Class: TwitterToCsv::BoolWordFieldParser

Inherits:
Object
  • Object
show all
Defined in:
lib/twitter_to_csv/bool_word_field_parser.rb

Constant Summary collapse

TOKEN_SEPARATOR = 
/[^a-zA-Z0-9-]+/

Class Method Summary collapse

Class Method Details

.check(pattern, text) ⇒ Object 



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# File 'lib/twitter_to_csv/bool_word_field_parser.rb', line 45

def self.check(pattern, text)
  logic = pattern[:logic]
  tokens = text.downcase.split(TOKEN_SEPARATOR).reject {|t| t.length == 0 }.join(" ")
  !!descend_check(logic, tokens)
end

.descend_check(logic, tokens) ⇒ Object 



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# File 'lib/twitter_to_csv/bool_word_field_parser.rb', line 51

def self.descend_check(logic, tokens)
  if logic.is_a?(String)
    # See if the token(s) are present.
    tokens =~ /\b#{Regexp::escape logic}\b/
  elsif logic.length == 1
    # Recurse further.
    descend_check logic.first, tokens
  elsif logic.length == 3
    # Apply the given logical operation.
    first = descend_check(logic.first, tokens)
    last = descend_check(logic.last, tokens)
    if logic[1] == :and
      first && last
    elsif logic[1] == :or
      first || last
    else
      raise InvalidLogicError.new("Unknown operation: #{logic[1]}")
    end
  else
    raise InvalidLogicError.new("Invalid expression length of #{logic.length}")
  end
end

.descend_parse(struct, tokens) ⇒ Object 



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# File 'lib/twitter_to_csv/bool_word_field_parser.rb', line 18

def self.descend_parse(struct, tokens)
  while tokens.length > 0
    token = tokens.shift
    if token == ")"
      return
    elsif token == "("
      if struct.length > 0
        sub_struct = []
        struct << sub_struct
        descend_parse(sub_struct, tokens)
      end
    elsif %w[AND OR].include?(token)
      sub_struct = []
      struct << :and if token == "AND"
      struct << :or if token == "OR"
      struct << sub_struct
      descend_parse(sub_struct, tokens)
    else
      if struct[0]
        struct[0] += " " + token.downcase
      else
        struct << token.downcase
      end
    end
  end
end

.parse(string) ⇒ Object 



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# File 'lib/twitter_to_csv/bool_word_field_parser.rb', line 9

def self.parse(string)
  parts = string.split(":")
  name = parts.shift
  tokens = parts.join(":").gsub(/\)/, " ) ").gsub(/\(/, " ( ").split(/\s+/).reject {|s| s.length == 0 }
  struct = []
  descend_parse(struct, tokens)
  { :name => name, :logic => struct }
end