nl_tokens: always returns a TVar ; not a proxied obj
pl_tokens: function ( obj , meta ) { var val , parentId ; if ( undefined === obj || util . isPrimitive ( obj ) ) { return { proxied : obj , raw : obj } ; } val = this . proxiedToTVar . <mask> ( obj ) ; if ( undefined === val ) { val = this . objToTVar . get ( obj ) ; if ( undefined === val ) { this . tVarCount += 1 ; val = new TVar ( this . tVarCount , obj , this ) ; this . proxiedToTVar . set ( val . proxied , val ) ; this . objToTVar . set ( obj , val ) ; this . idToTVar [ val . id ] = val ; this . recordCreation ( val , meta ) ; return val ; } else { // found it in the cache return val ; } } else { // obj was already proxied return val ; } }