54 lines
1 KiB
Elixir
54 lines
1 KiB
Elixir
defmodule Parser do
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@doc """
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Parse file with instructions.
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"""
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def parse_file(filepath) do
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File.stream!(filepath)
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|> Stream.map(&String.trim_trailing/1)
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|> Enum.to_list()
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|> parse_input()
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end
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@doc """
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Parse instructions.
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# Examples:
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iex> Parser.parse_input(["LLR", "", "AAA = (AAA, ZZZ)", "ZZZ = (ZZZ, ZZZ)"])
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{["L", "L", "R"], %{"AAA" => ["AAA", "ZZZ"], "ZZZ" => ["ZZZ", "ZZZ"]}}
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"""
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def parse_input(lines) do
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instructions =
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lines
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|> hd()
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|> String.graphemes()
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steps =
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lines
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|> Stream.drop(2)
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|> Stream.map(&parse_instruction/1)
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|> Map.new()
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{instructions, steps}
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end
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@doc """
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Parse instruction string.
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## Examples
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iex> Parser.parse_instruction("BBB = (AAA, ZZZ)")
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{"BBB", ["AAA", "ZZZ"]}
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"""
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def parse_instruction(src) do
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[key, tuple] = String.split(src, " = ")
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destinations =
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tuple
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|> String.slice(1..-2//1)
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|> String.split(", ")
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{key, destinations}
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end
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end
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