Deprecate mix run EXPR in favor of mix run -e EXPR

Author: José Valim

CHANGELOG.md

@@ -28,6 +28,7 @@
   * [File] `File.iterator!/2` and `File.biniterator!/2` are deprecated in favor of `File.stream!/2` and `File.binstream!/2`
   * [Kernel] Deprecate recently added `quote binding: ...` in favor of the clearer `quote bind_quoted: ...`
   * [Kernel] Deprecate `Kernel.float/1` in favor of a explicit conversion
+  * [Mix] Deprecate `mix run EXPR` in favor of `mix run -e EXPR`
   * [Record] `Record.__index__/2` deprecated in favor of `Record.__record__(:index, key)`
 
 * backwards incompatible changes

lib/mix/lib/mix/tasks/run.ex

@@ -1,35 +1,37 @@
 defmodule Mix.Tasks.Run do
   use Mix.Task
 
-  @shortdoc "Run the given expression"
+  @shortdoc "Run the given file or expression"
 
   @moduledoc """
-  Run the given expression in the application context.
+  Runs the given file or expession in the context of the application.
 
   Before running the code, it invokes the app.start task
   which defaults to compile and load your project.
 
   ## Command line options
 
+  * `--eval`, `-e` - Evaluates the given code
   * `--require`, `-r` - Requires pattern before running the command
   * `--parallel-require`, `-pr` - Requires pattern in parallel
   * `--no-halt` - Does not halt the system after running the command
-  * `--no-compile` - Do not compile even if files require compilation;
-  * `--no-start` - Do not start applications after compilation;
+  * `--no-compile` - Does not compile even if files require compilation
+  * `--no-start` - Does not start applications after compilation
 
   ## Examples
 
-      mix run Hello.world
-      mix run "Some.function with_args"
+      mix run -e Hello.world
+      mix run -e "Some.function with_args"
+      mix run -r some_file.exs
 
   Command line options given to the `elixir` executable can be passed as:
 
-      elixir --sname hello -S mix run "My.code"
+      elixir --sname hello -S mix run -e "My.code"
 
   """
   def run(args) do
     { opts, head } = OptionParser.parse_head(args,
-      aliases: [r: :require, pr: :parallel_require],
+      aliases: [r: :require, pr: :parallel_require, e: :eval],
       switches: [parallel_require: :keep, require: :keep])
 
     Mix.Task.run "app.start", args
@@ -40,12 +42,17 @@ defmodule Mix.Tasks.Run do
           value |> filter_patterns |> Kernel.ParallelRequire.files
         :require ->
           value |> filter_patterns |> Enum.each Code.require_file(&1)
+        :eval ->
+          Code.eval_string(value)
         _ ->
           :ok
       end
     end
 
-    if head != [], do: Code.eval_string Enum.join(head, " ")
+    if head != [] do
+      Mix.shell.error "[WARNING] mix run EXPR is deprecated, please use mix run -e EXPR instead"
+      Code.eval_string Enum.join(head, " ")
+    end
     if opts[:no_halt], do: :timer.sleep(:infinity)
   end