Hi,
Inspired by "oclua" I started to make an own on-calc lua editor and finished the first version of it in summer 2013. It had many flaws and lacked some important features, so I decided to make a second, vastly improved version of it:

Features:
- Fully functioning code editor on page 1.1
  - Monospaced characters
  - Syntax highlighting (customizable)
  - Autocompletion menu: basic lua functions, nspire api function, global script variables, custom items
  - Undo/redo actions
  - Select code to copy, cut, paste, etc.
  - Find function
  - Save & load infinite amount of scripts with length each up to 1.7 million characters
  - Hotkeys for special characters
  - Full support for UTF8-encoded unicode characters
  - Import code from librarys and saved scripts
  - Autosave function
  - Customizable color-set
  - Customizable font

- Entirely crash protected live testing on page 1.2
  - Nearly no restrictions
  - Full support of event handlers using "on"s metatable
  - Resets global environment after each build
  - Pause/Unpause scripts
  - Full module (physics & colors) support
  - Calls all initialization event handlers
  - Full support of 2DEditors

- Console
  - Logs "print" outputs, errors and status logs of the editor
  - Can be deleted, copy&pasted and resized with Nspires layout options
  - Commands can be entered to execute them during live-testing a script

- Shortened portable version of the Nspire api reference guide on page 2.1
- Shortened portable version of the lua reference manual & chipmunk physics api guide on page 2.2

- Compatible to:
  - OS 3.1 and OS>3.1
  - Greyscale models
  - Clickpad models
  - Desktop
  - iPad



Current Version: 2.2.1
Current Size: 73KB

The attached zip file contains the editor files for OS 3.1 and OS>3.1, controls pictures of both Nspire layouts and a readme.txt

Bug reports are welcome!   

wait, we get to program lua on-calc? AWESOME!

@Jonius7:
1.) No, I didn't know that... LuaCS looks better than mine, but there's no actual error handling and oclua keeps crashing as it has always done. Also you only can save 1 program. Also characters like [] and {} and : are as tedious to type as they were in the "Notes" App.
2.) The image is edited; there aren't really "[]" and "{}" Buttons, I redefined following buttons: "e^x"==>"["; "10^x"==>"]"; "ln("==>"{"; "log("==>"}"; "(-)"==>":"
It's very handy like this on the touchpad layout. I'll implement a feature to swap the layout, maybe the "cos" and "tan" buttons for "[" and "]" and the "^-1" versions for "{" and "}"? Unfortunately I don't know anyone with a clickpad nspire to try it out

I think yours looks quite good. Maybe because you're using "serif" font instead of "sansserif" which I think the other ones use.

Also I have a clickpad, but I used kArmTI (nspire_emu with extra features, I recommend it) to test the clickpad, it can handle all the main 6 editions of TI-nspire.

This looks really nice. I especially like the not-crashing-on-error part This drives me to get back to Lua programming again now that it's portable once more. I hope you stick with the project.

@Jonius7: nspire
1.) Thanks for your the hint for the emulator, but I don't get it to work: everytime I try to start "nspire_emu.exe" a black window flashes once and nothing else happenes
2.) I haven't made an update yet, because I don't get the emulator to work But those button rebinds are already in the current version.
3.) BIG thanks for that reference to nSpaint!!! Now I don't have to do that; Chockosta wrote ~2200 lines of code for that! I'll ask him for permission for integration or I'll just put a note somewhere...

UPDATE!
Version 0.1.1 now attached on the first post

New features:
- math button input get converted to lua code (like the root or the pi button)
- better visuals on greyscale displays
- support for clickpad layout (switch in the menu) explanation in the "Controls" spoiler of the first post
- settings will be saved now

@lkj: Thanks for the link! I'll test now what I just updated on the emulator