New bjam.variable function exposed to Python.

[SVN r39876]

src/engine/builtins.c

@@ -1744,6 +1744,30 @@ bjam_define_action(PyObject* self, PyObject *args)
     return Py_None;    
 }
 
+/* Returns the value of a variable in root Jam module.  */
+PyObject*
+bjam_variable(PyObject* self, PyObject* args)
+{
+    char *name;
+    LIST* value;
+    PyObject *result;
+    int i;
+
+    if (!PyArg_ParseTuple(args, "s", &name))
+        return NULL;
+
+    enter_module(root_module());
+    value = var_get(name);
+    exit_module(root_module());
+
+    result = PyList_New(list_length(value));
+    for (i = 0; value; value = list_next(value), ++i)
+        PyList_SetItem(result, i, PyString_FromString(value->string));
+
+    return result;
+}
+
+
 #endif
 
 #ifdef HAVE_POPEN

src/engine/jam.c

@@ -209,6 +209,9 @@ static void run_unit_tests()
 
     extern PyObject*
     bjam_define_action(PyObject* self, PyObject* args);
+
+    extern PyObject*
+    bjam_variable(PyObject* self, PyObject* args);
 #endif
 
 int  main( int argc, char **argv, char **arg_environ )
@@ -344,6 +347,8 @@ int  main( int argc, char **argv, char **arg_environ )
                  "Imports Python callable to bjam."},
                 {"define_action", bjam_define_action, METH_VARARGS,
                  "Defines a command line action."},
+                {"variable", bjam_variable, METH_VARARGS,
+                 "Obtains a variable from bjam's global module."},
                 {NULL, NULL, 0, NULL}
             };