Use importlib instead of janky use of eval.

Apparently needed for Python 3.13 in any case.

Fix #24.

python/gegede/builder.py

@@ -5,7 +5,7 @@
 
 from collections import OrderedDict
 
-from .util import list_match
+from .util import list_match, make_class
 
 class Builder(object):
     '''
@@ -88,10 +88,8 @@ def add_builder(self, name, klass):
             print ('Builder already registered: "%s"' % name)
             return
 
-        if (isinstance(klass, type(""))):
-            mod,name = klass.rsplit('.',1) # this seems dirty
-            exec ('import %s' % mod)
-            klass = eval(klass)
+        if isinstance(klass, str):
+            klass = make_class(klass)
         builder = klass(name)
         self.builders[name] = builder
         return

python/gegede/configuration.py

@@ -5,6 +5,7 @@
 import os
 import re
 from collections import OrderedDict
+from .util import make_class
 
 def parse(filenames):
     '''Parse configuration files.
@@ -40,6 +41,7 @@ def cfg2pod(cfg):
         pod[secname] = secdat
     return pod
 
+
 interp_reobj = re.compile(r'{([\w:]+)}')
 def interpolate_value(value, secname, sections):
     def getter(match):
@@ -53,6 +55,7 @@ def getter(match):
     ret = re.subn(interp_reobj, getter, value)
     return ret[0]
 
+
 def interpolate(sections):
     '''Perform string interpolation values <sections>.
 
@@ -74,15 +77,12 @@ def interpolate(sections):
         if changed:
             continue
         break
-
-
 
-def make_class(fqclass):
-    mod, cls = fqclass.rsplit('.',1)
-    exec('import %s' % mod) # better way?
-    return eval(fqclass)
 
 def make_value(v, **kwds):
+    '''
+    Return value of string.
+    '''
     from . import Quantity
     return eval(v, globals(), dict(Q=Quantity, **kwds))
 

python/gegede/export/__init__.py

@@ -6,17 +6,18 @@
 
 '''
 
+from gegede.util import make_module
+
 class Exporter(object):
     '''
     Wrapper around an exporter module which helps to enforce the conventions.
     '''
     def __init__(self, mod):
-        if isinstance(mod, type("")):
+        if isinstance(mod, str):
             if not '.' in mod:
                 mod = 'gegede.export.' + mod
             print ('Importing: "%s"' % mod)
-            exec('import %s' % mod)
-            mod = eval(mod)
+            mod = make_module(mod)
         self.mod = mod
 
         self.obj = None

python/gegede/util.py

@@ -2,6 +2,7 @@
 '''
 '''
 
+from importlib import import_module
 from gegede import Quantity
 
 def wash_units(obj, lunit='cm', aunit='radian'):
@@ -71,3 +72,19 @@ def list_match(values, entry = None, deref = lambda x: x):
         ret.append(v)
     return list(ret)
 
+
+def make_module(mod):
+    '''
+    Return a module object given pkg.mod string.
+    '''
+    return import_module(mod)
+
+
+def make_class(fqclass):
+    '''
+    Return a class given pkg.mod.Class string.
+    '''
+    mod, cls = fqclass.rsplit('.',1)
+    mod = import_module(mod)
+    return getattr(mod, cls)
+