For expressions like 3+4 I would like to use the value 7 in an intermediate representation tree. I cannot work out how to get the returns value into a rewrite rule. expression returns [int v]: etc. How do I get expression.v into WR? At the moment I get (+ 3 4), I want (7) |^( WRITE c=expression) - ^(WRINT ^(INTC ^($c)) the next step is to emit 7 in an assembler.