Turn PasteButton into keyboard shortcut

Question

I'm looking for a general "recipe" to do with a keyboard shortcut what I currently do with a PasteButton. Here is a working toy example PasteButton:

PasteButton[Subscript[Ω, \[SelectionPlaceholder]]]

It generates a capital Greek letter Omega (type in as \[CapitalOmega]) with a selection placeholder (black square) in the subscript.

To "keyboard-shortify" it, I know that I have to modify the file KeyEventTranslations.tr in

OS-dependent/Mathematica/11.0/SystemFiles/FrontEnd/TextResources/

but what I have to put into this file is a lot more complicated than just copying from how the PasteButton does it.

If I wanted just the Ω without the subscript, associated with the keyboard stroke Control-Shift-Command-O, I would have to put the following:

Item[
    KeyEvent["O", Modifiers -> {Control, Command, Shift}],
    FrontEndExecute[{
        FrontEnd`NotebookWrite[
            FrontEnd`InputNotebook[],
            "Ω",
            After
        ]
    }]
]

but what I tried putting into the .tr file with Subscript did not work - it always put Subscript[something] literally into the current notebook

I tried to write some code with SelectionMove[] and SelectionEvaluate[] and putting that into the .tr file, but it didn't work properly, and was awfully hard to test (restarting Mathematica all the time)

A more-than-ideal answer would be a function to which you supply, say, Subscript[Ω, \[SelectionPlaceholder]] as an argument, and which generates the string to be put into the .tr file as result.

Side question: Is there a way to test the code later being put into the .tr file without restarting Mathematica all the time?

Answer 1

Why not use an InputAutoReplacements instead? For example:

CurrentValue[EvaluationNotebook[], {InputAutoReplacements, "ww"}] = "Ω"

Then you can type: w w Control+- to enter the desired subscript.

If you really want to use KeyEventTranslations.tr to do this, then you need to enter boxes:

Item[KeyEvent["O", Modifiers -> {Control, Command, Shift}],
    FrontEndExecute[
        FrontEnd`NotebookWrite[
            FrontEnd`InputNotebook[],
            SubscriptBox["Ω", "\[SelectionPlaceholder]"],
            Placeholder
        ]
    ]
]