"module is in multiple packages" error

[Jona Joachim]

On Wed, 03 Jan 2007 21:45:17 -0600, Chris Nicholson-Sauls wrote:

> Jona Joachim wrote:
>> On Thu, 04 Jan 2007 01:17:33 +0100, Johan Granberg wrote:
>> 
>>> Jona Joachim wrote:
>>>
>>>> Hi!
>>>> I have to bother you with a beginner problem...
>>>> I want to develop a spring model engine where you have pointmasses
>>>> attached to spring which oscillate and stuff.
>>>> I created a module called "connectors" which contains all sorts of
>>>> connectors like springs, dampers, ... and a module called "point" which
>>>> contains pointmasses and hooks.
>>>> Now a connector should know what pointmasses are attached to it and a
>>>> pointmass should know to which connectors it is attached...
>>>> That's why point.d does a "private import connector" and connector.d does
>>>> a "private import point". This works very well in C with header files and
>>>> #ifdefs. However gdc throws following error:
>>>>
>>>> gdc -I/home/jona/prog/d/derelict -O2 -fno-strict-aliasing -c point.d
>>>> connector.d:5: module constructor.point is in multiple packages
>>>> constructor.point gmake: *** [point.o] Error 1
>>>>
>>>> Could anybody tell me how I should manage this kind of situation?
>>>>
>>>> Thanks a lot,
>>>> Jona
>>> Try declaring the modules explicityl.
>>>
>>> in point.d you write:
>>> module point;//or directoryname.subdirectoryname.point
>>>
>>> and in constructor you write:
>>> module constructor;
>>>
>>> if this doesent work how does you directory structur looks like (is point
>>> and constructor in the same directory?)
>> 
>> "constructor" is the (temporary) name of the project. All files are in the
>> same directory. I declared all modules explicitly like this:
>> module constructor.point;
>> or
>> module constructor.connector;
>> and so on.
>> 
>> I just found out that my problem disappears when I omit the
>> "constructor." part.
>> I don't understand why it all went fine using the above naming scheme
>> until two modules tried to import themselves mutually and then in that
>> case it didn't work anymore.
>> However I'm happy that it seems to work now!
>> 
>> Thanks for your help!
>> 
>> Jona
> 
> Aha!  There's your problem, then.  :)  You were declaring your modules as 
> "constructor.point" and then attempting to import them as "point".  Therefore the compiler 
> was seeing a package mismatch between package "constructor" and package-blank (or the 
> no-package, or whatever you want to call it).  Imports use the fully qualified name of the 
> module, but this name is technically determined by the initial "module X;" statement of 
> the target module.  Modules within the same package /still/ use the fully qualified name 
> to specify imports.
> 
> For example, a selection of the file structure of my own Bovis project:
> # bovis/
> #   Main
> #   Types
> #   db/
> #     Database
> #     Object
> 
> In order for bovis.Main to import the Database module, I issue:
> import bovis .db .Database ;
> 
> In order for bovis.db.Database to import the Object module, I issue:
> import bovis .db .Object ;
> 
> In order for bovis.db.Object to import the Types module, I issue:
> import bovis .Types ;
> 
> All the same.  Hopefully you understand what I'm trying to get across.  :)

I thought I had understood how it works but now I'm not so sure anymore...

Here is my folder:

constructor/
	Makefile
	connector.d
	figure.d
	global.d
	main.d
	point.d
	vector.d

Here are the first line of all file (module declaration and imports):

--connector.d--
module constructor.connector;

private import
  constructor.vector,
  constructor.point;

--figure.d--
module constructor.figure;

private import
  constructor.global,
  constructor.vector,
  constructor.point,
  constructor.connector;

--global.d--
module constructor.global;

--main.d--
module constructor.main;

private import
  constructor.global,
  constructor.vector,
  constructor.point,
  constructor.connector;

--point.d--
module constructor.point;

private import
  constructor.global,
  constructor.connector,
  constructor.vector;

--vector.d--
module constructor.vector;

private import
  constructor.global,
  std.math;



If I try to build this:

/home/jona/prog/d/constructor> gmake
/bin/rm -f global.o vector.o point.o connector.o figure.o main.o
gdc -I/home/jona/prog/d/derelict -O2 -fno-strict-aliasing -c global.d
gdc -I/home/jona/prog/d/derelict -O2 -fno-strict-aliasing -c vector.d
vector.d:4: module global cannot read file 'constructor/global.d'
gmake: *** [vector.o] Error 1


It seems like it tries to cd to constructor although it is already in the
constructor folder. According to what you said it should know this because
the name of the modules itself contains "constructor.".
If I just leave out all occurrences of "constructor." it compiles fine.

Jona