Add Prezto version of agnoster theme

Own version making use of the 'editor' and 'git' Prezto modules.
Also incorporating updates introduced by the Oh My Zsh version
of this theme.

modules/prompt/functions/prompt_agnoster_setup

@@ -0,0 +1,100 @@
+# vim:ft=zsh ts=2 sw=2 sts=2
+# A Prezto version of Agnoster, a Powerline-inspired theme for Zsh.
+#
+# This theme requires a [patched Powerline
+# font](https://github.com/powerline/fonts). In addition, it looks better with
+# the [Solarized theme](https://github.com/altercation/solarized/).
+#
+# Based in the
+# [original theme](https://github.com/agnoster/agnoster-zsh-theme), in the
+# [Oh My Zsh version of
+# Agnoster](https://github.com/robbyrussell/oh-my-zsh/blob/master/themes/agnoster.zsh-theme),
+# and in the [Powerlevel9k theme](https://github.com/bhilburn/powerlevel9k).
+#
+# Uses the 'editor' and the 'git' Prezto modules.
+#
+# Author:
+#   Eric Nielsen <eric@amalgamar.com.br>
+#
+
+prompt_agnoster_precmd() {
+  RETVAL=$?
+  if [[ $+functions[git-info] ]]; then
+    git-info
+  fi
+}
+
+prompt_agnoster_separate_segment() {
+  print -n "%K{$1}"
+  if [[ -n "$2" ]]; then
+    print -n "%F{$2}${editor_info[keymap]}"
+  fi
+}
+
+prompt_agnoster_end_segment() {
+  print -n "%k%F{$1}${editor_info[keymap]}%f "
+}
+
+prompt_agnoster_build() {
+  # status and context segment
+  local segment=''
+  [[ $RETVAL -ne 0 ]] && segment+=' %F{red}✘'
+  [[ $UID -eq 0 ]] && segment+=' %F{yellow}⚡'
+  [[ $(jobs -l | wc -l) -gt 0 ]] && segment+=' %F{cyan}⚙'
+  if [[ "$USER" != "$DEFAULT_USER" || -n "$SSH_CLIENT" ]]; then
+    segment+=' %F{%(!.yellow.default)}$USER@%m%f'
+  fi
+  local bg=''
+  if [[ -n $segment ]]; then
+    prompt_agnoster_separate_segment black; bg=black
+    print -n "$segment "
+  fi
+  # dir segment
+  prompt_agnoster_separate_segment blue $bg; bg=blue
+  print -n ' %F{black}%~ '
+  # git segment
+  if [[ -n "$git_info" ]]; then
+    local new_bg="${git_info[color]}"
+    prompt_agnoster_separate_segment $new_bg $bg; bg=$new_bg
+    print -n ' %F{black}${(e)git_info[prompt]} '
+  fi
+  # end
+  prompt_agnoster_end_segment $bg
+}
+
+prompt_agnoster_setup() {
+  setopt LOCAL_OPTIONS
+  unsetopt XTRACE KSH_ARRAYS
+  prompt_opts=(cr percent subst)
+
+  # Load required functions.
+  autoload -Uz add-zsh-hook
+
+  # Add hook for calling git-info before each command.
+  add-zsh-hook precmd prompt_agnoster_precmd
+
+  zstyle ':prezto:module:editor:info:keymap:primary' format ''
+  zstyle ':prezto:module:editor:info:keymap:alternate' format '%S%s'
+
+  # Set git-info parameters.
+  zstyle ':prezto:module:git:info:branch' format ' %b'
+  zstyle ':prezto:module:git:info:commit' format '➦ %.7c'
+  zstyle ':prezto:module:git:info:ahead' format ' ↑%A'
+  zstyle ':prezto:module:git:info:behind' format ' ↓%B'
+  zstyle ':prezto:module:git:info:stashed' format ' ⍟%S'
+  zstyle ':prezto:module:git:info:indexed' format ' ✚'
+  zstyle ':prezto:module:git:info:unindexed' format ' ●'
+  zstyle ':prezto:module:git:info:untracked' format ' ?'
+  zstyle ':prezto:module:git:info:action' format ' | %s'
+  zstyle ':prezto:module:git:info:clean' format 'green'
+  zstyle ':prezto:module:git:info:dirty' format 'yellow'
+  zstyle ':prezto:module:git:info:keys' format \
+    'prompt' '$(coalesce "%b" "%c")%A%B%S%i%I%s' \
+    'color' '%C%D'
+
+  PROMPT='${(e)$(prompt_agnoster_build)}'
+  RPROMPT=''
+}
+
+prompt_agnoster_setup "$@"
+