fish completion: complete formula options

Library/Contributions/brew_fish_completion.fish

@@ -86,6 +86,20 @@ function __fish_complete_brew_no_command
   return 0
 end
 
+function __fish_brew_formula_arguments
+  set formulae (ls (brew --repository)/Library/Formula 2>/dev/null | sed 's/\.rb//g')
+  for formula in (ls (brew --repository)/Library/Aliases 2>/dev/null | sed 's/\.rb//g')
+    set formulae $formula $formulae
+  end
+
+  for cmd in (commandline -opc)
+    if contains -- $cmd $formulae
+      brew options $cmd --compact | tr ' ' '\n'
+    end
+  end
+end
+
+complete -c brew --arguments '(__fish_brew_formula_arguments)'
 complete -c brew -x -a "$commands" -n '__fish_complete_brew_no_command'
 complete -c brew -x -a '(__fish_complete_brew_argument)' -n '__fish_complete_brew_has_command'