[Adonthell-devel] Finding python wrappers from code

[Michał Kaliński]

Hi

Kai suggested, that it may be possible to set the path to python
modules from the program itself, like it's done for user data
directory. I've looked into that, but it's only partially possible, I
think. I've managed to get it working for tests that call the engine
from C++ (like worldtest), but not from Python scripts - those scripts
obviously already need to know where to find adonthell module before
they call a single function from it, so it already needs to be on
PYTHONPATH.

I'm not sure if it's worth to implement such partial solution, but
anyway, here's what I've done:

CMakeLists.txt:
----
@@ -177,6 +177,8 @@ include(config/PythonExtraLibs.cmake)
        message(STATUS
                "\tSITEPKG: ${PYTHON_SITE_PACKAGE_DIR}")

+add_definitions(-DPYTHONSPDIR="${ESCAPE}${PYTHON_SITE_PACKAGE_DIR}${ESCAPE}")
+
 #######################
 # libZ
 #######################
----

src/main/Makefile.am:
----
@@ -14,7 +14,7 @@ libadonthell_main_la_SOURCES = \
        adonthell.cc \
        main.cc

-libadonthell_main_la_CXXFLAGS = $(PY_CFLAGS) $(AM_CXXFLAGS)
+libadonthell_main_la_CXXFLAGS = $(PY_CFLAGS)
-DPYTHONSPDIR=\"$(pyexecdir)\" $(AM_CXXFLAGS)
 libadonthell_main_la_LIBADD = $(PY_LIBS) -lltdl \
     $(top_builddir)/src/base/libadonthell_base.la \
     $(top_builddir)/src/gfx/libadonthell_gfx.la \
----

src/main/adonthell.cc:
----
@@ -86,6 +86,11 @@ bool app::init_modules (const u_int16 & modules)
         {
             python::init ();
             PySys_SetArgv (Argc, Argv);
+
+            // add location of adonthell modules,
+            // to allow not setting PYTHONPATH
+            // if we're called from Python, it's already too late for that
+            python::add_search_path (PYTHONSPDIR);
         }
         // avoid shutting down Python in that case
         else
----

I mostly mimicked how PKGLIBDIR is set. I don't think this requires
anything more sophisticated then a macro, since the location should
not normally change after installation.

Michal