add completions to ${...}

CHANGELOG.rst

@@ -11,6 +11,8 @@ Current Developments
 * Added comma literals to subproc mode.
 * ``@$(cmd)`` has been added as a subprocess-mode operator, which replaces in
   the subprocess command itself with the result of running ``cmd``.
+* The ``${...}`` shortcut for ``__xonsh_env__`` now returns appropriate 
+  completion options
 
 **Changed:**
 

xonsh/completer.py

@@ -526,11 +526,11 @@ class Completer(object):
         expr = subexpr_from_unbalanced(expr, '{', '}')
         _ctx = None
         try:
-            val = eval(expr, ctx)
+            val = builtins.__xonsh_execer__.eval(expr, ctx)
             _ctx = ctx
         except:  # pylint:disable=bare-except
             try:
-                val = eval(expr, builtins.__dict__)
+                val = builtins.__xonsh_execer__.eval(expr, builtins.__dict__)
                 _ctx = builtins.__dict__
             except:  # pylint:disable=bare-except
                 return attrs  # anything could have gone wrong!
@@ -539,7 +539,7 @@ class Completer(object):
         opts = []
         for i in _opts:
             try:
-                eval('{0}.{1}'.format(expr, i), _ctx)
+                builtins.__xonsh_execer__.eval('{0}.{1}'.format(expr, i), _ctx)
             except:  # pylint:disable=bare-except
                 continue
             else: