feat: Set-Turtle ( Fixes #65 )

Author: James Brundage

Commands/Set-Turtle.ps1

@@ -0,0 +1,61 @@
+function Set-Turtle {
+    <#
+    .SYNOPSIS
+        Sets a turtle.
+    .DESCRIPTION
+        Changes properties of a turtle, and returns the turtle.
+    .EXAMPLE
+        New-Turtle | 
+            Move-Turtle SierpinskiTriangle 20 3 |
+            Set-Turtle -Property Stroke -Value '#4488ff' |
+            Save-Turtle "./SierpinskiTriangle.svg"
+    #>
+    param(
+    # The property of the turtle to set.
+    [Parameter(Mandatory)]
+    [ArgumentCompleter({
+        param ( $commandName,
+            $parameterName,
+            $wordToComplete,
+            $commandAst,
+            $fakeBoundParameters )
+        $myInv = $myInvocation
+        $turtleType = Get-TypeData -TypeName Turtle
+        $propertyNames = @(foreach ($memberName in $turtleType.Members.Keys) {
+            if ($turtleType.Members[$memberName] -is [System.Management.Automation.Runspaces.ScriptPropertyData] -and
+                $turtleType.Members[$memberName].SetScriptBlock) {
+                $memberName
+            }
+        })
+                
+        if ($wordToComplete) {
+            return $propertyNames -like "$wordToComplete*"            
+        } else {
+            return $propertyNames
+        }
+    })]
+    [string]
+    $Property = 'Stroke',
+    
+    # The value to set.
+    [PSObject]
+    $Value,
+
+    # The turtle input object.
+    [Parameter(ValueFromPipeline)]
+    [Alias('Turtle')]
+    [PSObject]
+    $InputObject
+    )
+
+    process {
+        if (-not $inputObject) { return }
+        $propInfo = $inputObject.psobject.properties[$property]
+        if (-not $propInfo.SetterScript) {
+            Write-Error "Property '$property' can not be set."
+            return
+        }
+        $inputObject.$property = $Value
+        return $inputObject
+    }
+}