Add the new utils plugin, change entity spawning and the lookup command plugins to use it.

data/plugins/cmd/lookup/lookup.rb

@@ -23,7 +23,7 @@ on :command, :lookup, RIGHTS_ADMIN do |player, command|
     next
   end
   
-  ids = locate_entity(type, name, limit).join(', ')
+  ids = find_entities(type, name, limit).join(', ')
   
   message = ids.empty? ? "Could not find an #{type} called #{name}." : "Possible ids are: #{ids}." 
   player.send_message(message)

data/plugins/entity/spawning/npc-spawn.rb

@@ -41,17 +41,7 @@ end
 
 # Returns an npc with the id and position specified by the hash.
 def get_npc(hash)
-  id = hash.delete(:id)
+  id = hash.delete(:id) || lookup_npc(hash.delete(:name))
-
-  if id == nil
-    name = hash.delete(:name).to_s.gsub('_', ' ')
-    if name.include?(' ')
-      id = name[name.rindex(' ') + 1, name.length - 1].to_i
-    end
-    id = locate_entity('npc', name, 1).first if id == nil || id == 0
-  end
-
-  raise "The npc called #{name} could not be identified." if id == nil
 
   z = hash.delete(:z)
   position = Position.new(hash.delete(:x), hash.delete(:y), z == nil ? 0 : z)
@@ -111,21 +101,6 @@ def direction_to_position(direction, position)
   end
 end
 
-
-# Locates an entity with the specified type (e.g. npc) and name, returning possible ids as an array.
-def locate_entity(type, name, limit=5)
-  ids = []
-  name.downcase!
-
-  Kernel.const_get("#{type.capitalize}Definition").definitions.each do |definition|
-    break if ids.length == limit
-    ids << definition.id.to_i if definition.name.to_s.downcase == name
-  end
-
-  return ids
-end
-
-
 # An action that spawns an npc temporarily, before executing an action.
 class TemporaryNpcAction < Action
   attr_reader :executions, :combative

data/plugins/entity/spawning/plugin.xml

@@ -10,5 +10,7 @@
   <scripts>
     <script>npc-spawn.rb</script>
   </scripts>
-  <dependencies />
+  <dependencies>
+    <dependency>util</dependency>
+  </dependencies>
 </plugin>

data/plugins/util/command.rb

@@ -0,0 +1,11 @@
+
+# Checks whether the amount of arguments provided is correct, sending the player the specified message if not.
+def valid_arg_length(args, length, player, message)
+  valid = length.kind_of?(Range) ? length.include?(args.length) : length == args.length
+
+  if (!valid)
+    player.send_message(message)
+    return false
+  end
+  return true
+end

data/plugins/util/intercept.rb

@@ -0,0 +1,27 @@
+# Essentially a wrapper for specific message types to make them easier to use. Only supports the interception of a message type once (for good reason - this is supposed to
+# be a utility, not a chain of interceptors inside the existing chain).
+#
+# Plugins that wish to expand the list of available message types (you probably don't) should use the add_interception method - see the item-on-item script for example usage.
+# 
+# If you only wish to intercept a message, use the intercept method, e.g.
+#
+# intercept :item_on_item, used_id, target_id, :irreversible do |ctx, player, message|
+#   # code here
+# end
+
+
+# Calls the registered interception(s), if applicable.
+def intercept(message, *args, &block)
+  raise 'Error - interceptions must provide a block.' unless block_given?
+  interception = INTERCEPTIONS[message]
+
+  if interception == nil then raise "No interception for message #{message}" else interception.call(*args, block) end
+end
+
+# Adds an interception.
+def add_interception(message, &block)
+  INTERCEPTIONS[message] = block
+end
+
+private
+INTERCEPTIONS = {}

data/plugins/util/item-on-item-intercept.rb

@@ -0,0 +1,46 @@
+
+# Adds an interception for the ItemOnItem message
+add_interception :item_on_item do |used, target, reversible, block|
+  interception = ItemOnItemPair.new(used, target)
+
+  ITEM_PAIRS[interception] = block
+  ITEM_PAIRS[interception.reverse] = block if reversible == :reversible
+end
+
+private
+
+# A hash of ItemOnItemPairs to blocks.
+ITEM_PAIRS = {}
+
+# A pair of items that will cause a block to be executed if one (the 'used' item) is used on the other (the 'target' item).
+class ItemOnItemPair
+  attr_reader :used, :target
+
+  def initialize(used, target)
+    @used = used
+    @target = target
+  end
+
+  # Returns a new ItemOnItemPair that is the reverse of this.
+  def reverse
+    return ItemOnItemPair.new(@target, @used)
+  end
+
+  def eql?(other)
+    return (other.kind_of?(ItemOnItemPair) && @used == other.used && @target == other.target)
+  end
+
+  def hash
+    return @used << 16 | @target
+  end
+
+end
+
+# Adds a message handler to the item on item message.
+on :message, :item_on_item do |ctx, player, message|
+  used, target = message.id, message.target_id
+  pair = ItemOnItemPair.new(used, target)
+  block = ITEM_PAIRS[pair]
+
+  block.call(ctx, player, message) unless block == nil
+end

data/plugins/util/name-lookup.rb

@@ -0,0 +1,51 @@
+require 'java'
+
+# Looks up the id of the npc with the specified name.
+def lookup_npc(name)
+  return lookup_entity('npc', name)
+end
+
+# Looks up the id of the item with the specified name.
+def lookup_item(name)
+  return lookup_entity('item', name)
+end
+
+# Looks up the id of the object with the specified name.
+def lookup_object(name)
+  return lookup_entity('object', name)
+end
+
+# Looks up the id of an entity of the specified type (either 'npc', 'item', or 'object')
+def lookup_entity(type, symbol)
+  symbol = symbol.to_s
+  cached = NAME_CACHE[type + symbol]
+  return cached unless cached == nil
+
+  name = symbol.to_s.gsub('_', ' ')
+  if name.include?(' ')
+    id = name[name.rindex(' ') + 1, name.length - 1].to_i
+  end
+  id = find_entities(type, name, 1).first if id == nil || id == 0
+  
+  if id == nil
+    raise "The #{type} called #{name} could not be identified."
+  end
+
+  NAME_CACHE[type + symbol] = id
+  return id
+end
+
+# Finds entities with the specified type (e.g. npc) and name, returning possible ids as an array.
+def find_entities(type, name, limit=5)
+  ids = []; name.downcase!
+
+  Kernel.const_get("#{type.capitalize}Definition").definitions.each do |definition|
+    break if ids.length == limit
+    ids << definition.id.to_i if definition.name.to_s.downcase == name
+  end
+
+  return ids
+end
+
+private
+NAME_CACHE = {}

data/plugins/util/plugin.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0"?>
+<plugin>
+  <id>util</id>
+  <version>1</version>
+  <name>Util</name>
+  <description>Adds utility methods for plugins.</description>
+  <authors>
+    <author>Major</author>
+  </authors>
+  <scripts>
+    <script>command.rb</script>
+    <script>intercept.rb</script>
+    <script>item-on-item-intercept.rb</script>
+    <script>name-lookup.rb</script>
+  </scripts>
+  <dependencies /> <!-- This plugin should _NOT_ depend on anything. -->
+</plugin>