code: function ( nodes ) {
  			var form = nodes[0],
  				word = nodes[1];
  
  			return word && form && this.language.convertGrammar( word, form );
  		}
docs: Transform parsed structure into grammar conversion. Invoked by
  putting {{grammar:form|word}} in a message
  
  @param {Array} nodes List [{Grammar case eg: genitive}, {String word}]
  @return {String} selected grammatical form according to current
  language.