Rescript-compiler: Make `bsb --init .` work

[bsansouci]

It'd be nice to be able to do bsb --init . and have bsb simply add a bsconfig.json.

This would help adopting bsb on existent projects.

Right now that'll error if you already have a src folder for example. It'l also error if you've install bsb locally.

[nickzuber]

It looks like bsb -init is designed to set up a template project instead of prepping an existing project to interop with Reason.

$ bsb --help
-init  Init sample project to get started. Note (`bsb -init sample` will create a sample project while `bsb -init .` will reuse current directory)

I think having init create a template makes sense and has its place, perhaps there could be a separate command for adding config files and dependencies to an existing project so we don't confuse the two -- maybe something like -setup?

[bobzhang]

relevant to #2498

Right now that'll error if you already have a src folder for example.

Shall we scan the directory? what's the expected behavior? Note currently if it is an empty directory, it should work

[bsansouci]

Based on @nickzuber's really cool tool add-reason, here's what seems to be the simplest setup without being too magical. When one calls bsb --init . we check if there's a package.json or not.

If there's a package.json:

• add a bsconfig.json
• add src/reason/index.re (with the necessary folders if not there)
• conditionally symlink the global bsb if bsb was installed globally. Right now bsb will error when it's already installed locally. I'd propose simply checking if there's already something called node_modules/bs-platform there.
  This should allow the same const reason = require("src/reason") easy require.

If there isn't a package.json simply do what we currently do with bsb --init projectName but in the current dir.

If the user does bsb --init projectName we do the same as we currently do.

I think this would bring the easy setup from add-reason directly into bsb with little added complexity :)

[nickzuber]

Thanks for the outline @bsansouci, I think this looks really good so far.

Do you think the config file should default to in-source compilation w/ .bs.js suffix (this would be outlined clearly in docs if so)? I think these options produce the least amount of interop friction personally, but would like to hear other thoughts.

I'd love to take this task on too 😄

Edit: I'm currently working on this!

[mgmarlow]

It would also be nice to be able to call --init on a directory that already exists. With the @angular/cli I can create an empty repo on github with readme and license, clone it, (git clone http://.../blog) and call ng new blog and it will fill in the files in the directory that already exists.

Doing this w/ reason results in:

blog already existed

[nickzuber]

@mgmarlow Is there any reason you can't cd into the directory and then call bsb -init . (after this change is made)? Or is it just for the sake of convenience?

[bobzhang]

Done in master, it will try to add new files and if it is already there, it will ignore