From d7be7d038ab4ffb3af4e8f32334b313f6878049c Mon Sep 17 00:00:00 2001
From: Markus Reiter <me@reitermark.us>
Date: Wed, 19 Aug 2020 07:33:07 +0200
Subject: [PATCH] Document `SystemCommand`.

---
 Library/Homebrew/system_command.rb | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Library/Homebrew/system_command.rb b/Library/Homebrew/system_command.rb
index b507ec1434..05c4cb86c2 100644
--- a/Library/Homebrew/system_command.rb
+++ b/Library/Homebrew/system_command.rb
@@ -9,6 +9,9 @@ require "extend/io"
 require "extend/hash_validator"
 using HashValidator
 
+# Make `system_command` available everywhere.
+#
+# @api private
 module Kernel
   def system_command(*args)
     SystemCommand.run(*args)
@@ -19,6 +22,9 @@ module Kernel
   end
 end
 
+# Class for running sub-processes and capturing their output and exit status.
+#
+# @api private
 class SystemCommand
   include Context
   extend Predicable
@@ -167,6 +173,7 @@ class SystemCommand
     sources.each(&:close_read)
   end
 
+  # Result containing the output and exit status of a finished sub-process.
   class Result
     include Context