Manuel Simon Hirsig
78 lines
2.8 KiB
Lua
78 lines
2.8 KiB
Lua
local setfenv, rawget, rawset, setmetatable, mask, g = setfenv, rawget, rawset, setmetatable, bit.band, getfenv(0)
|
|
local DECLARED, ACCESSOR, MUTABLE, PUBLIC = 1, 2, 4, 8
|
|
local ACCESSOR_KEY, MUTABLE_KEY, PUBLIC_KEY = 'accessor', 'mutable', 'public'
|
|
local PROPERTY = {[ACCESSOR_KEY]=ACCESSOR, [MUTABLE_KEY]=MUTABLE, [PUBLIC_KEY]=PUBLIC}
|
|
local _data, _metadata, _modifier_properties = {}, {}, {}
|
|
|
|
local metadata_mt = {
|
|
__index=function() return 0 end,
|
|
__newindex=function(self, key, value)
|
|
if rawget(self, key) then error('Duplicate key "'..key..'".', 2) end
|
|
rawset(self, key, value)
|
|
end,
|
|
}
|
|
local env_mt = {
|
|
__metatable = false,
|
|
__index = function(self, key)
|
|
local value, properties = _data[self][key], _metadata[self][key]
|
|
if mask(DECLARED+ACCESSOR, properties) == DECLARED then
|
|
return value
|
|
elseif mask(ACCESSOR, properties) == ACCESSOR then
|
|
return value(key)
|
|
else
|
|
return g[key] or error('No key "'..key..'".', 2)
|
|
end
|
|
end,
|
|
__newindex = function(self, key, value)
|
|
local properties = _metadata[self][key]
|
|
if properties == 0 then
|
|
_metadata[self][key] = DECLARED
|
|
-- elseif mask(MUTABLE, properties) == 0 then
|
|
-- error('"'..key..'" is immutable.', 2)
|
|
end
|
|
_data[self][key] = value
|
|
end,
|
|
}
|
|
local interface_mt = {
|
|
__metatable = false,
|
|
__index = function(self, key)
|
|
local value, properties = _data[self][key], _metadata[self][key]
|
|
if mask(ACCESSOR+PUBLIC, properties) == PUBLIC then
|
|
return value
|
|
elseif mask(PUBLIC, properties) == PUBLIC then
|
|
return value(key)
|
|
else
|
|
error('No key "'..key..'".', 2)
|
|
end
|
|
end,
|
|
__newindex = function(self, key, value) self[key](value) end,
|
|
}
|
|
local modifier_mt = {
|
|
__metatable = false,
|
|
__index = function(self, key)
|
|
local property = PROPERTY[key]
|
|
if not property then error('Unsupported modifier "'..key..'".', 2) end
|
|
if mask(property, _modifier_properties[self]) ~= 0 then error('Duplicate modifier "'..key..'".', 2) end
|
|
_modifier_properties[self] = _modifier_properties[self] + property
|
|
return self
|
|
end,
|
|
__newindex = function(self, key, value)
|
|
_data[self][key] = value
|
|
_metadata[self][key] = _modifier_properties[self]
|
|
end,
|
|
}
|
|
function g.aux_module()
|
|
local data, metadata, modifier, env, interface
|
|
modifier = setmetatable({}, modifier_mt) env = setmetatable({}, env_mt) interface = setmetatable({}, interface_mt)
|
|
local function modifier_accessor(key) _modifier_properties[modifier] = DECLARED+PROPERTY[key] return modifier end
|
|
data = {g=g, m=env, [ACCESSOR_KEY]=modifier_accessor, [MUTABLE_KEY]=modifier_accessor, [PUBLIC_KEY]=modifier_accessor}
|
|
metadata = setmetatable({g=DECLARED, m=DECLARED, [ACCESSOR_KEY]=ACCESSOR, [MUTABLE_KEY]=ACCESSOR, [PUBLIC_KEY]=ACCESSOR}, metadata_mt)
|
|
|
|
_data[modifier], _data[env], _data[interface] = data, data, data
|
|
_metadata[modifier], _metadata[env], _metadata[interface] = metadata, metadata, metadata
|
|
|
|
env.mutable.__ = nil
|
|
|
|
setfenv(2, env)
|
|
return interface
|
|
end |