Combine InputAlias with InputString to parse expressions from a string

Question

My knowledge of low-level notebook programming is very limited so I would be very grateful for any input regarding the following issue:

I would like to define an input alias (via InputAliases) that evaluates

parse[InputString[]]

in-place (like selecting it and then performing Menu → Evaluation → Evaluate in Place or Cmd + Return). The function parse will translate my textual input into an expression (and insert it at the current cursor position).

Currently, I am using the following alias,

SetOptions[EvaluationNotebook[],
    InputAliases->{"parse"->RowBox[{"parse","[","InputString","[","]","]"}]}]

and the workflow looks like this

1. ESC parse ESC to produce parse[InputString[]]
2. Press Ctrl + . a few times to select parse[InputString[]]
3. Evaluate in place via Cmd + Return
4. Type something into the input field and press Return

Basically, I would like to get rid of steps 2 and 3. I would appreciate any other solution if the desired behavior cannot be achieved using InputAliases. I would also be more than happy if an InputField could be used instead of InputString.

Answer 1

Success! Please evaluate the following code in a new notebook:

 Clear[eval];
 eval[cmd_] := Module[{nb},
    nb = InputNotebook[];
    NotebookWrite[nb, cmd, All];
    SelectionMove[nb, Previous, Cell];
    NotebookDelete[nb];
    SelectionMove[nb, Next, Cell];
    SelectionMove[nb, Next, Cell];
    Null];
 SetOptions[EvaluationNotebook[], 
   InputAliases -> {"eval" -> 
      RowBox[{"eval", "[", "\[SelectionPlaceholder]", "]"}]}];

Then follow this work flow:

1.-Press [ESC]eval[ESC]

2.-Write an operation, for example 2+2

3.-Press shift-enter

What actually happens is that a new input cell is written, and the old input cell is erased. I promise this is my last attempt ;)

Answer 2

You can do step 2 and 3 with one hotkey, by adding the item

Item[KeyEvent["u", Modifiers -> {Control}], 
    FrontEndExecute[
        FrontEndToken["ExpandSelection"];
        FrontEndToken["ExpandSelection"];
        FrontEnd`SelectionEvaluate[FrontEnd`InputNotebook[]]
    ]
]

to KeyEventTranslations.tr, located at the path that is the result of

FileNames["KeyEventTranslations.tr", $InstallationDirectory, 
  8] // First