# indent w/ 2 spaces
source: |
  2+2;
  2**2;
  x << y;
reference: |
  program
    statementOrScope
      statement
        expressionStatement
          expression
            expression
              2
            +
            expression
              2
          ;
    statementOrScope
      statement
        expressionStatement
          expression
            expression
              2
            **
            expression
              2
          ;
    statementOrScope
      statement
        expressionStatement
          expression
            expression
              x
            <<
            expression
              y
          ;
    <EOF>
