PowerShell / PowerShell/PowerShellEditorServices

Discussion: Different method of passing $Context to Editor Commands

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Description

I wanted to start a discussion on how PSES could improve the way it passes $Context to Editor Commands.

The way $Context is made accessible to an Editor Command currently, is it is passed as a parameter to the Command. This is not immediately evident and I can see this causing confusion.

In a scriptblock, this can be handled by adding a context param.

Register-EditorCommand `
        -Name "Teamviewer.ConnectDevice" `
        -DisplayName "Connect to Teamviewer Device" `
        -SuppressOutput `
        -ScriptBlock {
            param([Microsoft.PowerShell.EditorServices.Extensions.EditorContext]$context)
            Connect-Teamviewer
        }

However, if you were to just specify the function you may get some results you didn't expect.

Register-EditorCommand `
        -Name "Teamviewer.ConnectDevice" `
        -DisplayName "Connect to Teamviewer Device" `
        -SuppressOutput `
        -Function Connect-Teamviewer

In the above example, Connect-Teamviewer will be passed $context as a parameter when executed as an Editor Command.

function Connect-Teamviewer
{
    [Cmdletbinding()]
    param
    (
        [parameter(Mandatory=$true)]        
        [string]$ComputerName
    )

If your function looks something like the above code the command will actually error. $context will be passed to the $CompuerName parameter. Meaning you would need to write your functions with this in mind.

function Connect-Teamviewer
{
    [Cmdletbinding()]
    param
    (
        [parameter(Mandatory=$false)]        
        [[Microsoft.PowerShell.EditorServices.Extensions.EditorContext]]$Context,

        [parameter(Mandatory=$true)]        
        [string]$ComputerName
    )

This is likely not a good solution ether. It is going to be confusing to those writing their first commands, and there could potentially be some unwanted results. I have not tested it, but I wonder of the potential issues of a parameter not checking for a type and being passed context to do something like delete something.

function Delete-Stuff
{
    [Cmdletbinding()]
    param
    (     
        $Stuff
    )

    Process
    {
        foreach ($item in $Stuff) 
        { 
            Delete-AllTheThings $item 
        }
    }
}

One question I wanted to ask, could the information in $Context, be added to $psEditor? Is there a reason it has to be passed to the function @daviwil ?

$psEditor.context.cursorposition

Something along the lines of that. When I was first learning the Editor commands, this is sort of what I thought $psEditor was doing. I didn't realize there was a difference between $Context and $psEditor. @daviwil can you better explain the exact differences between the 2? I'd like to get a better grasp of exactly how each differ.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by tracing the Register-EditorCommand Function and ScriptBlock paths and comparing EditorContext with $psEditor; the issue names no files or tests. A maintainer decision is needed before implementation, with the desired behavior and completion checks documented.

Written by the indexing model from the issue text.

Assessment

Tech stack
powershell
Domain
developer-experience
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
20/100

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