PowerShell Function Factory

Reading Managing Records in Python 

For many years there was no record type in the Python language […] Guido never considered that request […] "in real life you always need to add methods to your data, so just use a custom class"

In PowerShell you can create property bags two ways, Add-Member and Select-Object. Often you need a function that takes parameters and returns an object to hold some data.  Typing this out takes time, tweaking and testing.

Below, New-Function generates your function. This example creates a function named New-Pair that takes two parameters, item1 and item2.

Notice the next line uses the newly created function.

New-Function 'New-Pair' 'item1 item2'            

New-Pair 1 2 | Format-Table -AutoSize

Another Example

New-Function creates a PowerShell function so parameter binding works too.

New-Function `
  'New-Person' 'FirstName LastName Address City State Zip'            

New-Person John Doe -Zip 10001

The Factory

Function New-Function ($name, $properties) {
    $parts = $properties.trim().split(' ')
    $parts |
        %{
            $selectProperties += @"
 @{
            Name = '$_'
            Expression = {`$$_}
        },
"@
        }            

# simple way to remove the trailing comma        
$selectProperties = $selectProperties -Replace ",$", ""            

Invoke-Expression @"
Function Global:$name {
param(`$$($parts -join ',$'))

New-Object PSObject |
    select $selectProperties
}
"@
}

Grab The Code