Register content by module name, to avoid circular imports.

dungeonsheets/__init__.py

@@ -14,4 +14,3 @@ from dungeonsheets import background, features, race, spells, weapons, mechanics
 from dungeonsheets.character import Character
 from dungeonsheets.content_registry import import_homebrew
 from dungeonsheets.content import __version__
-

dungeonsheets/armor.py

@@ -1,3 +1,9 @@
+from dungeonsheets.content_registry import default_content_registry
+
+
+default_content_registry.add_module(__name__)
+
+
 class Shield:
     """A shield that can be worn on one hand."""
 

dungeonsheets/background.py

@@ -1,4 +1,8 @@
 from dungeonsheets import features as feats
+from dungeonsheets.content_registry import default_content_registry
+
+
+default_content_registry.add_module(__name__)
 
 
 class Background:

dungeonsheets/content_registry.py

@@ -1,20 +1,51 @@
+"""Registries for looking up pre-defined game content.
+
+The function *find_content* will find the class for a piece of content
+when given the name of that content. For example:
+``find_content("leather armor")`` will return the
+*dungeonsheets.armor.LeatherArmor* class.
+
+The *find_content* function is a shortcut that makes use of the
+*default_content_registry*, which is a *ContentRegistry* instance that
+is aware of all the content included in *dungeonsheets*. **New modules
+should register themselves** with the *default_content_registry*, best
+achieved by::
+
+    from content_registry import default_content_registry
+    default_content_registry.add_module(__name__)
+
+In the case of **homebrew content**, the python file may not be in the
+python path and so cannot be imported directly. In this case, the
+*import_homebrew* function will import the python file-name given and
+then register it with the *default_content_registry*, most often
+within a character sheet file. For example, if the *PaperSword* weapon
+class is defined in a separate file "my_homebrew.py", then in the
+character file::
+
+    from content_registry import import_homebrew
+    import_homebrew("my_homebrew.py")
+    
+    weapons = ["paper sword"]
+
+If homebrew content shares a name with canonical content, then lookup
+by string will raise an exception. In those situations, the homebrew
+content can be used directly from *import_homebrew*::
+
+    from content_registry import import_homebrew
+    campaign = import_homebrew("my_homebrew.py")
+    
+    weapons = [campaign.PaperSword]
+
+"""
+
+
+import sys
 from pathlib import Path
 from functools import lru_cache
 import importlib.util
 from typing import Union, List, Optional
 
-from dungeonsheets import (
-    weapons,
-    monsters,
-    race,
-    background,
-    armor,
-    spells,
-    infusions,
-    magic_items,
-    features,
-    exceptions,
-)
+from dungeonsheets import exceptions
 
 
 class ContentRegistry:
@@ -24,6 +55,28 @@ class ContentRegistry:
         self.modules = []
 
     def add_module(self, new_module):
+        """Register a module with this registry.
+
+        Adding the same module multiple times has no effect.
+
+        *new_module* can also be a string, in which case, an attempt
+        will be made to load the module from *sys.modules*. This way,
+        a module can register itself::
+
+            # Define classes, etc
+            ...
+            # Register the module
+            registry = ContentRegistry()
+            registry.add_module(__name__)
+        
+        """
+        # Try and look up the module by name
+        try:
+            new_module = sys.modules[new_module]
+        except KeyError:
+            if isinstance(new_module, str):
+                raise exceptions.ContentNotFound(f"Module could not be resolved: {repr(new_module)}")
+        # Add the imported module to the list for later
         if new_module not in self.modules:
             self.modules.append(new_module)
 
@@ -94,15 +147,6 @@ class ContentRegistry:
 
 
 default_content_registry = ContentRegistry()
-default_content_registry.add_module(weapons)
-default_content_registry.add_module(monsters)
-default_content_registry.add_module(race)
-default_content_registry.add_module(background)
-default_content_registry.add_module(armor)
-default_content_registry.add_module(spells)
-default_content_registry.add_module(infusions)
-default_content_registry.add_module(magic_items)
-default_content_registry.add_module(features)
 
 
 def find_content(name: str, valid_classes: Optional[List] = None):

dungeonsheets/features/__init__.py

@@ -16,3 +16,8 @@ from dungeonsheets.features.rogue import *
 from dungeonsheets.features.sorceror import *
 from dungeonsheets.features.warlock import *
 from dungeonsheets.features.wizard import *
+
+from dungeonsheets.content_registry import default_content_registry
+
+
+default_content_registry.add_module(__name__)

