anchor.diff:  statementContents returns [r]
       : e=expression      { r = e }
       | i=importStatement { r = i }
  -;
  -
  -functionCall returns [r]
  -    : #(LPAREN f=symbol a=expression) { r = EeyFunctionCall( f, (a,) ) }
   ;
   
   expression returns [r]
  
positive.code:     | f=functionCall { r = f }
  ;
  
  symbol returns [r]
      : f:SYMBOL { r = EeySymbol( f.getText() ) }
  ;
  
negative.code:     : #("if" pred=expression COLON s=suite) { r = EeyIf( pred, s ) }
  ;
  
  functionCall returns [r]
      : #(LPAREN f=symbol a=expression) { r = EeyFunctionCall( f, (a,) ) }
  ;
  
  suite returns [r]
      : #(INDENT NEWLINE s=statement DEDENT) { r = ( s, ) }
  ;
  
  