Static code analysis for tarchetypes.
Walk an abstract syntax tree and capture data.
walk_ast(expr, walk_call)
expr |
A language object or function to scan. |
walk_call |
A function to handle a specific kind of function call relevant to the code analysis at hand. |
For internal use only. Not a user-side function.
Powers functionality like automatic detection of tar_load()/tar_read()
dependencies in tar_render().
Packages codetools and CodeDepends have different (more sophisticated
and elaborate) implementations of the concepts documented at
https://adv-r.hadley.nz/expressions.html#ast-funs.
A character vector of data found during static code analysis.
# How tar_render() really works:
expr <- quote({
if (a > 1) {
tar_load(target_name)
}
process_stuff(target_name)
})
walk_ast(expr, walk_call_knitr)
# Custom code analysis for developers of tarchetypes internals:
walk_custom <- function(expr, counter) {
# New internals should use deparse_safe(backtick = FALSE).
name <- deparse(expr[[1]])
if (identical(name, "detect_this")) {
counter_set_names(counter, as.character(expr[[2]]))
}
}
expr <- quote({
for (i in seq_len(10)) {
for (j in seq_len(20)) {
if (i > 1) {
detect_this("prize")
} else {
ignore_this("penalty")
}
}
}
})
walk_ast(expr, walk_custom)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.