
+        $args[0] -is [System.Management.Automation.Language.ExpressionAst] -and
+        $args[0].Parent -is [System.Management.Automation.Language.CommandAst] -and
+        $args[0].Extent.StartOffset -ne $args[0].Parent.Extent.StartOffset
+      }, $true)
+
+    if ($asts.Count -eq 0) {
+        [Microsoft.PowerShell.PSConsoleReadLine]::Ding()
+        return
+    }
+
+    $nextAst = $null
+
+    if ($null -ne $arg) {
+        $nextAst = $asts[$arg - 1]
+    }
+    else {
+        foreach ($ast in $asts) {
+            if ($ast.Extent.StartOffset -ge $cursor) {
+                $nextAst = $ast
+                break
+            }
+        } 
+
+        if ($null -eq $nextAst) {
+            $nextAst = $asts[0]
+        }
+    }
+
+    $startOffsetAdjustment = 0
+    $endOffsetAdjustment = 0
+
+    if ($nextAst -is [System.Management.Automation.Language.StringConstantExpressionAst] -and
+        $nextAst.StringConstantType -ne [System.Management.Automation.Language.StringConstantType]::BareWord) {
+            $startOffsetAdjustment = 1
+            $endOffsetAdjustment = 2
+    }
+
+    [Microsoft.PowerShell.PSConsoleReadLine]::SetCursorPosition($nextAst.Extent.StartOffset + $startOffsetAdjustment)
+    [Microsoft.PowerShell.PSConsoleReadLine]::SetMark($null, $null)
+    [Microsoft.PowerShell.PSConsoleReadLine]::SelectForwardChar($null, ($nextAst.Extent.EndOffset - $nextAst.Extent.StartOffset) - $endOffsetAdjustment)
+}