Edit PowerShell console input in external editor

EditConsoleInput.ps1

#---------------------------------------------------------------------------------------------------------------
# Defines keyboard shortcut Alt+E for the console to edit current input in VSCode
# (edit the line that starts with "code" to use another editor).
#
# This code is an extension of this StackOverflow answer:
# https://stackoverflow.com/a/71175083/7571258
#
# New features:
# - Saves/restores the current cursor position (if the text hasn't changed too much).
# - Passes the current cursor position to VSCode, so the editors cursor gets positioned as in the console.
# - While editing, show a console message to remind the user why this console is currently blocked
#   (remove the Write-Progress lines to disable this feature).
# - After editor has been closed, bring console window to foreground again (only on Windows and MacOS platform).
#
# When this code is put into the $Profile file, all new PowerShell console windows have Alt+E available.
#
# Special thanks to StackOverflow user mklement0 (https://stackoverflow.com/users/45375/mklement0) for
# providing many tipps to improve this code. Also see his alternative solution that uses
# built-in (but currently somewhat limited) way of PowerShell to edit console input in an external editor:
# https://stackoverflow.com/a/71181105/7571258
#---------------------------------------------------------------------------------------------------------------

function ConvertTo-LineAndChar {
    <#
    .SYNOPSIS
        Convert cursor position (offset) to line number and character index 
    #>    
    [CmdletBinding()]
    param(
        [Parameter()] [string[]] $lines, 
        [Parameter(Mandatory)] [int] $cursorPos     
    )

    if( $lines ) {
        $pos = $nextPos = 0

        for( $i = 0; $i -lt $lines.Count; $i++ ){ 

            $nextPos = $pos + $lines[ $i ].Length + 1
            
            if( $nextPos -gt $cursorPos ) {
                return [PSCustomObject]@{ line = $i; char = $cursorPos - $pos }
            }
            
            $pos = $nextPos
        }
    }

    [PSCustomObject]@{ line = 0; char = 0 }  # default output
}

#---------------------------------------------------------------------------------------

function ConvertTo-CursorPos {
    <#
    .SYNOPSIS
        Convert line and char index to cursor position (offset) 
    #>
    [CmdletBinding()]
    param (
        [Parameter()] [string[]] $lines, 
        [Parameter(Mandatory)] [int] $nLine,     
        [Parameter(Mandatory)] [int] $nChar    
    )

    if( -not $lines ) {
        return 0
    }

    $nLine = [Math]::Min( $nLine, $lines.Count - 1 )
    $pos = 0

    for( $i = 0; $i -lt $nLine; $i++ ){     
        $pos += $lines[ $i ].Length + 1
    }

    # Output
    $pos + [Math]::Min( $nChar, $lines[ $nLine ].Length )
}

#---------------------------------------------------------------------------------------
# Define keyboard shortcut Alt+E to edit the current console line in VSCode

Set-PSReadLineKeyHandler -Chord "Alt+e" -ScriptBlock {

    $currentInput = $null
    [int] $cursorPos = 0

    # Copy current command-line input and get cursor position
    [Microsoft.PowerShell.PSConsoleReadLine]::GetBufferState([ref] $currentInput, [ref] $cursorPos)

    # Save current command-line to temp file
    $tempFileName = "ps_$PID.ps1"
    $tempFilePath = Join-Path ([IO.Path]::GetTempPath()) $tempFileName
    Set-Content $tempFilePath -Value $currentInput -Encoding utf8

    # Convert cursor position to line and char index 
    $currentInputLines = @($currentInput -split '\r?\n')
    $goto = ConvertTo-LineAndChar -lines $currentInputLines -cursorPos $cursorPos

    # Show a message to remind the user why this console is currently blocked
    Write-Progress -Activity 'External editing in progress' -Status "Close VSCode ($tempFileName) to continue working in this console" -PercentComplete -1

    # Edit the command using VSCode (passing the cursor position to the editor) 
    code --new-window --wait --goto "${tempFilePath}:$($goto.line + 1):$($goto.char + 1)"

    # Remove the message
    Write-Progress -Activity 'External editing in progress' -Completed

    # Get the edited input as individual lines
    $editedInputLines = Get-Content -LiteralPath $tempFilePath -Encoding utf8 

    # Cleanup
    Remove-Item $tempFilePath

    # The console always uses LF character as line separator, regardless of platform. 
    $editedInput = ($editedInputLines -join "`n").Trim()

    # Replace current console line with the content of the temp file
    [Microsoft.PowerShell.PSConsoleReadLine]::Replace(0, $currentInput.Length, $editedInput)

    # Try to restore cursor position (if text hasn't changed too much)
    $cursorPos = ConvertTo-CursorPos -lines $editedInputLines -nLine $goto.line -nChar $goto.char 
    [Microsoft.PowerShell.PSConsoleReadLine]::SetCursorPosition( $cursorPos )

    # Bring console window to foreground again
    if( $env:OS -eq 'Windows_NT' ) {   
        (New-Object -ComObject WScript.Shell).AppActivate( $PID ) 
    } 
    elseif( $IsMacOS ) {   
        $terminalAppName = $env:TERM_PROGRAM  
        if( $terminalAppName -eq 'Apple_Terminal' ) { 
            $terminalAppName = 'Terminal.app' 
        }
        $PSNativeCommandArgumentPassing = 'Legacy'   
        osascript -e "tell application \""$terminalAppName\"" to activate" 2>$null 
    }

    # Uncomment this to automatically press "Enter" key in the console after editing.
    #[Microsoft.PowerShell.PSConsoleReadLine]::AcceptLine()
}

I appreciate the shout-out in the comments, @zett42.

Having just revisited this:

• (New-Object -ComObject WScript.Shell).AppActivate( $PID ) isn't strictly needed on Windows (the terminal re-activation problem seemingly only affects macOS), but - perhaps more importantly:

  • On Windows it would only be a courtesy feature, namely to ensure that the terminal is also returned to if the user happened to switch to another application - such as a web browser to perform a search.
  • However:
    • fundamentally, it can only work if stealing focus is enabled for processes that do not have the input focus, which is not enabled by default, and only enabled implicitly if you have applications such as AHK (AutoHotKey) installed and running
    • situationally, it wouldn't work when PowerShell runs in Windows Terminal, where PowerShell doesn't own the terminal window.

• PowerShell/PowerShell#21525 (comment) is a follow-up discussion that may be of interest.