anchor.diff:  
   CAPABILITY : 'small' | 'large' | 'database';
   
  -NODE_PARAM : INT_CONST 'of nodes with' CAPABILITY 'from' NODE_CLASSIFIER;
  +ID: ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')*;
   
  -CREATE_STATEMENT : 'Create a new environment called' ID 'using' NODE_PARAM (COMMA_AND NODE_PARAM)*;
  +node_param : INT_CONST CAPABILITY 'nodes from' NODE_CLASSIFIER;
   
  -
  -
  +create_statement : 'Create a new environment called' ID 'using' node_param (COMMA_AND node_param)* '.';
  
positive.code: INT_CONST: '0'..'9'+;
  STRING: '"' (~('\\'|'"') )* '"';
  
  COMMA : ',';
  AND : 'and';
  PERIOD : '.';
  
  COMMA_AND : COMMA | AND | COMMA AND;
  
  //ENVIRONMENT_DEFINITION : 'The' ID 'environment consists of' NODE_APP_MAPPING (COMMA_AND NODE_APP_MAPPING)* PERIOD;
  
  
negative.code: grammar Ngds;
  
  options{
  	language = Java;
  //    backtrack=true;
      output = AST;              // build trees
      ASTLabelType = CommonTree; // use standard tree nodes
  }
  @header{
  	package com.peoplemerge.ngds;
  