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101 lines
2 KiB
Elixir
101 lines
2 KiB
Elixir
defmodule Search.Lexer do
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import NimbleParsec
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defp to_number(input), do: Search.Helpers.to_number(input)
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float =
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optional(ascii_char('-+'))
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|> ascii_string([?0..?9], min: 1)
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|> optional(ascii_char('.') |> ascii_string([?0..?9], min: 1))
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|> reduce({List, :to_string, []})
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|> reduce(:to_number)
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l_and =
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choice([string("AND"), string("&&"), string(",")])
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|> unwrap_and_tag(:and)
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l_or =
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choice([string("OR"), string("||")])
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|> unwrap_and_tag(:or)
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l_not =
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choice([string("NOT"), string("!"), string("-")])
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|> unwrap_and_tag(:not)
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lparen = string("(") |> unwrap_and_tag(:lparen)
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rparen = string(")") |> unwrap_and_tag(:rparen)
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space =
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choice([string(" "), string("\t"), string("\n"), string("\r"), string("\v"), string("\f")])
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|> ignore()
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quot = string("\"")
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boost =
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ignore(string("^"))
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|> concat(float)
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|> unwrap_and_tag(:boost)
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stop_words =
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repeat(space)
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|> choice([
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l_and,
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l_or,
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rparen,
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boost
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])
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defcombinatorp(
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:dirty_text,
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lookahead_not(stop_words)
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|> choice([
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string("\\") |> utf8_char([]),
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string("(") |> parsec(:dirty_text) |> string(")"),
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utf8_char(not: ?(..?))
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])
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|> times(min: 1)
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)
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text =
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parsec(:dirty_text)
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|> reduce({List, :to_string, []})
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|> unwrap_and_tag(:term)
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|> label("a term, like `safe'")
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quoted_text =
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ignore(quot)
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|> repeat(choice([
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ignore(string("\\")) |> string("\""),
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ignore(string("\\")) |> string("\\"),
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string("\\") |> utf8_char([]),
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utf8_char(not: ?")
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]))
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|> ignore(quot)
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|> reduce({List, :to_string, []})
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|> unwrap_and_tag(:term)
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|> label(~s|a term enclosed in quotes, like `"/)^3^(\\\\"'|)
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term =
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choice([
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quoted_text,
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text
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])
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outer =
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choice([
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l_and,
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l_or,
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l_not,
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lparen,
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rparen,
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boost,
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space,
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term
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])
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search =
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repeat(outer)
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|> eos()
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defparsec :lex, search
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end
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