[autumn-antlers]

This was once my understanding, and the accessibility argument still speaks to me, but I wish Elastic Tab-stops saw more discussion and support.

https://nick-gravgaard.com/elastic-tabstops/

I'll try to do my part.

I've been writing (and reading) a lot of Lisp lately, and have seen some projects adopt indentation idioms which offset blocks from the regular tab-stop intervals. A standard tab-stop might be +4, but then arguments might be lined up with each-other at +6 (+1.5 stops):

    (list 'a
          'b
          'c)

Any of those arguments could be forms, which might return to the standard tap-stop of +4 but off by 2 (let's call that `+4(+2)`):

    (list 'a
          (with-foo quz
              (bar quz))
          'c)

Lists written with the `quote` syntax might do the same thing, but produce an offset of only 1:

    '(a
      (b
       (c)))

The end result is that changing a code's indentation level (like when raising an anonymous function into a top-level definition) means adjusting the spaces (which were supposed to only be for alignment) if any preceding forms had introduced an offset. The alignment doesn't change, but it's relation to regular tab-stops does. Sometimes, this is an adjustment of zero, but you still need to think about it. In an all-spaces environment you could use vim's visual mode to select the block as a rectangle and paste it into the top level, but with "indent/align" semantics this same situation regularly requires maintenance (by inserting or removing spaces, in addition to manipulating indentation via tabs) to preserve both proper alignment and the integrity of the semantic distinction[1].

I think that elastic tab-stops fix this by correctly modeling indentation is it should be conceptualized, platonically divorced from the characters encoding it. I think that spaces are better than tabs when white-space isn't significant (and personal style might disregard tab-stops), but recognize that tabs are more accessible and worth using when tab-stops are enforced as a byproduct of significant white-space. I repeat that elastic tab-stops are awesome.

1: Someone correct me if vim can actually just do that with tabs just fine, i dont really know, it late~