code: @Override
  	public Value execute(String line, DBGPReader dbgp) throws Exception
  	{
  		PExp expr = parseExpression(line, getDefaultName());
  		Environment env = getGlobalEnvironment();
  		Environment created = new FlatCheckedEnvironment(assistantFactory, createdDefinitions.asList(), env, NameScope.NAMESANDSTATE);
  
  		typeCheck(expr, created);
  		return execute(expr, dbgp);
  	}
docs: Parse the line passed, type check it and evaluate it as an expression in the initial context.
  
  @param line
  A VDM expression.
  @return The value of the expression.
  @throws Exception
  Parser, type checking or runtime errors.