lambdacd.step-id

before?

(before? a b)

child-id

(child-id parent-step-id child-number)

direct-parent-of?

(direct-parent-of? parent child)

later-than?

(later-than? a b)

parent-of?

(parent-of? parent child)

root-step-id-of

(root-step-id-of step-id)

root-step-id?

(root-step-id? step-id)