events

build.lua

@@ -151,7 +151,7 @@ function building_lib.build(mapblock_pos, playername, building_name, rotation, c
 	end)
 
 	placement.place(placement, mapblock_pos, building_def, rotation, callback)
-
+	building_lib.fire_event("placed", mapblock_pos, playername, building_def, rotation)
 	return true
 end
 

events.lua

@@ -0,0 +1,18 @@
+
+-- name -> list<fn>
+local events = {}
+
+function building_lib.fire_event(name, ...)
+    for _, fn in ipairs(events[name] or {}) do
+        fn(...)
+    end
+end
+
+function building_lib.register_on(name, fn)
+    local list = events[name]
+    if not list then
+        list = {}
+        events[name] = list
+    end
+    table.insert(list, fn)
+end

events.spec.lua

@@ -0,0 +1,16 @@
+
+mtt.register("events", function(callback)
+
+    local success = false
+
+    building_lib.register_on("my_event", function(x,y)
+        if x == 1 and y == 2 then
+            success = true
+        end
+    end)
+
+    building_lib.fire_event("my_event", 1, 2)
+
+    assert(success)
+    callback()
+end)

init.lua

@@ -19,9 +19,11 @@ dofile(MP .. "/build.lua")
 dofile(MP .. "/remove.lua")
 dofile(MP .. "/chat.lua")
 dofile(MP .. "/tools.lua")
+dofile(MP .. "/events.lua")
 dofile(MP .. "/mapgen.lua")
 
 if minetest.get_modpath("mtt") and mtt.enabled then
+	dofile(MP .. "/events.spec.lua")
 	dofile(MP .. "/conditions.spec.lua")
 	dofile(MP .. "/build.spec.lua")
 end

readme.md

@@ -84,10 +84,19 @@ building_lib.register_condition("on_flat_surface", {
 })
 ```
 
+## Conditions
+
 Built-in conditions:
 * `group=<groupname>` checks if there is already a building with the specified groupname
 * `on_group=<groupname>` checks if there is a building with the specified groupname below
 
+## Events
+
+```lua
+building_lib.register_on("placed", function(mapblock_pos, playername, building_def, rotation) end)
+building_lib.register_on("removed", function(mapblock_pos, playername, building_info) end)
+```
+
 ## Chat commands
 
 * `/building_info`

remove.lua

@@ -13,7 +13,7 @@ function building_lib.can_remove(mapblock_pos)
     return true
 end
 
-function building_lib.remove(mapblock_pos)
+function building_lib.remove(mapblock_pos, playername)
     local success, err = building_lib.can_remove(mapblock_pos)
     if not success then
         return success ,err
@@ -34,5 +34,6 @@ function building_lib.remove(mapblock_pos)
         end
     end
 
+    building_lib.fire_event("removed", mapblock_pos, playername, building_info)
     return true
 end