Rhombus v1.0 - Hackdot

Re:Rhombus v1.0 by rmunn on Wednesday June 24, 2026 @06:20AM (#48657678)

It depends on the language's indentation requirements. That can work in Python, where you never need to line things up with characters above that aren't a multiple of an indent level. But in F#, at least a few years ago when I tried it, there are times when you would need (or strongly want) to line things up with other characters. For example, this example from https://learn.microsoft.com/en-us/dotnet/fsharp/style-guide/...:

    functionName
        arg1
        arg2
        arg3
        (function
         | Choice1of2 x -> 1
         | Choice2of2 y -> 2)

Note how the | needs one extra space in order to line up with the word "function", due to the open parenthesis. If you're using tabs for indentation, that means you need a series of tabs plus one trailing space after the tabs, in order to line up the | correctly.

Any situation where you must have a mixture of tabs and spaces for code to work right leads to a nightmare. Because it makes you have to turn on visible whitespace in your editor and peer closely at the lines. I have a simple rule: "Do NOT make me care whether there are tabs or spaces in this file!" If it's significant whether a line is indented with a tab or space, then that rule is broken, and you're probably in for a bad time. (Case in point: Makefile syntax).

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Re:Rhombus v1.0 by adrian_b on Wednesday June 24, 2026 @08:26AM (#48658670)

I did not take this in consideration, because for such code, with brackets and separators, I prefer to align the separators with the opening and closing brackets, like this:

  ( ...
  | ...
  | ...
  | ...
  )

  { ...
  ; ...
  ; ...
  ; ...
  }

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Re:Rhombus v1.0 by rmunn on Wednesday June 24, 2026 @01:52PM (#48663399)

I just checked, and lining up the | with the open parentheses does work in modern F#. I believe they revamped the indentation rules a few years back, because I definitely remember things like that not working back when. So perhaps now your idea would be feasible. However, there was definitely a time in the past when F#'s indentation rules would have been problematic for tabs, and that fact is why the F# compiler still forbids tab characters outside of string literals or comments. (And there are still indentation styles recommended, though not required, by the official F# style guidelines that would require the use of spaces. Which is another reason to avoid tabs in F# code, because they're less flexible than spaces. Usually the reason to prefer tabs is because they're more flexible, but the slightly-peculiar nature of F#'s indentation rules means tabs are less flexible in F# code.)

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