add recursive version of PyCall's pywrap

Will be used to have deeply nested Julia Modules for deeply nested
Python modules Eg, os.path.genericpath.* in python becomes
os.path.genericpath.* in Julia.

This version only works with modules, not Python classes.

Thanks to James Porter at the Recurse Center for helping with this!

3 files changed, 65 insertions, 0 deletions

diff --git a/src/pyrecwrap.jl b/src/pyrecwrap.jl
new file mode 100644
index 0000000..7b31e56
--- /dev/null
+++ b/src/pyrecwrap.jl
@@ -0,0 +1,56 @@
+
+# This file contains a recursive version of the pywrap() function from PyCall:
+# it will generate nested Julia Modules for nested Python modules.
+# This extends to recursive or infinitely looping modules. For example, the
+# Python "os" module goes infinitely deep:
+#
+#   os.path.genericpath.os.path.genericpath.os.path.genericpath.os.path...
+#
+# It was created for PyX.jl because PyX has deeply nested modules (eg,
+# pyx.graph.graphxy), which are not handled by the generic pywrap() from
+# PyCall.
+
+_pyrecwrap_cache = Dict{PyObject,Module}()
+
+function pyrecwrap(o::PyObject, mname::Symbol=:__anon__)
+    members = convert(Vector{Tuple{AbstractString,PyObject}},
+                      pycall(PyCall.inspect["getmembers"], PyObject, o))
+    if PyCall.pyversion >= v"3"
+        # Blacklist the "inspect" module under Python3; fail if called on it, and filter it
+        # out of recursive imports.
+        # See also: https://github.com/stevengj/PyCall.jl/issues/252
+        if o == PyCall.inspect
+            error("Wrapping the 'inspect' module under Python3 causes a hang")
+        end
+        filter!(m -> !(m[1] == PyCall.inspect), members)
+    end
+    filter!(m -> !(m[1] in PyCall.reserved), members)
+    m = Module(mname, false)
+    # Preload module cache with this (so far empty) module
+    _pyrecwrap_cache[o] = m
+    consts = Expr[]
+    for (ms, mo) in members     # ms is Symbol, mo is PyObject)
+        if pyisinstance(mo, PyCall.@pyglobalobj :PyModule_Type)
+            if mo == PyCall.inspect
+                continue
+            end
+            # Before recursing, check if we've seen this python module before
+            if !haskey(_pyrecwrap_cache, mo)
+                _pyrecwrap_cache[mo] = pyrecwrap(mo)
+            end
+            mm = _pyrecwrap_cache[mo]
+            push!(consts, Expr(:const, Expr(:(=), symbol(ms), mm)))
+        else
+            push!(consts, Expr(:const, Expr(:(=), symbol(ms), convert(PyAny, mo))))
+        end
+    end
+    exports = try
+                  convert(Vector{Symbol}, o["__all__"])
+              catch
+                  [symbol(x[1]) for x in filter(x -> x[1][1] != '_', members)]
+              end
+    eval(m, Expr(:toplevel, consts..., :(pymember(s) = $(getindex)($(o), s)),
+                 Expr(:export, exports...)))
+    m
+end
+
diff --git a/test/runtests.jl b/test/runtests.jl
index d0bb3c7..c4beb52 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -3,8 +3,13 @@ println("Importing libs...")
 include("../src/PyX.jl")
 using PyX
 using LaTeXStrings
+using PyCall
 using Base.Test
 
+##### Helpers
+println("Testing helpers...")
+include("test_pyrecwrap.jl")
+
 ##### Setup Common Objects
 println("Creating test objects...")
 include("test_objects.jl")
diff --git a/test/test_pyrecwrap.jl b/test/test_pyrecwrap.jl
new file mode 100644
index 0000000..cef3f08
--- /dev/null
+++ b/test/test_pyrecwrap.jl
@@ -0,0 +1,4 @@
+
+os_test = PyX.pyrecwrap(pyimport("os"))
+@test os_test.path.genericpath.os.path.genericpath.os.path.genericpath != nothing
+