bjam: Use same actions for multiple rules - bjam

Question

I have an action defined that generates coverage files, it takes some options.
actions coverage {
echo coverage $(OPTIONS) >> $(<)
}
I need a rule to set the $(OPTIONS) variable:
rule coverage ( targets * : sources * : properties * ) {
OPTIONS on $(targets) = ... # Get from environment variables
}
Once I have done that, I can use the rule to generate coverage files:
make cov.xml : : #coverage ;
What I want is a second rule (that computes the $(OPTIONS) variable in a different way), that uses the same actions. Is that possible without duplicating the action itself? In other words, is it possible to associate two rules with the same action?
What I want is something like this:
actions coverage-from-features {
# AVOID HAVING TO REPEAT THIS
echo coverage $(OPTIONS) >> $(<)
}
rule coverage-from-features ( targets * : sources * : properties * ) {
OPTIONS on $(targets) = ... # Get from feature values
}
make cov2.xml : : #coverage-from-features ;
Obviously without repeating the action commands itself (DRY and all that).

Answer 1

The key aspect you need is that: You don't need to use actions that mirror the rule invoked. A rule can call any, and multiple actions, to do the work. In your case you can do something like:
actions coverage-action {
echo coverage $(OPTIONS) >> $(<)
}
rule coverage ( targets * : sources * : properties * ) {
OPTIONS on $(targets) = ... ; # Get from environment variables
coverage-action $(target) : $(sources) ;
}
rule coverage-from-features ( targets * : sources * : properties * ) {
OPTIONS on $(targets) = ... ; # Get from feature values
coverage-action $(target) : $(sources) ;
}
make cov.xml : : #coverage ;
make cov2.xml : : #coverage-from-features ;