PythonTools.psm1

function Get-PythonVersions {
    (get-item HKCU:\Software\Python\PythonCore).GetSubKeyNames()
}

function Get-DefaultPython {

    $pythons = Get-PythonVersions | ForEach-Object{Get-ItemProperty "hkcu:\Software\Python\PythonCore\$_"}

    $x64Pythons = $pythons | Where-Object{$_.SysArchitecture.StartsWith("64")} | Sort-Object -Property SysVersion -Descending
    if ($x64Pythons.Length -gt 0)
    {
        return $x64Pythons[0].PSChildName
    }
    $x86Pythons = $pythons | Where-Object{$_.SysArchitecture.StartsWith("32")} | Sort-Object -Property SysVersion -Descending
    if ($x86Pythons.Length -gt 0)
    {
        return $x86Pythons[0].PSChildName
    }

    throw "Python not installed"
}

function Get-PythonFolder {
[CmdletBinding()]
Param()
DynamicParam 
{
    New-DynamicParameter -Name version -ValidateSet (Get-PythonVersions) -Type ([string])
}
process 
{
    $version = $PSBoundParameters["version"]
    if ($null -eq $version)
    {
        $version = Get-DefaultPython
    }
    (Get-ItemProperty "hkcu:\Software\Python\PythonCore\$version\InstallPath")."(default)";
}
}

export-ModuleMember -Function Get-PythonVersions, Get-DefaultPython, Get-PythonFolder

Get-PythonVersions | ForEach-Object{
    $folder = Get-PythonFolder -version $_
    $suffix = $_.replace(".", "").replace("-32", "x86")

    set-alias "py$suffix" (join-path $folder python.exe)
    set-alias "dpy$suffix" (join-path $folder python_d.exe)
    Export-ModuleMember -alias "py$suffix", "dpy$suffix"
}

$defaultPython = Get-DefaultPython
if ($null -ne $defaultPython) {
    $folder = Get-PythonFolder -version $defaultPython
    set-alias "dpy" (join-path $folder python_d.exe)
    Export-ModuleMember -alias "dpy"
}