Manuel Simon Hirsig
95 lines
3.5 KiB
Lua
95 lines
3.5 KiB
Lua
local tinsert, setfenv, rawget, rawset, setmetatable, mask, g = tinsert, setfenv, rawget, rawset, setmetatable, bit.band, getfenv(0)
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local DECLARED, ACCESSOR, MUTABLE, PUBLIC = 1, 2, 4, 8
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local ACCESSOR_KEY, MUTABLE_KEY, PUBLIC_KEY = 'accessor', 'mutable', 'public'
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local PROPERTY = {[ACCESSOR_KEY]=ACCESSOR, [MUTABLE_KEY]=MUTABLE, [PUBLIC_KEY]=PUBLIC}
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local _data, _metadata, _modifier_properties, _imports, _interfaces = {}, {}, {}, {}, {}
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local metadata_mt = {
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__index=function() return 0 end,
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__newindex=function(self, key, value)
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if rawget(self, key) then error('Duplicate key "'..key..'".', 3) end
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rawset(self, key, value)
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end,
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}
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local env_mt = {
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__metatable = false,
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__index = function(self, key)
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local value, properties = _data[self][key], _metadata[self][key]
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if mask(DECLARED+ACCESSOR, properties) == DECLARED then
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return value
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elseif mask(ACCESSOR, properties) == ACCESSOR then
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return value(key)
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else
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for _, name in _imports[self] do
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local interface = _interfaces[name]
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if interface and mask(PUBLIC, _metadata[interface][key]) ~= 0 then
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return interface[key]
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end
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end
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return g[key] or error('No key "'..key..'".', 2)
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end
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end,
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__newindex = function(self, key, value)
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local properties = _metadata[self][key]
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if properties == 0 then
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_metadata[self][key] = DECLARED
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-- elseif mask(MUTABLE, properties) == 0 then
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-- error('"'..key..'" is immutable.', 2)
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end
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_data[self][key] = value
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end,
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}
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local interface_mt = {
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__metatable = false,
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__index = function(self, key)
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local value, properties = _data[self][key], _metadata[self][key]
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if mask(ACCESSOR+PUBLIC, properties) == PUBLIC then
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return value
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elseif mask(PUBLIC, properties) ~= 0 then
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return value(key)
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else
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error('No key "'..key..'".', 2)
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end
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end,
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__newindex = function(self, key, value) self[key](value) end,
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}
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local modifier_mt = {
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__metatable = false,
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__index = function(self, key)
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local property = PROPERTY[key]
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if not property then error('Unsupported modifier "'..key..'".', 2) end
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if mask(property, _modifier_properties[self]) ~= 0 then error('Duplicate modifier "'..key..'".', 2) end
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_modifier_properties[self] = _modifier_properties[self] + property
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return self
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end,
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__newindex = function(self, key, value)
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_data[self][key] = value
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_metadata[self][key] = _modifier_properties[self]
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end,
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}
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local importer_mt = {
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__call = function(self, ...)
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for i=1,arg.n do
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tinsert(_imports[self], arg[i])
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end
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end,
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}
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function g.aux_module(name)
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if _interfaces[name] then error('Duplicate module "'..name..'".', 2) end
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local data, metadata, imports, importer, modifier, env, interface, modifier_accessor
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modifier, importer, env, interface = setmetatable({}, modifier_mt), setmetatable({}, importer_mt), setmetatable({}, env_mt), setmetatable({}, interface_mt)
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function modifier_accessor(key) _modifier_properties[modifier] = DECLARED+PROPERTY[key] return modifier end
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data = {g=g, m=env, import=importer, [ACCESSOR_KEY]=modifier_accessor, [MUTABLE_KEY]=modifier_accessor, [PUBLIC_KEY]=modifier_accessor}
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metadata = setmetatable({g=DECLARED, m=DECLARED, import=DECLARED, [ACCESSOR_KEY]=ACCESSOR, [MUTABLE_KEY]=ACCESSOR, [PUBLIC_KEY]=ACCESSOR}, metadata_mt)
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imports = {}
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_interfaces[name] = interface
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_data[modifier], _data[env], _data[interface] = data, data, data
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_metadata[modifier], _metadata[env], _metadata[interface] = metadata, metadata, metadata
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_imports[importer], _imports[env] = imports, imports
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env.mutable.__ = nil -- TODO
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setfenv(2, env)
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return interface
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end |