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Is it possible to program the Front End to automatically format double square brackets without having to type Esc[[Esc each time? It's awful to have to type Esc four times for each Part expression, and even more annoying to visually parse the unformatted double brackets.

See also this entry in MathGroup archive: adding a keyboard shortcut for double brackets

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3  
I edited the KeyEventTranslations.tr file to add my own shortcuts. –  Silvia May 6 '12 at 2:00
    
Thanks Silvia, could you provide details please? –  alancalvitti May 6 '12 at 2:04
    
Assuming you are under win, open the file in a text editor, add a line like Item[KeyEvent["[", Modifiers -> {Control}],FrontEndExecute[{FrontEnd`NotebookWrite[FrontEnd`InputNotebook[],"[L‌​eftDoubleBracket]", After]}]] –  Silvia May 6 '12 at 2:13

2 Answers 2

up vote 29 down vote accepted

Some approaches are discussed in this question on StackOverflow. Original references to these go to Szabolcs's webpage and a MathGroup posting by Mr.Wizard.

To summarize, you copy the file: $InstallationDirectory/SystemFiles/FrontEnd/TextResources/Macintosh/KeyEventTranslations.tr to $UserBaseDirectory/ (with the same directory tree) and add the following modifications after EventTranslations[{ in the file:

Item[KeyEvent["[", Modifiers -> {Control}],
        FrontEndExecute[{
            FrontEnd`NotebookWrite[FrontEnd`InputNotebook[],
                "\[LeftDoubleBracket]", After]
        }]],
Item[KeyEvent["]", Modifiers -> {Control}],
        FrontEndExecute[{
            FrontEnd`NotebookWrite[FrontEnd`InputNotebook[],
                "\[RightDoubleBracket]", After]
        }]], 
Item[KeyEvent["]", Modifiers -> {Control, Command}],
        FrontEndExecute[{
            FrontEnd`NotebookWrite[FrontEnd`InputNotebook[],
                "\[LeftDoubleBracket]", After],
            FrontEnd`NotebookWrite[FrontEnd`InputNotebook[],
                "\[RightDoubleBracket]", Before]
        }]], 

These provide the following shortcuts:

  • using Ctrl+[
  • using Ctrl+]
  • 〚〛 using Ctrl+Cmd+]

Replace Command with Alt for Windows/Linux and modify the paths above accordingly.

You can also try Andrew Moylan's suggestion, in the same post, but I haven't tried it.

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this is a nice trick, however I couldn't get it to work on a German keyboard. Since the [ and ] keys events are generated by pressing Alt-Gr 8 and Alt-Gr 9 it seems Mathematica does not catch the KeyEvent correctly. Switching over to EN keyboard design works however... Any ideas how to capture Alt-Gr? –  Rainer Oct 27 '13 at 10:54
    
Just a note, copy and edit the file at "\$UserBaseDirectory" doesn't seem to be working for me. But it works if I modify the file directly in the path "\$InstallationDirectory/SystemFiles/FrontEnd/TextResources/Macintosh/KeyEventTr‌​anslations.tr". –  xslittlegrass May 13 at 0:15
    
@xslittlegrass It's not a good idea to modify those files, as they can be overwritten by a new version (if you're in the habit of just having the current version). There might be something else going on with your setup if the above doesn't work. –  rm -rf May 13 at 0:38
    
@rm-rf Yes, actually that's why I post a comment here :) Today I reinstalled Mathematica, and it stops working. I have to lookup this post and edit the file again to make it work. And it took me a while to remember that I have to edit the file in place to make it work for my computer. –  xslittlegrass May 13 at 1:36
    
On my Windows 7 (64 bit) computer using Mathematica 9.0.0.0, I did not need to replace Command with Alt. The code works as written without modification. –  Carl Morris Aug 12 at 20:49

Edit the KeyEventTranslations.tr file in a plain text editor by adding the following definitions to the first section of the file:

EventTranslations[{

(* Custom shortcuts *)
Item[KeyEvent["[",Modifiers->{Control}],
    FrontEndExecute[{FrontEnd`NotebookWrite[FrontEnd`InputNotebook[],
    "[\[SelectionPlaceholder]]"],FrontEndToken["MovePreviousPlaceHolder"]}]],

Item[KeyEvent["]",Modifiers->{Control}],
    FrontEndExecute[{FrontEnd`NotebookWrite[FrontEnd`InputNotebook[],
    "\[LeftDoubleBracket]\[SelectionPlaceholder]\[RightDoubleBracket]"],
    FrontEndToken["MovePreviousPlaceHolder"],FrontEndToken["MovePreviousPlaceHolder"]}]],

(* Evaluation *)

Note that these shortcuts are set up to use the "Control" modifier to insert a template for pairs of single/double brackets.

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