Formatting changes line endings to just LF (`\n`)

[mbartlett21]

It would be good to have gren format leave the line endings as is, preserving CRLF (\r\n) newlines, rather than changing them all to just LF (\n).

Notes:

• How should this interact with --validate?

Related to #42.

[avh4]

Possible options here:

• Do nothing. Interestingly, for elm-format, no one's really complained about this. (discussion) Folks noted there that git's default setting for core.autocrlf usually solves the problem for them.
• Have a command-line option that will cause gren format to always output CRLF (and expect CRLF when validating).
• Auto-detect the line endings either by adding some kind of tracking in the parser (seems complicated), or by doing a second parsing pass to check for newline format. I guess there's also be a question of how to handle the case when both types of line endings are found.

And to simplify a little bit, LF seems to be the most common, with CRLF still sometimes used on Windows. CR seems to only have been used on MacOS prior to 2001, so imo there's not much need to support it now.

Also of note, I believe this feature would only be relevant to Windows-only development teams. Teams that have a mix of Windows and Mac/Linux workstations usually seem to want to standardize on LF.

[robinheghan]

1. core.autocrlf would only work if you're using git though, right?
2. I think this is reasonable. I assume it would be bad to force crlf if the compiling platform is Windows?
3. In the case where both types of line endings are found, I'd lean towards forcing one. Which one, though... 🤷‍♂️

@mbartlett21 would adding a --crlf flag (or similar) be an acceptable solution for your use case?

[mbartlett21]

would adding a --crlf flag (or similar) be an acceptable solution for your use case?

@robinheghan That would work well for me.