Playing with this idea as a strategy pattern

build.yaml

@@ -0,0 +1,7 @@
+build:
+  source: .\src
+  output: .\output\bob
+  stages:
+    - clean
+    - copy
+    - test

readme.md

@@ -40,6 +40,13 @@ BuildJob src dst {
     TestStg
 } | Select stages
 
+Stages
+------
+{Clean, Copy, Test}
+
+# YAML Config
+PS> New-BuildFromYaml .\build.yaml | Select stages
+
 Stages
 ------
 {Clean, Copy, Test}

src/New-BuildFromYaml.ps1

@@ -0,0 +1,28 @@
+function New-BuildFromYaml {
+    [CmdletBinding()]
+    param (
+        # Specifies a path to one or more locations.
+        [Parameter(Mandatory=$true,
+                   Position=0,
+                   ParameterSetName="ParameterSetName",
+                   ValueFromPipeline=$true,
+                   ValueFromPipelineByPropertyName=$true,
+                   HelpMessage="Path to one or more locations.")]
+        [Alias("PSPath")]
+        [ValidateNotNullOrEmpty()]
+        [string[]]
+        $Path
+    )
+
+
+    $config = Get-Content -Path $Path -Raw | ConvertFrom-Yaml
+
+    $b = New-BuildJob -Path $config.build.source -Output $config.build.output
+
+    ForEach ($stageName in $config.build.stages) {
+        $stageObject = New-Object -TypeName $stageName
+        $b | Add-BuildStage -Stage $stageObject | Out-Null
+    }
+
+    Write-Output -InputObject $b
+}

src/bob.psm1

@@ -136,6 +136,7 @@ $global:BUILDER = New-Object -TypeName Object
 . $PSScriptRoot\Invoke-Builder.ps1
 . $PSScriptRoot\Write-BuilderResults.ps1
 . $PSScriptRoot\DSL.ps1
+. $PSScriptRoot\New-BuildFromYaml.ps1
 
 # Aliases
 if (!(Get-Alias -Name :Clean -ErrorAction SilentlyContinue)) { New-Alias -Name :Clean -Value Add-StageClean }

testStrategy.ps1

@@ -0,0 +1,34 @@
+<#
+    open/close principle
+    be open for extension, but closed for modification
+    an entity can allow its behaviour to be extended without modifying its source code
+#>
+
+Import-Module .\src\bob.psd1 -Force
+
+function testStrategy {
+    param($p)
+
+    $name = "Invoke-Build{0}" -f $p.gettype().name
+
+    if (!(Get-Command $name -ErrorAction SilentlyContinue)) {
+        return "$name not found"
+    }
+
+    "begin"
+    "call $name"
+    "end"
+    ""
+}
+
+function Invoke-BuildScriptBlock {}
+function Invoke-BuildString {}
+function Invoke-BuildTestThis {}
+
+class TestThis {}
+class TestThis1 {}
+
+testStrategy {}
+testStrategy .\quotes.xml
+testStrategy ([TestThis]::new())
+testStrategy ([TestThis1]::new())