virtualenv-python.el

(defun local-path (path)
  "Return the local portion of a path.

If PATH is local, return it unaltered.
If PATH is remote, return the remote diretory portion of the path."
  (if (tramp-tramp-file-p path)
      (elt (tramp-dissect-file-name path) 3)
    path))

(defun python-find-python-command (&optional root)
  "Return the python interpreter to use for ROOT."
  (let ((env-root (local-path
                   (locate-dominating-file
                    (or root default-directory) "bin/python"))))
    (or (when env-root (concat env-root "bin/python"))
        python-python-command)))

(defmacro with-virtualenv-python (&rest body)
  "Locate a local Python interpreter and make it available in the body."
  `(let* ((local-python-command (python-find-python-command))
          (python-command local-python-command)
          (python-python-command local-python-command)
          (test-case-python-executable local-python-command))
     ,@body))

(defun run-virtualenv-python ()
  (interactive)
  (with-virtualenv-python
   (run-python)))