105 lines
2.1 KiB
Lua
105 lines
2.1 KiB
Lua
local M = {}
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local stateMeta
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local function are_both_states(a, b)
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return a.is_state and b.is_state
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end
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stateMeta = {
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__tostring = function(v)
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return v.name
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end,
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__le = function(self, other)
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if not are_both_states(self, other) then
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return false
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end
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return self.idx <= other.idx
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end,
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__lt = function(self, other)
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if not are_both_states(self, other) then
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return false
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end
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return self.idx < other.idx
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end,
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__index = function(self, name)
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if name == 'is_state' then
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return true
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end
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end
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}
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function M.build_states(defs)
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local states = {}
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for i, name in ipairs(defs) do
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local state = setmetatable({ idx = i, name = name }, stateMeta)
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states[i] = state
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states[name] = state
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end
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return states
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end
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local SM = {}
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local function empty_fn()
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end
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function SM:run_enter_state(state)
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local enter_fn = self.defs.enter and self.defs.enter[state] or empty_fn
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enter_fn(self.state)
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end
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function SM:run_exit_state(state)
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local enter_fn = self.defs.exit and self.defs.exit[state] or empty_fn
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enter_fn(self.state)
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end
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local function wrap_state_array(val)
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return val.is_state and { val } or val
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end
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local function canonicalize_event(event)
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return {
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from = wrap_state_array(event.from),
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to = event.to,
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transition = event.transition or function() end,
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}
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end
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function M.build(states, defs)
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local machine = {
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state = states[1],
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defs = defs,
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}
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local prototype = {}
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for name, infos in pairs(defs.events) do
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local event = canonicalize_event(infos)
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prototype[name] = function(self)
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if not vim.list_contains(event.from, self.state) then
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return false
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end
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local previous = self.state
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self:run_exit_state(previous)
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self.state = event.to
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event.transition(previous, self.state)
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self:run_enter_state(self.state)
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return true
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end
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end
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local ret = setmetatable(machine, { __index = vim.tbl_extend('error', SM, prototype)})
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ret:run_enter_state(states[1])
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return ret
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end
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local State = M.build_states {
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'NotLoaded',
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'Shimed',
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'Inited',
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'Imported',
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'Loaded',
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}
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return M
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