Class: Minjs::ECMA262::ExpLogicalNot

Inherits:
Expression show all
Includes:
UnaryOperation
Defined in:
lib/minjs/ecma262/expression.rb

Overview

Class of the Logical Not operator expression element.

See Also:

Instance Attribute Summary

Attributes included from UnaryOperation

#val

Attributes inherited from Base

#parent

Instance Method Summary collapse

Methods included from UnaryOperation

#==, #add_paren, #deep_dup, #remove_paren, #replace, #side_effect?, #to_js, #traverse

Methods inherited from Expression

#left_hand_side_exp?, #side_effect?

Methods inherited from Base

#==, #add_remove_paren, #concat, #deep_dup, #replace, #to_js, #traverse

Constructor Details

#initialize(val) ⇒ ExpLogicalNot

Returns a new instance of ExpLogicalNot.



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# File 'lib/minjs/ecma262/expression.rb', line 1076

def initialize(val)
  @val = val
end

Instance Method Details

#ecma262_typeof ⇒ Symbol

return results of ‘typeof’ operator.

Returns:

  • (Symbol) —

    :boolean



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# File 'lib/minjs/ecma262/expression.rb', line 1143

def ecma262_typeof
  :boolean
end

#priority ⇒ Fixnum

Returns expression priority.

Returns:

  • (Fixnum) —

    expression priority



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# File 'lib/minjs/ecma262/expression.rb', line 1086

def priority
  PRIORITY_UNARY
end

#reduce(parent) ⇒ Object

reduce expression if available

Parameters:

  • parent (Base) —

    parent element



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# File 'lib/minjs/ecma262/expression.rb', line 1092

def reduce(parent)
  if @val.kind_of? ECMA262Numeric and (@val.to_js == "0" || @val.to_js == "1")
    return
  end

  if (e = to_ecma262_boolean) != nil and @val.side_effect? == false
    if e
      parent.replace(self, ExpLogicalNot.new(ECMA262Numeric.new(0)))
    else
      parent.replace(self, ExpLogicalNot.new(ECMA262Numeric.new(1)))
    end
  elsif @val.kind_of? ExpLogicalNot and
     @val.val.respond_to?(:ecma262_typeof) and
     @val.val.ecma262_typeof == :boolean
      parent.replace(self, @val.val)
  end
end

#sym ⇒ Object

symbol of expression



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# File 'lib/minjs/ecma262/expression.rb', line 1081

def sym
  "!"
end

#to_ecma262_boolean ⇒ Boolean

Returns results of ToBoolean()

Returns true or false if trivial, otherwise nil.

Returns:

See Also:



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# File 'lib/minjs/ecma262/expression.rb', line 1118

def to_ecma262_boolean
  return nil unless @val.respond_to? :to_ecma262_boolean
  return nil if @val.to_ecma262_boolean.nil?
  !@val.to_ecma262_boolean
end

#to_ecma262_number ⇒ Numeric

Returns results of ToNumber()

Returns number if value is trivial, otherwise nil.

Returns:

  • (Numeric)

See Also:



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# File 'lib/minjs/ecma262/expression.rb', line 1132

def to_ecma262_number
  if @val.respond_to? :to_ecma262_number
    v = @val.to_ecma262_number
    return nil if v.nil?
    v == 0 ? 1 : 0
  end
end