Can we automatically convert tabs to spaces when users input code?

Question

Obviously this is personal preference when you're creating code on your own machine. However, since adding tabs to a text box is not (as far as I know) natively supported in most browsers. Three or four spaces would make editing/formatting questions and answers easier. This wouldn't need to be done on paste (though that would be nifty), but could be done at question/answer save time. Is something like that feasible?

For example:

    Two tabs
    Eight spaces

Appears in the editor like:

Which makes it annoying for lining up things for formatting. Maybe this is just nit-picky, but it would be nice to have some consistency.

EDIT

Allow me to make this clearer, there seems to be some confusion.

I clearly agree that mixing tabs and spaces is bad. This post is advocating for not having both. Since browsers typically only allow spaces as input, I'm saying we should automatically switch to spaces. Otherwise, if you want to edit code that's been pasted in with tabs, you can only add spaces, therefore mixing tabs and spaces. If the editor converted tabs to spaces, we'd never have mixed tabs and spaces.

Answer 1

I like the initial idea, but at the same time. I am going to play some "devil's advocate".

first the system would have to know the difference between code, and text upon insert, and the system does not know this until after the tags have been processed (which for many users myself included not even entered until after the question has been written/copied) so the system would have to know what code looks like.

the only way to implement this cleanly would probably require users to use XML/HTML tags for example: (not that [ is equivalent to <, and ] is equivalent to > )

[Code]

//paste code here, and have tabs converted to 4 spaces

[/Code]

which are valid tags, but some users myself included don't use them, and just want to be able to paste in code, and have this kind of functionality there

the other thing that I could see is for those users that purposely format their code with tabs for spacing of comments to the right of code test (for clarity/explanation)

TYPE varName        // this var does ______

so that it is not confused as part of the code line just in case color formatting doesn't like it, and say that I just wanted 2 slashes.

but on the other hand I really would like something like this, and would appreciate it being implemented across all stackExchange sites, and probably the metas as well (code sometimes ends up on the meta sites)

Answer 2

Correct me if I'm wrong, but the user doesn't currently have control over the number of spaces used to represent a tab character in their code? Does Markdown assume exactly 4 spaces per tab, always? If someone has written code with an indent-width of 2 but with spaces instead of tabs in their code, does the system handle that properly?

Indenting is the easier of the two cases, because regardless of the tab width, the indents will look 'right'. But for mid-line tabs, you're mixing single characters with the tabs, and unless they happen to use the same tab width as the site / browser, then regardless of whether they're kept as tabs or converted to spaces, mid-line tabs will not line up correctly, without the ability to set tab width on a block by block basis, it probably won't look right.

I'd say converting tabs to spaces on pasting (or at some other convenient point) has definite merit, but I think it would have either have to be a) an optional feature, or b) allow setting what the tab width actually is. Otherwise people with a tab-width other than 4 are going to be continually annoyed that their code is being 'fixed' to use a different tab width, and not giving them the option to keep the tabs they wrote it with.