fsm.p8

fsm.lua

do
local function doevent(m,c,e, ...)
  local dst=(c[m.state] and c[m.state][e])
          or (c["*"] and c["*"][e])
  dst = type(dst)=="function" and dst(...) or dst
  if dst then
    m.state=dst
    return dst
  end
end
local function clone(m,init)
  local m2={}
  for e,f in pairs(m) do
    m2[e]=f
  end
  m2.state=init
  return m2
end

_ENV.fsm=function(init,spec)
  local m,c={state=init},{}
  m.clone=function() return clone(m,init) end
  for e,es in pairs(spec) do
    for src,dst in pairs(es) do
      src=split(src)
      for i=1,#src do
        local s=src[i]
        c[s]=c[s] or {}
        c[s][e]=dst
      end
    end
    m[e]=function(sm,...)
      return doevent(sm,c,e,...)
    end
  end
  return m
end
end

local m=fsm("off", {
  turn_on={ off = "red" },
  turn_off={ ["red,green,amber"]= "off" },
  change={ red="green", green="amber", amber="red" },
  set = { ["*"] = function(s) return s end },
})


print(m.state)     -- off
print(m:turn_off())-- nil (still off)
print(m:change())  -- nil (still off)
print(m:turn_on()) -- red
print(m:change())  -- green
print(m:change())  -- amber
print(m:change())  -- red
print(m:turn_on()) -- nil (still amber)
print(m:turn_off())-- off
print(m:change())  -- nil (still off)
print(m:set("green")) -- "green" (jump to state without transition)
print(m:set("blue")) -- "blue" (made-up state)

local m2=m:clone()
print(m2.state)     -- off
print(m2:turn_on()) -- red