context_menu.ps1

$Item = Get-Content $args[0] | ConvertFrom-Json


New-PSDrive -Name HKCR -PSProvider Registry -Root HKEY_CLASSES_ROOT

$Item.locations | ForEach-Object {
    Write-Output ($_.path + "\" + $Item.key)

    if (Test-Path -LiteralPath ($_.path + "\" + $Item.key)) {
        Remove-Item -LiteralPath ($_.path + "\" + $Item.key) -Recurse
    }

    Push-Location -LiteralPath $_.path
    New-Item -Name $Item.key -Value $_.text
    New-ItemProperty -Path $Item.key -Name "Icon" -Value $Item.icon
    New-Item -Name ($Item.key + "\command") -Value ($Item.executable + " `"" + $_.target + "`"")
    Pop-Location
}

Remove-PSDrive -Name HKCR

sublime_merge.json

{
    "executable": "C:\\Program Files\\Sublime Merge\\sublime_merge.exe",
    "icon": "C:\\Program Files\\Sublime Merge\\sublime_merge.exe",
    "key": "Sublime Merge",
    "locations": [
        {
            "path": "HKCR:\\Directory\\shell",
            "target": "%1",
            "text": "Open with Sublime Merge"
        },
        {
            "path": "HKCR:\\Directory\\Background\\shell",
            "target": "%V",
            "text": "Open Sublime Merge here"
        }
    ]
}

sublime_text.json

{
    "executable": "C:\\Program Files\\Sublime Text\\sublime_text.exe",
    "icon": "C:\\Program Files\\Sublime Text\\sublime_text.exe",
    "key": "Sublime Text",
    "locations": [
        {
            "path": "HKCR:\\*\\shell",
            "target": "%1",
            "text": "Open with Sublime Text"
        },
        {
            "path": "HKCR:\\Directory\\shell",
            "target": "%1",
            "text": "Open with Sublime Text"
        },
        {
            "path": "HKCR:\\Directory\\Background\\shell",
            "target": "%V",
            "text": "Open Sublime Text here"
        }
    ]
}