root: Root IDs

Description

Root IDs constitute the id of a stand alone expression. That is one that is not contained inside of another call or expression. The one exception to this is code blocks denoted by curly braces that are not themselves part of another call or expression; these we call code groups. In definition, A root node is defined to be a node that either has no parent or whose parent is a grouping node.

Usage

pd_is_root(id, pd, ignore.groups = TRUE, .check = TRUE)
pd_all_root_ids(pd, include.groups = TRUE)
ascend_to_root(id = pd$id, pd = get("pd", parent.frame()),
  ignore.groups = TRUE, .check = TRUE)

Arguments

id of the expression of interest

The parse-data information

ignore.groups

Should groupings be ignored?

.check

Perform checks for input validation?

include.groups

Include groups as root nodes (T) or descend into groups for roots?

Functions

pd_is_root: Test if a node is a root node
pd_all_root_ids: give all root ids in pd
ascend_to_root: ascend from id to root

Details

If ignore.groups=TRUE then groupings are ignored and root nodes within the group are interpreted as roots, otherwise nodes within a group are not interpreted as root. Groupings are always interpreted as root if the parent is 0 or if the parent is a group and also a root.

Examples

Run this code

# NOT RUN {
# load example file and get_parse data
ex.file <- system.file("examples", "example.R", package="parsetools")
exprs <- parse(ex.file, keep.source = TRUE)
pd <- get_parse_data(exprs)

# There are 3 expressions so there should be three roots.
sum(pd_is_root(pd$id, pd))
roots <- pd_all_root_ids(pd)
# }