local stage = {}
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-- Mutates an array of nodes and non-tables, unwrapping Paren nodes.
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-- If list_start is given, tail Paren is not unwrapped if it's unpacking and past list_start index.
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local function handle_nodes(nodes, list_start)
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local num_nodes = #nodes
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for index = 1, num_nodes do
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local node = nodes[index]
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if type(node) == "table" then
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local tag = node.tag
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if tag == "Table" or tag == "Return" then
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handle_nodes(node, 1)
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elseif tag == "Call" then
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handle_nodes(node, 2)
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elseif tag == "Invoke" then
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handle_nodes(node, 3)
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elseif tag == "Forin" then
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handle_nodes(node[2], 1)
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handle_nodes(node[3])
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elseif tag == "Local" then
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if node[2] then
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handle_nodes(node[2])
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end
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elseif tag == "Set" then
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handle_nodes(node[1])
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handle_nodes(node[2], 1)
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else
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handle_nodes(node)
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if tag == "Paren" and (not list_start or index < list_start or index ~= num_nodes) then
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local inner_node = node[1]
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if inner_node.tag ~= "Call" and inner_node.tag ~= "Invoke" and inner_node.tag ~= "Dots" then
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nodes[index] = inner_node
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end
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end
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end
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end
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end
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end
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-- Mutates AST, unwrapping Paren nodes.
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-- Paren nodes are preserved only when they matter:
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-- at the ends of expression lists with potentially multi-value inner expressions.
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function stage.run(chstate)
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handle_nodes(chstate.ast)
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end
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return stage
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