52 lines
1.4 KiB
Text
52 lines
1.4 KiB
Text
defmodule Brace_expansion do
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def getitem(s), do: getitem(String.codepoints(s), 0, [""])
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defp getitem([], _, out), do: {out,[]}
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defp getitem([c|_]=s, depth, out) when depth>0 and (c == "," or c == "}"), do: {out,s}
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defp getitem([c|t], depth, out) do
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x = getgroup(t, depth+1, [], false)
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if (c == "{") and x do
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{y, z} = x
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out2 = for a <- out, b <- y, do: a<>b
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getitem(z, depth, out2)
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else
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if c == "\\" and length(t) > 0 do
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c2 = c <> hd(t)
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getitem(tl(t), depth, Enum.map(out, fn a -> a <> c2 end))
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else
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getitem(t, depth, Enum.map(out, fn a -> a <> c end))
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end
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end
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end
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defp getgroup([], _, _, _), do: nil
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defp getgroup(s, depth, out, comma) do
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{g, s2} = getitem(s, depth, [""])
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if s2 == [] do
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nil
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else
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out2 = out ++ g
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case hd(s2) do
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"}" -> if comma, do: {out2, tl(s2)},
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else: {Enum.map(out2, &"{#{&1}}"), tl(s2)}
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"," -> getgroup(tl(s2), depth, out2, true)
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_ -> getgroup(s2, depth, out2, comma)
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end
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end
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end
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end
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test_cases = ~S"""
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~/{Downloads,Pictures}/*.{jpg,gif,png}
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It{{em,alic}iz,erat}e{d,}, please.
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{,{,gotta have{ ,\, again\, }}more }cowbell!
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{}} some }{,{\\{ edge, edge} \,}{ cases, {here} \\\\\}
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""" |> String.split("\n", trim: true)
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Enum.each(test_cases, fn s ->
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IO.puts s
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Brace_expansion.getitem(s)
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|> elem(0)
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|> Enum.each(fn str -> IO.puts "\t#{str}" end)
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IO.puts ""
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end)
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