There are two state machine libraries you should probably check out, but this is a pretty straight forward implementation of a functional state machine without dependencies.
- gen_fsm
- machinery
brew install elixir
mix deps.get # build dependencies
mix docs # builds documentation for this project
open doc/index.html
open doc/Res.Machine.html
open doc/Res.State.html
mix test
This is a simple example of dynamically create-able state machines.
It supports:
- creating state machines in JSON (priv/example.json)
- transitions
- tracking errors on transitions
- pluggable transition logger (very simple: stdout, memory) Set to memory
It doesn't support:
- callbacks
- named transition (currently open => reserved, instead of passing a verb like "book" to book the room)
- validating states/transition names (if you have a state named "open" but put a transition to value of "opne")
Run this script to simulate a state for a single room:
iex -S mixmix is the build tool
iex is the repl
In the context above you are loading the build tool (which compile the app) into a repl for you to interact with it.
Res.Logger.Memory.start_link() # This will start the memory store
machine = Res.Machine.parse("priv/example.json")
state = Res.Machine.init(machine)
IO.puts state.current_state
{:ok, state} = Res.Machine.transition(state, machine, "reserved")
IO.puts state.current_state
{:ok, state} = Res.Machine.transition(state, machine, "in use")
IO.puts state.current_state
IO.puts state.previous_state
# This will fail
{:error, state} = Res.Machine.transition(state, machine, "reserved")
IO.puts state.current_state
IO.puts state.error
IO.puts Res.State.valid?(state)
Res.Logger.Memory.list()