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31 lines
901 B
Text
31 lines
901 B
Text
local graph = require "./graph"
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type Node<T> = graph.Node<T>
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local create_source_node = graph.create_source_node
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local push_scope_as_child_of = graph.push_scope_as_child_of
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local update_descendants = graph.update_descendants
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export type Source<T> = (() -> T) & ((value: T) -> T)
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local function source<T>(initial_value: T): Source<T>
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local node = create_source_node(initial_value)
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local function update_source(...): T
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if select("#", ...) == 0 then -- no args were given
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push_scope_as_child_of(node)
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return node.cache
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end
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local v = ... :: T
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if node.cache == v and (type(v) ~= "table" or table.isfrozen(v)) then
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return v
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end
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node.cache = v
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update_descendants(node)
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return v
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end
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return update_source
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end
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return source :: (<T>(initial_value: T) -> Source<T>) & (<T>() -> Source<T>)
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