Special variables have a predefined meaning within a computer programming language.



Task

List the special variables used within the language.




/* NetRexx */
options replace format comments java crossref savelog symbols binary
 
class RCSpecialVariables
 
method RCSpecialVariables()
  x = super.toString
  y = this.toString
  say '<super>'x'</super>'
  say '<this>'y'</this>'
  say '<class>'RCSpecialVariables.class'</class>'
  say '<digits>'digits'</digits>'
  say '<form>'form'</form>'
  say '<[1, 2, 3].length>'
  say [1, 2, 3].length
  say '</[1, 2, 3].length>'
  say '<null>'
  say null
  say '</null>'
  say '<source>'source'</source>'
  say '<sourceline>'sourceline'</sourceline>'
  say '<trace>'trace'</trace>'
  say '<version>'version'</version>'
 
  say 'Type an answer:'
  say '<ask>'ask'</ask>'
 
  return
 
method main(args = String[]) public static
 
  RCSpecialVariables()
 
  return
 