Formatter: consider using tabs instead of spaces

[giacomocavalieri]

From time to time someone in the Gleam Discord suggests the formatter could use tabs instead of spaces for accessibility reasons.

A couple of things that have emerged so far:

• The formatter won't ever be configurable, so it's not a choice to make it opt-in. Either we always use tabs or we always use 2 spaces
• People bring up accessibility as a point in favour of using tabs as one might have a bit of trouble reading code that uses two-space indentation
• However, GitHub displays tabs as 8 spaces by default. That can be configured to use less space but it would probably look bad to the average user who's reading Gleam code on GitHub and we'd like to avoid it

I've opened this discussion so people can chime in here if they have anything to add or any experience they'd like to share :)

[lpil]

Do we have any information on the accessibility concerns relating to tabs and spaces?

[giacomocavalieri]

I don't personally, when it's brought up I see people sharing links like the ones in this question https://discord.com/channels/768594524158427167/1286540015274561576/1286540015274561576

[lpil]

Thank you. Some of these are very compelling.

[lpil]

The downside to this is an increase in perceived strangeness of Gleam. Tabs are unpopular and 8 space tabs even more so, so adopting these will result in fewer people deciding to try Gleam, hurting our growth.

Is there anything we can do to avoid GitHub etc showing Gleam with 8 space tabs?

[giacomocavalieri]

There's a couple of ways:

• it can be configured on your own account, this is not up to us and I don't expect many people to know this https://docs.github.com/en/account-and-profile/setting-up-and-managing-your-personal-account-on-github/managing-user-account-settings/managing-your-tab-size-rendering-preference
• it can be configured by appending something to a GitHub's url, even more obscure than the other one https://stackoverflow.com/a/23522945/19214823
• add an .editorconfig to every repo setting the tab size to 2. This is something gleam new could take care of but wouldn't work for older projects and I'm not a huge fan of having yet another configuration file

If GitHub were to use a 2/4 spaces default for tabs it would be way easier to push for a switch 🥲

[lpil]

1 and 2 are not options as we cannot control what settings people use, and we cannot modify all links to GitHub.

It would be annoying to have an additional config file but seems 3 could work. Are there any accessibility implications of using this config file? Does it prevent them from getting the tab size they want?

[giacomocavalieri]

I haven't really looked into so I'm not sure. I think it will depend on how any specific editor handles it

[mpldr]

Hi, just wanted to chime in that I am one of the people for whom this accessibility is a thing. 2-space indents makes it nigh-impossible to me to separate scopes. In space-obligatory languages I will use 8 space indents which (as was already pointed out) is a bad choice for many people and tabs are the only solution I know of to address this in a flexible enough way.

As for the specifics, I would recommned trying to reformat some larger codebases and identify issues that look weird (sometimes a few linebreaks might be a better way)

As for "legacy-support" I see a relatively simple option:

• use editorconfig as the marker. If it has *.gleam: indent_style = tab, its new one
• otherwise use "legacy-mode"

While not a great fan of keeping two modes around, I think the value of tabs is worth it. I am biased though, I will freely admit that.

TL;DR: I have yet to find a case where indentation with tabs and aligning with spaces does not work as well, if not better than space-indentation. Also +1 for editorconfig.

[nhcoding4]

Allowing an option in the gleam.toml file would be cool so that people who prefer tabs > spacing . Something like spacing="tab" .

[GearsDatapacks]

The formatter is not configurable by design. That's unlikely to change