Added State Change Callback Functions

Each state now has an OnOpen and OnClose callback function. These are available to be set by the client but not required. If not set, they will be ignored.

loveframes/libraries/utils.lua

@@ -5,18 +5,74 @@
 
 return function(loveframes)
 ---------- module start ----------
-
 -- util library
 --local util = {}
 
+local statecallbacks = {};
+
 --[[---------------------------------------------------------
 	- func: SetState(name)
 	- desc: sets the current state
 --]]---------------------------------------------------------
 function loveframes.SetState(name)
 
-	loveframes.state = name
+	if (loveframes.state ~= name) then
-	loveframes.base.state = name
+
+		--fire the closing function of the soon-to-be-closed state
+		if (type(statecallbacks[loveframes.state]) == "table" and
+			type(statecallbacks[loveframes.state].onclose) == "function") then
+			--callback must accept the name of the current state and soon-to-be-opened state as args
+			statecallbacks[loveframes.state].onclose(loveframes.state, name);
+		end
+
+		local oldstate = loveframes.state;
+		loveframes.state = name
+		loveframes.base.state = name
+
+		--fire the opening function of the newly-opened state
+		if (type(statecallbacks[loveframes.state]) == "table" and
+			type(statecallbacks[loveframes.state].onopen) == "function") then
+			--callback must accept the name of the current state and previous state as args
+			statecallbacks[loveframes.state].onopen(name, oldstate);
+		end
+
+	end
+
+end
+
+--[[---------------------------------------------------------
+	- func: SetStateOnOpenCallback(name, func)
+	- desc: sets a state's opening callback function
+--]]---------------------------------------------------------
+function loveframes.SetStateOnOpenCallback(name, func)
+
+	if (type(name) == "string" and name:gsub("%s", '') ~= '' and
+		type(func) == "function") then
+
+		if (not (statecallbacks[name])) then
+			statecallbacks[name] = {};
+		end
+
+		statecallbacks[name].onopen = func;
+	end
+
+end
+
+--[[---------------------------------------------------------
+	- func: SetStateOnOpenCallback(name, func)
+	- desc: sets a state's closing callback function
+--]]---------------------------------------------------------
+function loveframes.SetStateOnCloseCallback(name, func)
+
+	if (type(name) == "string" and name:gsub("%s", '') ~= '' and
+		type(func) == "function") then
+
+		if (not (statecallbacks[name])) then
+			statecallbacks[name] = {};
+		end
+
+		statecallbacks[name].onclose = func;
+	end
 
 end