Class: RuboCop::StringInterpreter

Relationships & Source Files
Inherits:	Object
Defined in:	lib/rubocop/string_interpreter.rb

Overview

Take a string with embedded escapes, and convert the escapes as the Ruby interpreter would when reading a double-quoted string literal. For example, "\\n" will be converted to "\n".

Constant Summary

STRING_ESCAPES = private
# File 'lib/rubocop/string_interpreter.rb', line 8

{
  '\a' => "\a", '\b' => "\b", '\e' => "\e", '\f' => "\f", '\n' => "\n",
  '\r' => "\r", '\s' => ' ',  '\t' => "\t", '\v' => "\v", "\\\n" => ''
}.freeze

STRING_ESCAPE_REGEX = private
# File 'lib/rubocop/string_interpreter.rb', line 12

/\\(?:
  [abefnrstv\n]     |   # simple escapes (above)
  \d{1,3}           |   # octal byte escape
  x[0-9a-fA-F]{1,2} |   # hex byte escape
  u[0-9a-fA-F]{4}   |   # unicode char escape
  u\{[^}]*\}        |   # extended unicode escape
  .                     # any other escaped char
)/x.freeze

Class Method Details

.interpret(string)

[ GitHub ]

# File 'lib/rubocop/string_interpreter.rb', line 24


def interpret(string)
  # We currently don't handle \cx, \C-x, and \M-x
  string.gsub(STRING_ESCAPE_REGEX) do |escape|
    STRING_ESCAPES[escape] || interpret_string_escape(escape)
  end
end

.interpret_hex(escape) (private)

[ GitHub ]

# File 'lib/rubocop/string_interpreter.rb', line 51


def interpret_hex(escape)
  [escape[2..].hex].pack('C')
end

.interpret_octal(escape) (private)

[ GitHub ]

# File 'lib/rubocop/string_interpreter.rb', line 55


def interpret_octal(escape)
  [escape[1..].to_i(8)].pack('C')
end

.interpret_string_escape(escape) (private)

[ GitHub ]

# File 'lib/rubocop/string_interpreter.rb', line 33


def interpret_string_escape(escape)
  case escape[1]
  when 'u'  then interpret_unicode(escape)
  when 'x'  then interpret_hex(escape)
  when /\d/ then interpret_octal(escape)
  else
    escape[1] # literal escaped char, like \\
  end
end

.interpret_unicode(escape) (private)

[ GitHub ]

# File 'lib/rubocop/string_interpreter.rb', line 43


def interpret_unicode(escape)
  if escape[2] == '{'
    escape[3..].split(/\s+/).map(&:hex).pack('U*')
  else
    [escape[2..].hex].pack('U')
  end
end