dungeonsheets/infusions.py

@@ -1,3 +1,9 @@
+from dungeonsheets.content_registry import default_content_registry
+
+
+default_content_registry.add_module(__name__)
+
+
 class Infusion:
     name = "Unknown infusion"
     item = "Item to be infused"

dungeonsheets/magic_items.py

@@ -1,3 +1,9 @@
+from dungeonsheets.content_registry import default_content_registry
+
+
+default_content_registry.add_module(__name__)
+
+
 class MagicItem:
     """
     Generic Magic Item. Add description here.

dungeonsheets/mechanics.py

@@ -1,6 +1,7 @@
 """Convenience module holding base classes for the various kinds of
 game mechanics."""
 
+from dungeonsheets.content import Content
 from dungeonsheets.spells import Spell
 from dungeonsheets.features import Feature
 from dungeonsheets.infusions import Infusion

dungeonsheets/monsters/__init__.py

@@ -1,3 +1,5 @@
+from dungeonsheets.content_registry import default_content_registry
+
 from dungeonsheets.monsters.monsters import *
 from dungeonsheets.monsters.monsters_a import *
 from dungeonsheets.monsters.monsters_b import *
@@ -25,3 +27,6 @@ from dungeonsheets.monsters.monsters_w import *
 from dungeonsheets.monsters.monsters_x import *
 from dungeonsheets.monsters.monsters_y import *
 from dungeonsheets.monsters.monsters_z import *
+
+
+default_content_registry.add_module(__name__)

dungeonsheets/race.py

@@ -2,6 +2,10 @@ from collections import defaultdict
 
 from dungeonsheets import features as feats
 from dungeonsheets import spells, weapons
+from dungeonsheets.content_registry import default_content_registry
+
+
+default_content_registry.add_module(__name__)
 
 
 class Race:

dungeonsheets/spells/__init__.py

@@ -26,3 +26,8 @@ from dungeonsheets.spells.spells_w import *
 from dungeonsheets.spells.spells_x import *
 from dungeonsheets.spells.spells_y import *
 from dungeonsheets.spells.spells_z import *
+
+from dungeonsheets.content_registry import default_content_registry
+
+
+default_content_registry.add_module(__name__)

dungeonsheets/weapons.py

@@ -1,3 +1,9 @@
+from dungeonsheets.content_registry import default_content_registry
+
+
+default_content_registry.add_module(__name__)
+
+
 class Weapon:
     name = ""
     cost = "0 gp"

examples/gm-session-notes.py

@@ -5,6 +5,9 @@ monsters, etc.
 
 """
 
+from dungeonsheets import mechanics
+
+
 # This line (or one like it) is required in order for dungeonsheets to
 # recognize the file.
 dungeonsheets_version = "0.15.0"
@@ -36,14 +39,15 @@ monsters = ["aboleth", "wolf", "giant eagle", "Vashta Nerada", "priest"]
 # make up the body
 
 
-class BBEGMotivation():
+class BBEGMotivation(mechanics.Content):
     """Hans Gruber is after the $640 in bearer bonds stored in *Nakatomi
     plaza*.
 
     """
     name = "Big-Bad-Evil-Guy Motivation"
 
-class BarFight():
+
+class BarFight(mechanics.Content):
     """If the characters decide to go to the *Alliance Friendly Bar*,
     they will probably have to fight their way out against 5 enemies
     (3 Veteran, 2 Soldier).

tests/test_content_registry.py

@@ -14,6 +14,17 @@ class TestContentRegistry(TestCase):
         creg.add_module(monsters)
         self.assertEqual(len(creg.modules), 1)
 
+    def test_add_module_by_name(self):
+        # Check that a module gets converted to a module instance
+        creg = ContentRegistry()
+        creg.add_module("dungeonsheets.monsters")
+        self.assertEqual(len(creg.modules), 1)
+        self.assertFalse(isinstance(creg.modules[0], str),
+                         "String not converted to module.")
+        # Check if is indempotent
+        creg.add_module("dungeonsheets.monsters")
+        self.assertEqual(len(creg.modules), 1)
+
     def test_findattr(self):
         """Check if the function can find attributes."""