php - What does this do? -

I have ever used $ ret = NTTTT & lt; Div id = "toptabs" & gt; '; or anything else, it seems that it could throw a parse error ... can someone explain why this does not happen?

  Public function rendersTabs () {if (empty ($ it- & gt; current tabs)) {return "'; } $ Ret = N.T.T.T.T.T. '& Lt; Div id = "toptabs" & gt; '; If (empty! ($ This- & gt; current tabs ['left'])) {$ ret. = $ This- & gt; DoTabs ($ this-> Current Tabs ['left'], 'left'); } If (empty! ($ This- & gt; current tabs ['right'])) {$ ret. = $ This- & gt; DoTabs ($ this- & gt; current tab ['right'], 'right'); } $ Ret = N.T.T.T.T.T.T. '& Lt; / Div & gt; '; Return $ ret; } 
 
 I think it's defined anywhere to point to these new rows and tabs Are there. / P> 
  define ("t", "\ t"); Define ("n", "\ r \ n");