Added conda virtualenv support to python module. (#1505)

* Added conda virtualenv support to python module
* Added instructions for Python module options to README

Thanks to @egpbos for the original feature and @ickc for fixing the merge conflicts.

modules/python/README.md

@@ -3,6 +3,19 @@ Python
 
 Enables local Python and local Python package installation.
 
+Settings
+--------
+
+This module supports virtual environments from conda and virtualenvwrapper. By default, only virtualenvwrapper is enabled. To disable virtualenvwrapper, add the following to *zpreztorc*.
+
+    zstyle ':prezto:module:python' skip-virtualenvwrapper-init 'on'
+
+Conda support is enabled by adding the following to *zpreztorc*.
+
+    zstyle ':prezto:module:python' conda-init 'on'
+
+Caution: using conda and virtualenvwrapper at the same time may cause conflicts.
+
 Local Python Installation
 -------------------------
 

modules/python/functions/python-info

@@ -4,6 +4,7 @@
 #
 # Authors:
 #   Sorin Ionescu <sorin.ionescu@gmail.com>
+#   Patrick Bos <egpbos@gmail.com>
 #
 
 # function python-info {
@@ -22,4 +23,11 @@ if [[ -n "$VIRTUAL_ENV" ]]; then
   python_info[virtualenv]="$virtualenv_formatted"
 fi
 
+# Do the same for Conda virtual environments
+if [[ -n "$CONDA_DEFAULT_ENV" ]]; then
+  zstyle -s ':prezto:module:python:info:virtualenv' format 'virtualenv_format'
+  zformat -f virtualenv_formatted "$virtualenv_format" "v:${CONDA_DEFAULT_ENV:t}"
+  python_info[virtualenv]="$virtualenv_formatted"
+fi
+
 # }

modules/python/init.zsh

@@ -4,6 +4,7 @@
 # Authors:
 #   Sorin Ionescu <sorin.ionescu@gmail.com>
 #   Sebastian Wiesner <lunaryorn@googlemail.com>
+#   Patrick Bos <egpbos@gmail.com>
 #
 
 # Load manually installed pyenv into the shell session.
@@ -144,6 +145,19 @@ if (( $#commands[(i)pip(|[23])] )); then
   unset cache_file pip_command
 fi
 
+# Load conda into the shell session, if requested
+zstyle -T ':prezto:module:python' conda-init
+if (( $? && $+commands[conda] )); then
+  if (( $(conda ..changeps1) )); then
+    echo "To make sure Conda doesn't change your prompt (should do that in the prompt module) run:\n  conda config --set changeps1 false"
+    # TODO:
+    # We could just run this ourselves. In an exit hook
+    # (add zsh-hook zshexit [(anonymous) function]) we could then set it back
+    # to the way it was before we changed it. However, I'm not sure if this is
+    # exception safe, so left it like this for now.
+  fi
+fi
+
 #
 # Aliases
 #