lib/pycall/import.rb in pycall-0.1.0.alpha.20170502 vs lib/pycall/import.rb in pycall-0.1.0.alpha.20170711

@@ -25,30 +25,63 @@
       raise PyError.fetch unless mod
 
       define_singleton_method(as) { mod }
     end
 
+    # This function is implemented as a mimic of `import_from` function defined in `Python/ceval.c`.
     def pyfrom(mod_name, import: nil)
       raise ArgumentError, "missing identifiers to be imported" unless import
 
-      mod = PyCall.import_module(mod_name)
-      raise PyError.fetch unless mod
+      mod_name = mod_name.to_str if mod_name.respond_to? :to_str
+      mod_name = mod_name.to_s if mod_name.is_a? Symbol
 
-      case import
-      when Hash
-        import.each do |attr, as|
-          val = PyCall.getattr(mod, attr)
-          define_name(as, val)
+      import = Array(import)
+      fromlist = LibPython.PyTuple_New(import.length)
+      import.each_with_index do |import_name, i|
+        name = case import_name
+               when assoc_array_matcher
+                 import_name[0]
+               when Symbol, String
+                 import_name
+               end
+        LibPython.PyTuple_SetItem(fromlist, i, Conversions.from_ruby(name))
+      end
+
+      main_dict = PyCall::Eval.__send__ :main_dict
+      globals = main_dict.__pyobj__ # FIXME: this should mimic to `import_name` function defined in `Python/ceval.c`.
+      locals = main_dict.__pyobj__ # FIXME: this should mimic to `import_name` function defined in `Python/ceval.c`.
+      level = 0 # TODO: support prefixed dots (#25)
+      mod = LibPython.PyImport_ImportModuleLevel(mod_name, globals, locals, fromlist, level)
+      raise PyError.fetch if mod.null?
+      mod = mod.to_ruby
+
+      import.each do |import_name|
+        case import_name
+        when assoc_array_matcher
+          name, asname = *import_name
+        when Symbol, String
+          name, asname = import_name, import_name
         end
-      when Array
-        import.each do |attr|
-          val = PyCall.getattr(mod, attr)
-          define_name(attr, val)
+
+        if PyCall.hasattr?(mod, name)
+          pyobj = PyCall.getattr(mod, name)
+          define_name(asname, pyobj)
+          next
         end
-      when Symbol, String
-        val = PyCall.getattr(mod, import)
-        define_name(import, val)
+
+        if PyCall.hasattr?(mod, :__name__)
+          pkgname = PyCall.getattr(mod, :__name__)
+          fullname = "#{pkgname}.#{name}"
+          module_dict = LibPython.PyImport_GetModuleDict()
+          if PyCall.getattr(module_dict, fullname)
+            pyobj = PyCall.getattr(module_dict, fullname)
+            define_name(asname, pyobj)
+            next
+          end
+        end
+
+        raise ArgumentError, "cannot import name #{fullname}" unless pyobj
       end
     end
 
     private
 
@@ -68,9 +101,15 @@
 
     def check_valid_module_variable_name(mod_name, var_name)
       var_name = var_name.to_s if var_name.kind_of? Symbol
       if var_name.include?('.')
         raise ArgumentError, "#{var_name} is not a valid module variable name, use pyimport #{mod_name}, as: <name>"
+      end
+    end
+
+    def assoc_array_matcher
+      @assoc_array_matcher ||= ->(ary) do
+        ary.is_a?(Array) && ary.length == 2
       end
     end
   end
 end