Forestharp helpers — forestharp-helpers • autoharp

Example of functions that can be directly used on TreeHarp objects individually, and on forestharp objects via fapply.

Usage

count_self_fn(th)

count_lam_fn(th)

count_fn_call(th, pattern, pkg_name)

extract_fn_call(th, pattern, pkg_name)

extract_formal_args(th, fn_name)

extract_assigned_objects(th)

extract_actual_args(th, include_assigned_obj = TRUE)

count_num_lines_for_loop(th)

detect_growing(th, count = FALSE, within_for = FALSE)

detect_for_in_fn_def(th, fn_name)

count_fn_in_fn(th, fn_name, sub_fn)

detect_fn_call_in_for(th, fn_name)

extract_self_fn(th)

detect_fn_arg(th, fn_name, arg)

detect_nested_for(th)

Arguments

th: A TreeHarp object.
pattern: A regular expression to pick up function names.
pkg_name: The name of a package to match functions with. This should be an exact match for the package name. The package should be attached for this to work. In order to avoid picking up duplicate names, for instance tolower is a function in base R and in ggplot2, run get_libraries on the file as well, and match against it.
fn_name: Function name, as a character string
include_assigned_obj: A Boolean flag. If TRUE (default), it also returns the name of the assigned object. If FALSE, it drops the name of the assigned object. The FALSE flag is useful for when checking if the we wish to match the assigned object from a previous call with the actual argument in this call.
count: For detect_growing, this is a logical value that indicates if the number of "grow" expressions should be counted and returned, or if just a logical value should be returned.
within_for: If TRUE, only expresssions within a for loop are included.
sub_fn: (For count_fn_in_fn), the function to count (to look for within fn_name).
arg: The argument to check for within fn_name (as a character string).

Value

On their own, each of these functions should return a scalar or a 1-dimensional array. When called with fapply, the scalar numerical values can be combined (by taking the sum, any other provided combiner function).

The ultimate idea is that fapply should return a single feature for each rmd file that it is called upon.

Details

These are examples of functions that be called on a list of TreeHarp objects, which we refer to as a forestharp object. Such objects are not formally defined yet, but can be created using rmd_to_forestharp or using join_treeharps.

Functions

count_self_fn(): Counts the number of self-defined functions.

This helper counts the number of self-defined functions. It excludes lambda functions. It returns an integer scalar.

As long as the function function was called and assigned, it will be counted.
count_lam_fn(): Counts the number of anonymous functions.

Counts the number of anonymous functions, typically used in sapply, etc. It returns an integer scalar. As long as the function function was called but not assigned, it will be counted here.
count_fn_call(): Counts the number of function calls that match a pattern.

This helper counts the number of function calls that match a pattern. It returns a count, i.e. an integer vector of length 1.

If pkg_name is provided instead of pattern, then this function counts the number of function calls from that package.
extract_fn_call(): Extracts function calls as a string.

Extracts the function calls that match a pattern. It returns a character vector. Remember to set combine = FALSE when calling fapply with it.
extract_formal_args(): Extracts function formal arguments called.

Extracts the function formal arguments from functions with a given name. The name must match the function name exactly. This returns a character vector or NULL, if no formal arguments are used.
extract_assigned_objects(): Extracts names of assigned objects

Extracts the names of assigned objects. This was written to assist in detecting missed opportunities to use the pipe operator.
extract_actual_args(): Extracts actual argument names

Extracts the actual arguments from an expression, not the formal arguments. It only returns syntactic literals. It should be improved to return the actual arguments for a specified function so that something similar to extract_assigned_objects could be returned.
count_num_lines_for_loop(): Counts number of lines in a for loop

Extracts the actual arguments from an expression, not the formal First, this function checks if the expression contains a for loop. If it does, the innermost for loop is identified. Finally, the number of expressions below it is counted and returned.
detect_growing(): Detects if a vector is being grown.

It detects if there is an expression of form: x <- c(x, new_val). This is generally bad programming practice
detect_for_in_fn_def(): Detects if a for loop is present within a function

It detects if a for loop is present within a function definition.
count_fn_in_fn(): Count use of a function within another.

It counts the number of times a function is used within another.
detect_fn_call_in_for(): Detect for loop to call a function

Checks if a function has been called within a for loop.
extract_self_fn(): Extract names of functions defined by user.

Extracts names of user-defined functions. They may not all look nice, because sum functions may be anonymous functions. This function needs to be improved.
detect_fn_arg(): Was a function called with a particular argument?

Checks if a function was called with a particular argument, which could be the formal or actual one. The immediate child of the function call node is checked.
detect_nested_for(): Was a nested "for" loop called anywhere within the code?

Checks if a nested for-loop was called anywhere within the code. This returns a logical scalar for each TreeHarp object given.

Examples

# Dummy trees
th1 <- TreeHarp(quote(X <- rnorm(10, mean=0.9, sd=4)), TRUE)
th2 <- TreeHarp(quote(Y <- rbeta(10, shape1=3, shape2=5)), TRUE)
th3 <- TreeHarp(quote(fn1 <- function(x) x + 2), TRUE)
th4 <- TreeHarp(quote(df1 <- mutate(df1, new_col=2*old_col)), TRUE)

# Run helpers
count_self_fn(th3)
#> [1] 1
count_fn_call(th4, pkg_name="dplyr")
#> [1] 1
count_fn_call(th1, pattern="^r.*")
#> [1] 1