52 lines
1.4 KiB
Elixir
52 lines
1.4 KiB
Elixir
defmodule Blanks do
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def replace([do: ast], replacements), do: [do: replace(ast, replacements)]
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def replace(ast, replacements) do
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replacements = List.wrap(replacements)
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ast
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|> Macro.prewalk(replacements, &pre/2)
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|> elem(0)
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end
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defp pre({:assert_receive, _, args} = node, replacements) do
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{args, replacements} = Macro.prewalk(args, replacements, &pre_pin/2)
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{put_elem(node, 2, args), replacements}
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end
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defp pre({:___, _, _}, [first | remainder]), do: {first, remainder}
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defp pre(node, acc), do: {node, acc}
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defp pre_pin({:___, _, _}, [first | remainder]), do: {pin(first), remainder}
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defp pre_pin(node, acc), do: {node, acc}
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defp pin(var) when is_tuple(var) do
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quote do
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^unquote(var)
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end
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end
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defp pin(var), do: var
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def count(ast) do
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ast
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|> Macro.prewalk(0, &count/2)
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|> elem(1)
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end
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defp count({:___, _, _} = node, acc), do: {node, acc+1}
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defp count(node, acc), do: {node, acc}
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def replace_line([do: ast], replacement_fn), do: [do: replace_line(ast, replacement_fn)]
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def replace_line({:__block__, meta, lines}, replacement_fn) do
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replaced_lines = Enum.map(lines, fn(line) ->
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replace_line(line, replacement_fn)
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end)
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{:__block__, meta, replaced_lines}
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end
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def replace_line(line, replacement_fn) do
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if count(line) > 0 do
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replacement_fn.(line)
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else
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line
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end
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end
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end
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