fix problems with brew completion

- update plugin architecture
- completion function in $ZSH/functions/brew
- plugins/brew.plugin.zsh only activates

functions/brew/_brew

+#compdef brew
+#autoload
+
+# imported from the latest homebrew contributions
+
+_brew_all_formulae() {
+  formulae=(`brew search`)
+}
+
+_brew_installed_formulae() {
+  installed_formulae=(`brew list`)
+}
+
+local -a _1st_arguments
+_1st_arguments=(
+  'cat:display formula file for a formula'
+  'cleanup:uninstall unused and old versions of packages'
+  'create:create a new formula'
+  'deps:list dependencies and dependants of a formula'
+  'doctor:audits your installation for common issues'
+  'edit:edit a formula'
+  'home:visit the homepage of a formula or the brew project'
+  'info:information about a formula'
+  'install:install a formula'
+  'link:link a formula'
+  'list:list files in a formula or not-installed formulae'
+  'log:git commit log for a formula'
+  'outdated:list formulas for which a newer version is available'
+  'prune:remove dead links'
+  'remove:remove a formula'
+  'search:search for a formula (/regex/ or string)'
+  'unlink:unlink a formula'
+  'update:freshen up links'
+  'uses:show formulas which depend on a formula'
+)
+
+local expl
+local -a formula installed_formulae
+
+_arguments \
+  '(-v --verbose)'{-v,--verbose}'[verbose]' \
+  '(--version)--version[version information]' \
+  '(--prefix)--prefix[where brew lives on this system]' \
+  '(--cache)--cache[brew cache]' \
+  '*:: :->subcmds' && return 0
+
+if (( CURRENT == 1 )); then
+  _describe -t commands "brew subcommand" _1st_arguments
+  return
+fi
+
+case "$words[1]" in
+  list)
+    _arguments \
+      '(--unbrewed)--unbrewed[files in brew --prefix not controlled by brew]' \
+      '1: :->forms' &&  return 0
+
+      if [[ "$state" == forms ]]; then
+        _brew_installed_formulae
+        _requested installed_formulae expl 'installed formulae' compadd -a installed_formulae
+      fi ;;
+  install|home|log|info|uses|cat|deps)
+    _brew_all_formulae
+    _wanted formulae expl 'all formulae' compadd -a formulae ;;
+  remove|edit|xo)
+    _brew_installed_formulae
+    _wanted installed_formulae expl 'installed formulae' compadd -a installed_formulae ;;
+esac
+

plugins/brew.plugin.zsh

-#compdef brew
-
-# imported from the latest homebrew contributions
-
-_brew_all_formulae() {
-  formulae=(`brew search`)
-}
-
-_brew_installed_formulae() {
-  installed_formulae=(`brew list`)
-}
-
-local -a _1st_arguments
-_1st_arguments=(
-  'cat:display formula file for a formula'
-  'cleanup:uninstall unused and old versions of packages'
-  'create:create a new formula'
-  'deps:list dependencies and dependants of a formula'
-  'doctor:audits your installation for common issues'
-  'edit:edit a formula'
-  'home:visit the homepage of a formula or the brew project'
-  'info:information about a formula'
-  'install:install a formula'
-  'link:link a formula'
-  'list:list files in a formula or not-installed formulae'
-  'log:git commit log for a formula'
-  'outdated:list formulas for which a newer version is available'
-  'prune:remove dead links'
-  'remove:remove a formula'
-  'search:search for a formula (/regex/ or string)'
-  'unlink:unlink a formula'
-  'update:freshen up links'
-  'uses:show formulas which depend on a formula'
-)
-
-local expl
-local -a formula installed_formulae
-
-_arguments \
-  '(-v --verbose)'{-v,--verbose}'[verbose]' \
-  '(--version)--version[version information]' \
-  '(--prefix)--prefix[where brew lives on this system]' \
-  '(--cache)--cache[brew cache]' \
-  '*:: :->subcmds' && return 0
-
-if (( CURRENT == 1 )); then
-  _describe -t commands "brew subcommand" _1st_arguments
-  return
-fi
-
-case "$words[1]" in
-  list)
-    _arguments \
-      '(--unbrewed)--unbrewed[files in brew --prefix not controlled by brew]' \
-      '1: :->forms' &&  return 0
-
-      if [[ "$state" == forms ]]; then
-        _brew_installed_formulae
-        _requested installed_formulae expl 'installed formulae' compadd -a installed_formulae
-      fi ;;
-  install|home|log|info|uses|cat|deps)
-    _brew_all_formulae
-    _wanted formulae expl 'all formulae' compadd -a formulae ;;
-  remove|edit|xo)
-    _brew_installed_formulae
-    _wanted installed_formulae expl 'installed formulae' compadd -a installed_formulae ;;
-esac
+# add brew completion function to path
+fpath=($ZSH/functions/brew $fpath)
+autoload -U compinit
+compinit -i