Adding Pyenv support to Python virtualenv as "fallback"

README.md

@@ -12,7 +12,7 @@ theme based on the
 simplicity, showing information only when it's relevant.
 
 It currently shows:
-- Current Python virtualenv
+- Current Python virtualenv; when using Pyenv and no active virtualenv shows the current Python version the shell uses
 - Current Ruby version using Rbenv; version and gemset when on RVM
 - Current Node.js version, through NVM
 - Git status
@@ -136,7 +136,7 @@ or don't want to see. All options must be overridden in your **.zshrc** file.
 |`BULLETTRAIN_CONTEXT_DEFAULT_USER`|none|Default user. If you are running with other user other than default, the segment will be showed.
 |`BULLETTRAIN_IS_SSH_CLIENT`|none|If `true`, the segment will be showed.
 
-### Python virtualenv
+### Python virtualenv (+Pyenv)
 
 |Variable|Default|Meaning
 |--------|-------|-------|

bullet-train.zsh-theme

@@ -361,6 +361,8 @@ prompt_virtualenv() {
   local virtualenv_path="$VIRTUAL_ENV"
   if [[ -n $virtualenv_path && -n $VIRTUAL_ENV_DISABLE_PROMPT ]]; then
     prompt_segment $BULLETTRAIN_VIRTUALENV_BG $BULLETTRAIN_VIRTUALENV_FG $BULLETTRAIN_VIRTUALENV_PREFIX" $(basename $virtualenv_path)"
+  elif which pyenv &> /dev/null; then
+    prompt_segment $BULLETTRAIN_VIRTUALENV_BG $BULLETTRAIN_VIRTUALENV_FG $BULLETTRAIN_VIRTUALENV_PREFIX" $(pyenv version | sed -e 's/ (set.*$//')"
   fi
 }