Class: Rubocop::Cop::HashLiteral

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/hash_literal.rb

Constant Summary collapse

ERROR_MESSAGE = 
'Use hash literal {} instead of Hash.new.'

Instance Attribute Summary

Attributes inherited from Cop

#correlations, #debug, #disabled_lines, #offences

Instance Method Summary collapse

Methods inherited from Cop

#add_offence, cop_name, #has_report?, inherited, #initialize, #name

Constructor Details

This class inherits a constructor from Rubocop::Cop::Cop

Instance Method Details

#inspect(file, source, tokens, sexp) ⇒ Object 



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# File 'lib/rubocop/cop/hash_literal.rb', line 8

def inspect(file, source, tokens, sexp)
  offences = preliminary_scan(sexp)

  # find Hash.new()
  each(:method_add_arg, sexp) do |s|
    next if s[1][0] != :call

    receiver = s[1][1][1]
    method_name = s[1][3][1]

    if receiver && receiver[1] == 'Hash' &&
        method_name == 'new' && s[2] == [:arg_paren, nil]
      offences.delete(Offence.new(:convention,
                                  receiver[2].lineno,
                                  ERROR_MESSAGE))
      add_offence(:convention,
                  receiver[2].lineno,
                  ERROR_MESSAGE)
    end

    # check for false positives
    if receiver && receiver[1] == 'Hash' &&
        method_name == 'new' && s[2] != [:arg_paren, nil]
      offences.delete(Offence.new(:convention,
                                  receiver[2].lineno,
                                  ERROR_MESSAGE))
    end
  end

  offences.each { |o| add_offence(*o.explode) }
end

#preliminary_scan(sexp) ⇒ Object 



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# File 'lib/rubocop/cop/hash_literal.rb', line 40

def preliminary_scan(sexp)
  offences = []

  # find Hash.new
  # there will be some false positives here, which
  # we'll eliminate later on
  each(:call, sexp) do |s|
    receiver = s[1][1]

    if receiver && receiver[1] == 'Hash' &&
        s[3][1] == 'new'
      offences << Offence.new(:convention,
                              receiver[2].lineno,
                              ERROR_MESSAGE)
    end
  end

  offences
end