Have Button fire with both Kernel and FrontEnd

Question

Here's some code which, when evaluated, types an expression in the cell below it:

FrontEndExecute@FrontEnd`SelectionMove[SelectedNotebook[],Next,CellContents];[email protected];
FrontEndExecute@FrontEnd`NotebookWrite[SelectedNotebook[],"1"];[email protected];
FrontEndExecute@FrontEnd`NotebookWrite[SelectedNotebook[],"+"]; [email protected];
FrontEndExecute@FrontEnd`NotebookWrite[SelectedNotebook[],"2"];[email protected];
FrontEndExecute@FrontEnd`SelectionMove[SelectedNotebook[],All,CellContents];[email protected];
FrontEndExecute@FrontEnd`NotebookApply[SelectedNotebook[],
  FractionBox["\[SelectionPlaceholder]","\[Placeholder]"]];[email protected];
FrontEndExecute@FrontEnd`NotebookWrite[SelectedNotebook[], "3"];

Now I want to put it in a button, so I'll wrap it in Button["type stuff",...]. But then it takes more than a second to see the full output due to something about the front end and updates and kernels and what not.

If instead I write Button["type stuff",...,Evaluator->None], I find out that Pause is not a function available to the front end.

If I strip out all the Pauses, then it works great -- there is some delay -- I would just like to slow it down.

Question

Is there a function available with no Evaluator that can slow it down? Is there a way to switch Evaluators while a Button function is running? Or should I stick with kernel evaluation only and do something with Dynamic to get the progressive typing?

---

Extraneous questions:

• I tried to store the big typing code in a symbol, using HoldForm and ReleaseHold in the Button -- I didn't manage to get it right, the front end couldn't ReleaseHold the thing
• I tried to have a wait parameter t instead of .2, but again the front end couldn't reference the value of t, and I couldn't figure out how to inject t with a Block or something before creating the Button
• I tried to generate the code with a Riffle[.../@Characters@"1+2",[email protected]], but how to turn the resulting list into an "input expression" -- no, an "input cell" with some newlines -- no, an Inactive@CompoundExpression@@..., but how to Activate it without evaluating it... I'm at a loss.

Answer 1

Is this what you are looking for?

typeStuff = 
  Module[{}, 
   Hold[FrontEndExecute@
     FrontEnd`SelectionMove[SelectedNotebook[], Next, CellContents]; 
    [email protected];
    FrontEndExecute@FrontEnd`NotebookWrite[SelectedNotebook[], "1"]; 
    [email protected];
    FrontEndExecute@FrontEnd`NotebookWrite[SelectedNotebook[], "+"]; 
    [email protected];
    FrontEndExecute@FrontEnd`NotebookWrite[SelectedNotebook[], "2"]; 
    [email protected];
    FrontEndExecute@
     FrontEnd`SelectionMove[SelectedNotebook[], All, CellContents]; 
    [email protected];
    FrontEndExecute@
     FrontEnd`NotebookApply[SelectedNotebook[], 
      FractionBox["\[SelectionPlaceholder]", "\[Placeholder]"]]; 
    [email protected];
    FrontEndExecute@
     FrontEnd`NotebookWrite[SelectedNotebook[], "3"];]];

Button["ClickMe", ReleaseHold@typeStuff, Method -> "Queued"]