refactored state machine to be clear about which variables and parameters are state tables, and which are name strings

breaking - changed some property and function names

fixes #16
This commit is contained in:
Max Cahill 2021-07-05 14:53:55 +10:00
parent 1de942daa8
commit b44b92a32d

View File

@ -7,8 +7,8 @@
- a table with enter, exit, update and draw callbacks (all optional)
which each take the state table and varargs as arguments
- a function
which gets passed the current event name, the machine, and varargs as arguments
- a plain function
which gets passed the current event name, the machine table, and varargs as arguments
on changing state, the outgoing state's exit callback is called
then the incoming state's enter callback is called
@ -27,11 +27,11 @@ local path = (...):gsub("state_machine", "")
local class = require(path .. "class")
local state_machine = class()
function state_machine:new(states, start)
function state_machine:new(states, start_in_state)
self = self:init({
states = states or {},
current_state = "",
start_state = start,
current_state_name = "",
reset_state_name = start_in_state or "",
})
self:reset()
@ -39,16 +39,17 @@ function state_machine:new(states, start)
return self
end
--get the current state table (or nil if it doesn't exist)
function state_machine:current_state()
return self.states[self.current_state_name]
end
-------------------------------------------------------------------------------
--internal helpers
function state_machine:_get_state()
return self.states[self.current_state]
end
--make an internal call
function state_machine:_call(name, ...)
local state = self:_get_state()
local state = self:current_state()
if state then
if type(state[name]) == "function" then
return state[name](state, ...)
@ -60,12 +61,12 @@ function state_machine:_call(name, ...)
end
--make an internal call
-- return the call result if it isn't a valid state
-- transition if the return value is a valid state - and return nil if so
-- transition if the return value is a valid state name - and return nil if so
-- return the call result if it isn't a valid state name
function state_machine:_call_and_transition(name, ...)
local r = self:_call(name, ...)
if type(r) == "string" and self:has_state(r) then
self:set_state(r, r == self.current_state)
self:set_state(r, r == self.current_state_name)
return nil
end
return r
@ -75,7 +76,7 @@ end
--various checks
function state_machine:in_state(name)
return self.current_state == name
return self.current_state_name == name
end
function state_machine:has_state(name)
@ -86,13 +87,13 @@ end
--state management
--add a state
function state_machine:add_state(name, data)
function state_machine:add_state(name, state)
if self:has_state(name) then
error("error: added duplicate state "..name)
else
self.states[name] = data
self.states[name] = state
if self:in_state(name) then
self:_call("enter", self)
self:_call_and_transition("enter")
end
end
@ -102,7 +103,7 @@ end
--remove a state
function state_machine:remove_state(name)
if not self:has_state(name) then
error("error: removed missed state "..name)
error("error: removed missing state "..name)
else
if self:in_state(name) then
self:_call("exit")
@ -114,15 +115,16 @@ function state_machine:remove_state(name)
end
--hard-replace a state table
--if do_transitions is truthy and we're replacing the current state,
--exit is called on the old state and enter is called on the new state
function state_machine:replace_state(name, data, do_transitions)
local current = self:in_state(name)
if do_transitions and current then
-- if we're replacing the current state,
-- exit is called on the old state and enter is called on the new state
-- mask_transitions can be used to prevent this if you need to
function state_machine:replace_state(name, state, mask_transitions)
local do_transitions = not mask_transitions and self:in_state(name)
if do_transitions then
self:_call("exit")
end
self.states[name] = data
if do_transitions and current then
self.states[name] = state
if do_transitions then
self:_call_and_transition("enter", self)
end
@ -131,16 +133,16 @@ end
--ensure a state doesn't exist; transition out of it if we're currently in it
function state_machine:clear_state(name)
return self:replace_state(name, nil, true)
return self:replace_state(name, nil)
end
-------------------------------------------------------------------------------
--transitions and updates
--reset the machine to whatever the start state was defined at at creation
--reset the machine state to whatever state was specified at creation
function state_machine:reset()
if self.start_state then
self:set_state(self.start_state, true)
if self.reset_state_name then
self:set_state(self.reset_state_name, true)
end
end
@ -148,10 +150,10 @@ end
-- if the enter callback of the target state returns a valid state name,
-- then it is transitioned to in turn,
-- and so on until the machine is at rest
function state_machine:set_state(state, reset)
if self.current_state ~= state or reset then
function state_machine:set_state(name, reset)
if self.current_state_name ~= name or reset then
self:_call("exit")
self.current_state = state
self.current_state_name = name
self:_call_and_transition("enter", self)
end
return self
@ -172,7 +174,7 @@ function state_machine:draw()
self:_call("draw")
end
--for compatibility when used as a state
--for compatibility when a state machine is nested as a state in another machine
function state_machine:enter(parent)
self.parent = parent
self:reset()