Enable tab key to input four spaces and implement an overwrite mode

[doersino]

It would be neat if pressing the tab key inserted four spaces. Related Stack Overflow thread: https://stackoverflow.com/questions/6637341/use-tab-to-indent-in-textarea

Additionally, an overwrite mode (where typing overwrites the character right of the caret instead of inserting a character at the caret position) would be handy.

So would be a way of automatically inserting spaces between the last non-space character of each line and the right edge of the textarea. But this is probably fraught with problems (when the user resizes the window, or when long lines that must wrap [which is a visual issue as things are, anyway] are present, etc.).

Addressing these three points would leave the diagram drafting board feature-complete, as far as I'm concerned. (Perhaps a tiny pop-up "syntax" reference linked from the sidebar wouldn't hurt, either.)

If anyone would like to tackle these issues, please get in touch!

[doersino]

Come to think of it (a year and a half later), it'd be best to rely on a widely-used text editor library instead of rolling my own. Something like ASCIIFlow perhaps, which is <canvas>-based – not ideal, but perhaps a prudent choice (I think the background grid is an excellent idea, by the way). Not sure if I'll work towards closing this issue anytime soon, though.