RiGrammar rg = new RiGrammar(this, "mygrammar.g");
    System.out.println(rg.expand());

    {
      <start>
      <rule1> | <rule2> | <rule3>
    }

    {
      <rule2>
      terminal1 | 
      terminal2 | <rule1>
      # this is a comment 
    }
    ...

• expand() which simply begins at the <start> state and generates a string of terminals from the grammar.

• expandFrom(String) which begins with the argument String (which can consist of both non-terminals and terminals,) and expands from there. Notice that expand() is simply a convenient version of expandFrom("<start>");.

• expandWith(String, String) takes 2 String arguments, the 1st (a terminal) is guaranteed to be substituted for the 2nd (a non-terminal). Once this subsitution is made, the algorithm then works backwards (up the tree from the leaf) ensuring that the terminal (arg1) appears in the output string. For example, with the grammar fragment above, one might call:

        grammar.expandWith("hello", "<rule2>");
   

  assuring not only that <rule2>will be used at least once in the generation process, but that when it is, it will be replaced by the terminal "hello".

• Grammar files should be placed in the 'data' directory of a processing sketch, along with images, fonts, and other resources.

• A RiGrammar object will assign (by default) equal weights to all choices in a rule. One can adjust the weights by adding 'multipliers' as follows: (in the rule below, 'terminal1' will be chosen twice as often as the 2 other choices.

     {
       <rule2>
       [2] terminal1 | 
       terminal2 | <rule1> 
     }

• The RiGrammar object supports callbacks, from your grammar, back into your Java code. To generate a callback, add a method call in your grammar, surrounded by back-ticks, as follows:

     
       {
         <rule2>
         The cat ran after the `getRhyme("cat");` |
         The <noun> ran after the `pluralize(<noun>);` 
       }

  Any number of arguments may be passed in a callback, but for each call, there must be a corresponding method(with the same number and type or arguments) in the sketch, e.g.,

      String pluralize(String s) {
        ...
      }
   

  As of v81, the exec mechanism is enabled by default, so calls to setExecEnabled() are no longer necessary.

RiGrammar(parent, grammarFileName);
RiGrammar(parent);