Apply a style to a selected structure

Question

If I type out, in my notes, a series of transformations, I often like to convert the very last step to a Framed equation:

I'm currently doing this by:

1. selecting the last expression,
2. copying it,
3. pasting it in a new field,
4. adding Framed[ … ] and evaluating,
5. copying the result,
6. pasting it back in the original field.

Is there a hotkey or quick way for me to apply a transformation to a selection, replacing it with the result? (Or something like that.)

Thanks!

Answer 1

Ctrl+Shift+Enter is the keyboard shortcut for "evaluate in place", which you press after highlighting an expression; this should ease your task. – J. M.♦ 2 mins ago

Notice I used Defer, it holds its arguments and is stripped when boxes are created. Exactly what we need keep e.g. 1 + 1 in this form.

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Answer 2

You could also use InputAliases. For example:

CurrentValue[EvaluationNotebook[], InputAliases] = {
    "fr" -> FrameBox[
        "\[SelectionPlaceholder]",
        BaselinePosition->Baseline,
        Background->LightGray
    ],
    ParentList
};

Here is a short animation using the alias:

Addendum

The nice thing about this approach compared to the accepted answer is that the added frame is transparent to the evaluation process. Here's an animation comparing the two approaches:

Explanation

One further comment. The difference between the two cases is that the evaluate in place approach used Framed, which by default has the option StripOnInput->False. Using:

10 == Framed[Defer[11-1], StripOnInput->True]

would produce a wrapper that is transparent to evaluation