
HANDBOOK
/ GENTLE PRIMER
/ Describing Syntax
/
Actions in Grammar Rules
Besides computations on parameter position (as in the above example),
grammar rules can also contain normal statements
such as predicate invocations to compute attribute values.
The second rule could have been written
'rule' bits(-> R): bits(-> N) bit(-> B) ShiftAndAdd(N, B -> R)
where ShiftAndAdd is an action.
