themes/sirup: Show VirtualEnv

Added the ability to show the current Virtual Env when using Python Virtual Env.
If there's not vitual env, the theme works normal.

themes/sirup/sirup.theme.sh

@@ -2,6 +2,16 @@
 # For unstaged(*) and staged(+) values next to branch name in __git_ps1
 GIT_PS1_SHOWDIRTYSTATE="enabled"
 
+function omb_theme_syrup_python_venv {
+  local python_venv=""
+
+  if [[ -n "${VIRTUAL_ENV}" ]]; then
+    python_venv=$(basename "${VIRTUAL_ENV}")
+  fi
+
+  [[ -n "${python_venv}" ]] && echo "[${python_venv}] "
+}
+
 function _omb_theme_sirup_rubygem {
   local gemset=$(command awk -F'@' '{print $2}' <<< "$GEM_HOME")
   [[ $gemset ]] && gemset="@$gemset"
@@ -15,7 +25,7 @@ function _omb_theme_sirup_rubygem {
 
 function _omb_theme_PROMPT_COMMAND {
   # Check http://github.com/Sirupsen/dotfiles for screenshot
-  PS1="$_omb_prompt_navy\W/$_omb_prompt_bold_navy$(_omb_theme_sirup_rubygem)$_omb_prompt_bold_green$(__git_ps1 " (%s)") ${_omb_prompt_normal}$ "
+  PS1="$_omb_prompt_purple$(omb_theme_syrup_python_venv)$_omb_prompt_navy\W/$_omb_prompt_bold_navy$(_omb_theme_sirup_rubygem)$_omb_prompt_bold_green$(__git_ps1 " (%s)") ${_omb_prompt_normal}$ "
 }
 
 _omb_util_add_prompt_command _omb_theme_PROMPT_COMMAND