title: How to use antlr4 in Eclipse?
body: <p>Since Antlr4 is new version of Antlr and this is the first time I use it. I have downloaded the Antlr4 plugin from eclipse marketplace.
  I made new ANTLR 4 project and I got Hello.g4</p>
  
  <p>Afterward I saw this small grammar:</p>
  
  <pre><code>  /**
    * Define a grammar called Hello
     */
     grammar Hello;
       r  : 'hello' ID ;         // match keyword hello followed by an                                                          identifier
  
        ID : [a-z]+ ;             // match lower-case identifiers
  
         WS : [ \t\r\n]+ -&gt; skip ; // skip spaces, tabs, newlines
  </code></pre>
  
  <p>Once it was saved, It was build and I saw it from the Antlr console, I wanted to test the program but I didn't know how, and I didn't know how to make a new file that can be compiled  by  the new grammar?</p>
  
  <p>Thanks in advance for any help.</p>