Class: Opal::Nodes::StringNode

Inherits:
Base
  • Object
show all
Defined in:
opal/lib/opal/nodes/literal.rb

Constant Summary collapse

ESCAPE_CHARS =
{
  'a' => '\\u0007',
  'e' => '\\u001b'
}.freeze
ESCAPE_REGEX =
/(\\+)([#{ ESCAPE_CHARS.keys.join('') }])/

Instance Attribute Summary

Attributes inherited from Base

#compiler, #type

Instance Method Summary collapse

Methods inherited from Base

#add_gvar, #add_ivar, #add_local, #add_temp, #children, children, #class_variable_owner, #class_variable_owner_nesting_level, #comments, #compile_to_fragments, #error, #expr, #expr?, #expr_or_nil, #fragment, handle, handlers, #has_rescue_else?, #helper, #in_ensure, #in_ensure?, #in_while?, #initialize, #process, #push, #recv, #recv?, #s, #scope, #stmt, #stmt?, truthy_optimize?, #unshift, #while_loop, #with_temp, #wrap

Methods included from Helpers

#conditional_send, #current_indent, #empty_line, #indent, #js_falsy, #js_truthy, #js_truthy_optimize, #line, #mid_to_jsid, #property, #valid_name?

Constructor Details

This class inherits a constructor from Opal::Nodes::Base

Instance Method Details

#compileObject


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# File 'opal/lib/opal/nodes/literal.rb', line 56

def compile
  string_value = value
  encoding = string_value.encoding
  should_encode = encoding != Encoding::UTF_8

  sanitized_value = string_value.inspect.gsub(/\\u\{([0-9a-f]+)\}/) do
    code_point = Regexp.last_match(1).to_i(16)
    to_utf16(code_point)
  end
  push translate_escape_chars(sanitized_value)

  if should_encode && RUBY_ENGINE != 'opal'
    push '.$force_encoding("', encoding.name, '")'
  end
end

#to_utf16(code_point) ⇒ Object


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# File 'opal/lib/opal/nodes/literal.rb', line 73

def to_utf16(code_point)
  ten_bits = 0b1111111111
  u = ->(code_unit) { '\\u' + code_unit.to_s(16).upcase }

  return u.call(code_point) if code_point <= 0xFFFF

  code_point -= 0x10000

  # Shift right to get to most significant 10 bits
  lead_surrogate = 0xD800 + (code_point >> 10)

  # Mask to get least significant 10 bits
  tail_surrogate = 0xDC00 + (code_point & ten_bits)

  u.call(lead_surrogate) + u.call(tail_surrogate)
end

#translate_escape_chars(inspect_string) ⇒ Object


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# File 'opal/lib/opal/nodes/literal.rb', line 46

def translate_escape_chars(inspect_string)
  inspect_string.gsub(ESCAPE_REGEX) do |original|
    if Regexp.last_match(1).length.even?
      original
    else
      Regexp.last_match(1).chop + ESCAPE_CHARS[Regexp.last_match(2)]
    end
  end
end