Transparent wrapper using data object

transparent wrapper.ps1

# getting a piece of code from a user that we want to wrap, 
# and execute, we often need to pass in additional parameters
# at least the script itself, and this poses a problem because 
# the parameter name will conflict with the user script. 

# (we want to add a wrapper for example to run two pieces of code 
# in the same scope, without leaking variables into a parent scope)

# here for simplicity all the scriptblocks are running in the 
# same session state, and we chose variable $A to pass the user
# provided scriptblock into our wrapper. This $A variable conflicts with
# a variable that the user defined and so it would be best if our wrapper 
# used no variables and was completely transparent

Add-Type -TypeDefinition "
using System.Collections.Generic;
public class Container { 
    static Container () { 
        _data = new Dictionary<string,object>();
    }
    private static Dictionary<string,object> _data;
    public static Dictionary<string,object> Data { get { return _data; } } 
}"


# opaque wrapper, the result the content of $userCode -> '$A' instead of
# the correct value "abc" because we chose a conflicting variable name
$A = "abc"
$userCode = { $A }

& { 
    param ($A)
    &$A

} $userCode

# transparent wrapper, the offending variable is removed and it's contents
# are stored in and retrieved from a container object

[Container]::Data.Clear()

& { 
    param ($A)
    [Container]::Data.Add("A", $A)
    Remove-Variable -Scope Local -Name A 
    &([Container]::Data.A)

} $userCode

I forgot about the private: scope of parameters. So this can all be avoided by doing this:

$A = "abc"
$userCode = { $A }

& { 
    param ($private:A) # <---
    & $A
    
} $userCode