Simplify a Powershell one-line function that works with pipelines as well as conventional parameters

Question

I have the following PowerShell function that works as intended for pipeline and paramater usage:

function ext { 
  process {
    [System.IO.Path]::ChangeExtension($_ ? $_ : $args[0], $_ ? $args[0] : $args[1])
  }
}

Is it possible to simplify/minify this function by maybe using some Automatic Variables I don't know about, but without lengthening the code.

I explicitly don't want to go through all the parameter syntax like [Parameter(ValueFromPipeline=$True)] and defining each parameter explicitly since it would double the length of the function, which is exactly not my goal, unlike in these posts:

• Make a Powershell function work correctly as both Pipeline and normal invocation
• Handling pipeline and parameter input in a Powershell function

Answer 1

The only possible simplifications to your current code are using a filter instead of a function with a process and removing System from System.IO.Path. There is no automatic variable that covers pipeline and positional binding both in 1.

filter ext { [IO.Path]::ChangeExtension($_ ? $_ : $args[0], $_ ? $args[0] : $args[1]) }

If you want to give your code more meaning or context you could use .ExpectingInput in your conditions however this makes it longer:

filter ext {
    [IO.Path]::ChangeExtension(
        $MyInvocation.ExpectingInput ? $_ : $args[0],
        $MyInvocation.ExpectingInput ? $args[0] : $args[1])
}