Feature Request: use ERB instead of HAML

[olleolleolle]

TL;DR: This Issue is about using the preinstalled ERB instead of HAML for templating.

@mroderick and I are Rails Admin users. We'd volunteer to try to make this happen, provided this Issue is accepted.

Background

The landscape

• Rails Admin was created in a cultural moment when HAML was everywhere
• Time passed, HAML lost its dominance
• People have asked "Can we lose HAML?" before, and then was not the time
• Rails Admin 2.0 could have fewer opinions. Perhaps now is the time.

Reasons to allow people not to use HAML

• Users and maintainers get to have fewer gem dependencies
• New users won't have to learn HAML, everyone has to learn ERB

Solution proposal

• before 2.0, change all templates that come with Rails Admin to ERB
• have a tool-assisted workflow, to make this feasible
  • https://github.com/danchoi/herbalizer
• try to keep people's apps working, with their existing template overrides

Elsewhere

• https://thoughtbot.com/blog/fashion-runway-erb-vs-haml
• https://opensoul.org/2011/11/30/haml-the-unforgivable-sin/
• https://speakerdeck.com/klaustopher/erb

[Andrew-Max]

I'm actually dealing with this right now. One issue though is that herbalizer cannot fully convert this haml.

Sometimes it data attributes are passed to elements in a block and herbalizer cannot parse this.

[jasnow]

Does this help? https://haml2erb.org/

[mroderick]

Does this help? https://haml2erb.org/

herbalizer is the tool that powers that website

[RocKhalil]

I've opened this PR for this purpose: #3191

If you can help with the tests, it would be perfect 😃

[jcraigk]

HAML is dead but ERB is very suboptimal as a templating language in 2020. I suggest using Slim instead.