find_branch_num {autoharp}

Find the branch that leads from one node to another.

Description

Given two nodes that are on the same path to the root, this function determines the branch that leads to the child node.

Usage

find_branch_num(th, child_id, ancestor_id)

Arguments

th

A TreeHarp object.

child_id

An integer node id. It corresponds to the node to trace up from.

ancestor_id

An integer node id. It corresponds to the node to trace down from.

Details

This is used when trying to find a sub-call from a TreeHarp object. It is useful in determining the indices to use when extracting the sub-call.

Value

An integer that denotes the branch to follow down (from the ancestor) to reach the child.

Examples

ex3 <- quote(x <- f(y = g(3, 4), z=1L))
t1 <- TreeHarp(ex3, TRUE)
find_branch_num(t1, 8, 3) # should be 1
find_branch_num(t1, 5, 3) # should be 2