Add "loadblock_hooks = grow_saplings" to bravo.ini

automaton.diff

diff --git a/bravo/ibravo.py b/bravo/ibravo.py
index 4364969..6881d45 100644
--- a/bravo/ibravo.py
+++ b/bravo/ibravo.py
@@ -400,8 +400,16 @@ class IAutomaton(IBravoPlugin):
     processing on those blocks.
     """
 
-    blocks = Attribute("""
-        List of blocks which this automaton is interested in.
+    def loadblock_hook(chunk, blocks_found):
+        """
+        Do things.
+        
+        :param `Chunk` chunk: chunk containing blocks
+        :param list blocks: list of co-ordinate tuples of matched blocks (x, y, z)
+        """
+
+    blocks_want = Attribute("""
+        List of block types which this automaton is interested in.
         """)
 
 class IWorldResource(IBravoPlugin, IResource):
diff --git a/bravo/plugins/build_hooks.py b/bravo/plugins/build_hooks.py
index 98e2bff..bdad151 100644
--- a/bravo/plugins/build_hooks.py
+++ b/bravo/plugins/build_hooks.py
@@ -5,6 +5,7 @@ from bravo.blocks import blocks, items
 from bravo.entity import Chest, Sign
 from bravo.ibravo import IBuildHook
 from bravo.utilities import split_coords
+from bravo.terrain.trees import NormalTree
 
 class Tile(object):
     """
@@ -166,7 +167,33 @@ class BuildSnow(object):
 
     before = tuple()
     after = ("build",)
+    
+class GrowSapling(object):
+    """
+    Grows saplings when placed.
+
+    You almost certainly want to enable this plugin.
+    """
+    
+    implements(IBuildHook)
+
+    @inlineCallbacks
+    def build_hook(self, factory, player, builddata):
+        block = yield factory.world.get_block((builddata.x, builddata.y, builddata.z))
+        
+        if block == blocks["sapling"].slot:
+            tree = NormalTree(pos=(builddata.x, builddata.y, builddata.z))
+            tree.make_trunk(factory.world)
+            tree.make_foliage(factory.world)
+
+        returnValue((True, builddata))
+
+    name = "grow_sapling"
+
+    before = ("build","build_snow")
+    after = tuple()
 
 tile = Tile()
 build = Build()
 build_snow = BuildSnow()
+grow_sapling = GrowSapling()
diff --git a/bravo/plugins/physics.py b/bravo/plugins/physics.py
index ade3f33..25af131 100644
--- a/bravo/plugins/physics.py
+++ b/bravo/plugins/physics.py
@@ -6,7 +6,7 @@ from twisted.internet.task import LoopingCall
 from zope.interface import implements
 
 from bravo.blocks import blocks
-from bravo.ibravo import IBuildHook, IDigHook
+from bravo.ibravo import IBuildHook, IDigHook, IAutomaton
 from bravo.spatial import Block2DSpatialDict, Block3DSpatialDict
 
 FALLING = 0x8
@@ -448,7 +448,24 @@ class Redstone(object):
 
     before = ("build",)
     after = tuple()
+    
+class GrowSaplings(object):
+    
+    implements(IAutomaton)
+    
+    blocks_want = [blocks["sapling"].slot]
+    
+    def loadblock_hook(chunk, blocks_found):
+        for i in blocks_found:
+            print "Go go gadget sapling! %s" % i
+        pass
+        
+    name = "grow_saplings"
+
+    before = tuple()
+    after = tuple()
 
 water = Water()
 lava = Lava()
 redstone = Redstone()
+grow_saplings = GrowSaplings()
diff --git a/bravo/world.py b/bravo/world.py
index efe892f..288ff39 100644
--- a/bravo/world.py
+++ b/bravo/world.py
@@ -15,8 +15,8 @@ from bravo.chunk import Chunk
 from bravo.config import configuration
 from bravo.entity import Player
 from bravo.errors import SerializerReadException
-from bravo.ibravo import ISerializer, ISerializerFactory
-from bravo.plugin import (retrieve_named_plugins, verify_plugin,
+from bravo.ibravo import ISerializer, ISerializerFactory, IAutomaton
+from bravo.plugin import (retrieve_sorted_plugins, retrieve_named_plugins, verify_plugin,
     PluginException)
 from bravo.utilities import fork_deferred, split_coords
 
@@ -96,6 +96,9 @@ class World(object):
         except PluginException, pe:
             log.msg(pe)
             raise RuntimeError("Fatal error: Couldn't set up serializer!")
+            
+        names = configuration.getlistdefault(self.config_name, "loadblock_hooks", [])
+        self.loadblock_hooks = retrieve_sorted_plugins(IAutomaton, names)
 
         self.chunk_cache = weakref.WeakValueDictionary()
         self.dirty_chunk_cache = dict()
@@ -243,6 +246,18 @@ class World(object):
         # Apply the current season to the chunk.
         if self.season:
             self.season.transform(chunk)
+            
+        # Run IAutomatons/Load Block hooks for chunk
+        for automaton in self.loadblock_hooks:
+            blocks = [] # List of blocks matching types IAutomaton wanted
+            for search in automaton.blocks:
+                if (chunk.blocks == search).any():
+                    for ix, x in enumerate(chunk.blocks):
+                        for iy, y in enumerate(x):
+                            for iz, z in enumerate(y):
+                                if z == search:
+                                    blocks.append((ix,iy,iz))
+            automaton.loadblock_hook(chunk, blocks)
 
         # Since this chunk hasn't been given to any player yet, there's no
         # conceivable way that any meaningful damage has been accumulated;