Use user_ns = __main__.__dict__ so that py"..." works

Author: tkf

README.md

@@ -16,7 +16,8 @@ can switch back to Julia REPl by `backspace` or `ctrl-h` key (like
 other REPL modes).  For older versions of IPython, exiting IPython as
 usual (e.g., `ctrl-d`) brings you back to the Julia REPL.  Re-entering
 IPython keeps the previous state.  Use pre-defined `Main` object to
-access Julia namespace from IPython.
+access Julia namespace from IPython.  Use `py"..."` string macro to
+access Python namespace from Julia.
 
 **Note:**
 First launch of IPython may be slow.

src/ipython_jl/entrypoints.py

@@ -24,8 +24,12 @@ def post_startup_configuration(ip):
 
 def ipython_options(**kwargs):
     from traitlets.config import Config
+    import __main__
 
-    user_ns = dict(
+    # Use `__main__.__dict__` so that IPython namespace can be
+    # retrieved from PyCall using `py"object"`.
+    user_ns = __main__.__dict__
+    user_ns.update(
         Main=get_main(**kwargs),
     )