anchor.diff:      init/0,
       strlen/2,
       ord/2,
  +    chr/2,
       implode/2,
       implode/3,
       join/2,
  
positive.code: 
  ord(_Context, _Var) ->
      %% TODO: Warning: ord() expects parameter 1 to be string
      null.
  
  -spec implode(Context :: context(), Glue :: var_value(), Pieces :: var_value()) -> binary().
  
negative.code: -spec init() -> [ephp_func:php_function()].
  
  init() -> [
      strlen, ord, chr, implode, join
  ]. 
  
  -spec strlen(Context :: context(), String :: var_value()) -> integer().
  