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Étienne Reuh Fildadut
e71bff9562
Previous system linked the variable name with the saved value, meaning the variable could not be renamed or moved outside the global scope. Instead we propose to store all persistent values in a global table, identifying each by a key. To still allow nice manipulation with identifiers, the alias syntax replace the persistent syntax for symbols - an aliases symbol will act as if a function call was used in place of the identifier when it appear.
66 lines
1.6 KiB
Lua
66 lines
1.6 KiB
Lua
local ast = require("ast")
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local Nil, Overloadable
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local operator_priority = require("common").operator_priority
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local Definition = ast.abstract.Node {
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type = "definition",
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symbol = nil,
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expression = nil,
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format_priority = operator_priority["_=_"],
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init = function(self, symbol, expression)
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self.symbol = symbol
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self.expression = expression
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end,
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_format = function(self, ...)
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return self.symbol:format(...).." = "..self.expression:format_right(...)
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end,
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traverse = function(self, fn, ...)
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fn(self.symbol, ...)
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fn(self.expression, ...)
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end,
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_eval = function(self, state)
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if self.symbol.exported and state.scope:defined_in_current(self.symbol) then
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return Nil:new() -- export vars: can reuse existing defining
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end
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local symbol = self.symbol:eval(state)
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if symbol.alias then
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state.scope:define_alias(symbol, self.expression)
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else
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local val = self.expression:eval(state)
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if Overloadable:issub(val) then
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state.scope:define_overloadable(symbol, val)
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else
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state.scope:define(symbol, val)
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end
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end
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return Nil:new()
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end,
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_prepare = function(self, state)
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local symbol, val = self.symbol, self.expression
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symbol:prepare(state)
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val:prepare(state)
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if self.symbol.alias then
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state.scope:define(symbol:with{ alias = false }, val) -- disable alias to avoid call in Identifier:_prepare
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elseif Overloadable:issub(val) then
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state.scope:define_overloadable(symbol, val)
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else
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state.scope:define(symbol, val)
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end
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end
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}
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package.loaded[...] = Definition
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Nil, Overloadable = ast.Nil, ast.abstract.Overloadable
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return Definition
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