Can I extend iex helpers?

I knew that aliasing would work but I swear I tried an import_file_if_available ".iex.exs" and that it failed to actually import a module defined in that .iexs.exs but indeed it does work great! Thank you!

> cat ~/.iex.exs
defmodule JaxIEx do
  def rr(opts \\ []), do: IEx.Helpers.recompile(opts)
end

import JaxIEx
import_file_if_available ".iex.exs"
[07:04:23] jason@Jasons-MacBook-Air /Users/jason/dev/password-validator
> cat .iex.exs
defmodule ProjIExUtils do
  def my_helper, do: IO.puts("hello, world")
end

import ProjIExUtils
[07:04:41] jason@Jasons-MacBook-Air /Users/jason/dev/password-validator
> iex --dot-iex ~/.iex.exs -S mix
Erlang/OTP 26 [erts-14.2.5.2] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit]

Interactive Elixir (1.17.2) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> rr
:noop
iex(2)> my_helper
hello, world
:ok
iex(3)>

Now if I update my i and s aliases to:

alias s='iex --dot-iex ~/.iex.exs -S mix phx.server'
alias i='iex --dot-iex ~/.iex.exs -S mix'

I can type rr instead of recompile

Looking at what import_file_if_available does, it’s just a macro that reads the file, parses it with Code.string_to_quoted and then spits it out. So I think it should make any aliases/imports available unless you’ve established a new scope. So just to confirm, this definitely doesn’t work when running with iex --dot-iex ~/.iex.exs?

# ~/.iex.exs

alias Example.One
alias Example.Two

import_file_if_available ".iex.exs"

Edit: I was just able to try this out and it does seem to be working for me, which is good news! So there must be something else going on, I think:

~/dev/lib_elixir main wip ⇡1                                                                                10:54:22 AM
❯ echo -n 'alias Example.One\nimport_file_if_available ".iex.exs"' > ~/.iex.exs

~/dev/lib_elixir main wip ⇡1                                                                                10:56:14 AM
❯ echo -n 'alias Example.Two' > .iex.exs

~/dev/lib_elixir main wip ⇡1 ?1                                                                             10:56:23 AM
❯ iex --dot-iex ~/.iex.exs
Erlang/OTP 27 [erts-15.0.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [jit:ns]

Interactive Elixir (1.17.2) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> One
Example.One
iex(2)> Two
Example.Two

This has been a great development! However I’m still struggling with one specific aspect.

If a given project defines it’s own .iex.exs that imports a module, is there a way that I can also have a ~/.iex.exs that imports a module? So far I haven’t been able to get that to work without both .iex.exs scripts from having knowledge of each other.

Things I’ve tried:

• I can use iex --dot-iex ~/.iex.exs to import my own .iex.exs, but then I don’t have a way to load the project-specific .iex.exs
  • If I load it with Code.eval_file(".iex.exs") then any imports it defines are not available
  • If I load it with import_file_if_available(".iex.exs") then any imports it defines is not available

The only workaround I have so far is for my ~/.iex.exs to have knowledge of the name of all modules that any of the project-specific .iex.exs wants to import and import them all if they exist.

In Elixir v1.14+ you will be able to import the module as you define it in .iex.exs files, as we now evaluate it line by line: Evaluate --dot-iex line by line · elixir-lang/elixir@395b053 · GitHub

Ah, ok. I’ll just define the helper somewhere else then.

Unfortunately, no, because it is not possible to import a module in the same file as in which it was defined: you will get above compile error scenario.

Is there an easy way to define an IEx helper now? I’d prefer to keep the helper definition inside .iex.exs if possible.

That works

Thanks @andy !

You need to start iex with the -pa option to append your home dir to the iex search path. Try iex -pa ~/

Also FYI you can use import_if_available - prevents the error message if the module is not found.

Doesn’t work for me unfortunately.

I have the Elixir.IEXHelper.beam file in my home folder and in
.iex.ex I have
import IEXHelper
I get
** (CompileError) /Users/chazsconi/.iex.exs:1: module IEXHelper is not loaded and could not be found

Any suggestions for how to fix this?