nl_tokens: $foo . bar [ 1 ] index求值
pl_tokens: function ( property , baseRef ) { var ast = <mask> . id ; var key ; if ( ast . type === 'references' ) { key = this . getReferences ( ast ) ; } else if ( ast . type === 'integer' ) { key = ast . value ; } else { key = ast . value ; } return baseRef [ key ] ; }