Behind the Scenes

As we warned in the beginning, there's a lot going on behind the scenes: in rebar3 as well as LFE and Erlang (we haven't even touched OTP here ...!). This guide just gives you a quick taste of the LFE flavour :-) Before parting ways, though, there are some more bits we should share.

Some of those things are hinted at when just checking the current versions you are running using the LFE plugin's versions command (from a terminal where you have cded into your project directory):

rebar3 lfe versions

(#(apps (#(my-test-lib git)))
 #(languages
   (#(lfe "1.3-dev")
    #(erlang "23")
    #(emulator "11.0.2")
    #(driver_version "3.3")))
 #(tooling (#(rebar "3.10.0") #(rebar3_lfe "0.2.0"))))

To give a sense of what you'll encounter in the future: very often Erlang, LFE, and other BEAM language apps include more than just themselves when they are shipped. For instance, if you're in the REPL and you type (regs) you will see a list of applications that have been registered by name, currently running in support of the REPL. Usually, each app will have its own version. There is an LFE blog series on such things, showing you how to create and mess around with different types of LFE apps.

The LFE rebar3 plugin will also help you create OTP apps in LFE and perform other key tasks you may wish to integrate into your development workflow. You can learn more about those in the plugin's Command Reference

Next Stop

Where to go from here ...