Build tools in Elm

[eeue56]

Here's a crazy idea:

What if everything was written in Elm?

I mean, we already have

• Full client side support (JS, html, stylesheets)
• Server support (with node!)
• Database support (with node bindings!)

Why not go one more, and add build tools for Elm, in Elm too?

How do we do that? By abusing Elm, of course!

Firstly, there are some rules to make this work:

• Any Native code will be injected into the output file if the Native module is imported anywhere
• The Native code will be injected as found in the file
• Native code is bound before compiled Elm code
• timeouts make thing run later.
• ports get run by default if you include the file as Elm.worker(Elm.module)

With this in mind, it's pretty easy to make Elm output a file that can run itself. Or one that can run another file!

Add this little guy to the end of the Native module and watch what happens

setTimeout(function() {
    console.log("starting elm..");
    Elm.worker(Elm.Bootstrapper);
, 1000);

At the moment, this file will -

• Run itself
• Compile other modules
• Run the module it just compiled

In the real world, there's not really a case for this to be used. This is just here as an example - if you want an Elm project that can replace any other tool you have except for node, here's the guy to gun for.

[avh4]

FYI, here's an old tool I wrote that's half written in Elm: https://github.com/avh4/elm-compile-html

I think it would be great to make it easy to write command line tools in Elm.. I had a few ideas around that before starting on elm-format, but I haven't gotten back to them yet.

[eeue56]

This change makes it function and bootstrap like a standard node.js "binary" file, so it effectively a command line app. I also thought about considering a port of elm-format to Elm, but for speed reasons it probably makes sense to be in Haskell right now