Add --dot-iex command line option to IEx

It allows one to override the standard locations where .iex is searched
and also makes it possible to disable .iex loading completely.

Author: alco

bin/iex

@@ -14,6 +14,8 @@ if [ $# -gt 0 ] && ([ $1 = "--help" ] || [ $1 = "-h" ]); then
   --name \"name\"     Makes and assigns a name to the distributed node
   --sname \"name\"    Makes and assigns a short name to the distributed node
   --remsh \"name\"    Connects to a node using a remote shell
+  --dot-iex \"path\"  Overrides default .iex file and uses path instead;
+                    path can be empty, then no file will be loaded
 
 ** Options marked with (*) can be given more than once
 ** Options given after the .exs file or -- are passed down to the executed code
@@ -33,4 +35,4 @@ readlink_f () {
 
 SELF=$(readlink_f "$0")
 SCRIPT_PATH=$(dirname "$SELF")
-ELIXIR_NO_CLI=1 exec "$SCRIPT_PATH"/elixir --no-halt --erl "-user Elixir-IEx-CLI" +iex "$@"
+ELIXIR_NO_CLI=1 exec "$SCRIPT_PATH"/elixir --no-halt --erl "-user Elixir-IEx-CLI" +iex "$@"

lib/elixir/lib/kernel/cli.ex

@@ -222,6 +222,12 @@ defmodule Kernel.CLI do
     { config, t }
   end
 
+  # This clause is here so that Kernel.CLI does not error out with "unknown
+  # option"
+  defp process_iex(["--dot-iex",_|t], config) do
+    process_iex t, config
+  end
+
   defp process_iex([opt,_|t], config) when opt in ["--remsh"] do
     process_iex t, config
   end

lib/iex/lib/iex.ex

@@ -1,5 +1,5 @@
 defrecord IEx.Config, binding: nil, cache: '', counter: 1, scope: nil,
-                      result: nil, load_dot_iex: true
+                      result: nil, dot_iex_path: nil
 
 defmodule IEx do
   @moduledoc %B"""
@@ -87,6 +87,9 @@ defmodule IEx do
       iex(1)> value
       13
 
+  It is possible to override the default loading sequence for .iex file by
+  supplying the --dot-iex option to iex. See `iex --help`.
+
   ## Expressions in IEx
 
   As an interactive shell, IEx evalutes expressions. This has some
@@ -206,7 +209,7 @@ defmodule IEx do
     IEx.Config[
       binding: opts[:binding] || [],
       scope: scope,
-      load_dot_iex: Keyword.get(opts, :load_dot_iex, true),
+      dot_iex_path: Keyword.get(opts, :dot_iex_path),
     ]
   end
 

lib/iex/lib/iex/cli.ex

@@ -19,7 +19,8 @@ defmodule IEx.CLI do
     else
       :user.start
       IO.puts "Warning: could not run smart terminal, falling back to dumb one"
-      IEx.start([], fn -> :elixir.start_cli end)
+      config = [dot_iex_path: find_dot_iex(:init.get_plain_arguments)]
+      IEx.start(config, fn -> :elixir.start_cli end)
     end
   end
 
@@ -37,12 +38,15 @@ defmodule IEx.CLI do
   end
 
   defp tty do
+    plain_args = :init.get_plain_arguments
+
+    config = [dot_iex_path: find_dot_iex(plain_args)]
     function = fn ->
-      IEx.start([], fn -> :elixir.start_cli end)
+      IEx.start(config, fn -> :elixir.start_cli end)
     end
 
     args =
-      if remote = get_remsh(:init.get_plain_arguments) do
+      if remote = get_remsh(plain_args) do
         unless is_alive do
           function = fn ->
             IO.puts(:stderr, "In order to use --remsh, you need to name the current node using --name or --sname. Aborting...")
@@ -60,6 +64,10 @@ defmodule IEx.CLI do
     :user_drv.start([:"tty_sl -c -e", args])
   end
 
+  defp find_dot_iex(['--dot-iex',h|_]), do: :unicode.characters_to_binary(h)
+  defp find_dot_iex([_|t]), do: find_dot_iex(t)
+  defp find_dot_iex([]), do: nil
+
   defp get_remsh(['--remsh',h|_]), do: list_to_atom(h)
   defp get_remsh([_|t]), do: get_remsh(t)
   defp get_remsh([]), do: nil

lib/iex/lib/iex/server.ex

@@ -10,12 +10,18 @@ defmodule IEx.Server do
 
   """
   def start(config) do
-    IO.puts "Interactive Elixir (#{System.version}) - press Ctrl+C to exit (type h() ENTER for help)"
     Process.put :iex_history, []
+
     { _, _, scope } = :elixir.eval('require IEx.Helpers', [], 0, config.scope)
     config = config.scope(scope)
-    if config.load_dot_iex, do:
-      config = load_dot_iex(config)
+
+    config = case config.dot_iex_path do
+      ""   -> config                     # don't load anything
+      nil  -> load_dot_iex(config)       # load .iex from predefined locations
+      path -> load_dot_iex(config, path) # load from `path`
+    end
+
+    IO.puts "Interactive Elixir (#{System.version}) - press Ctrl+C to exit (type h() ENTER for help)"
     do_loop(config)
   end
 
@@ -91,8 +97,12 @@ defmodule IEx.Server do
 
   # Locates and loads an .iex file from one of predefined locations. Returns
   # new config.
-  defp load_dot_iex(config) do
-    candidates = Enum.map [".iex", "~/.iex"], Path.expand(&1)
+  defp load_dot_iex(config, path // nil) do
+    candidates = if path do
+      [path]
+    else
+      Enum.map [".iex", "~/.iex"], Path.expand(&1)
+    end
     path = Enum.find candidates, fn path -> File.regular?(path) end
     if nil?(path) do
       config