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Lifecycle: experimental R-CMD-check

The goal of funspotr (R function spotter) is to make it easy to identify which functions and packages are used in files and projects. It was initially written to create reference tables of the functions and packages used in a few popular github repositories[1].

There are roughly three types of functions in funspotr:

  • list_files_*(): that identify files in a repository or related location
  • spot_*(): that identify functions or packages in files
  • other helpers that manipulate or plot outputs from the above functions

funspotr is primarily designed for identifying the functions / packages in self-contained files or collections of files[2] like R markdown files or blogdown projects respectively[3].


You can install the development version of funspotr from GitHub with:

# install.packages("devtools")

Package will be submitted to CRAN shortly.

Linked examples

funspotr can be used to quickly create reference tables of the functions and packages used in R projects.

Talks and posts

Spot functions in a file

The primary function in funspotr is spot_funs() which returns a dataframe showing the functions and associated packages used in a file.


file_lines <- "

as_tibble(mpg) %>% 
  mutate(class = as.character(class)) %>%
  group_by(class) %>%
  nest() %>%
  mutate(stats = purrr::map(data,
                            ~lm(cty ~ hwy, data = .x)))

file_output <- tempfile(fileext = ".R")
writeLines(file_lines, file_output)

spot_funs(file_path = file_output)
#> # A tibble: 10 x 2
#>    funs         pkgs     
#>    <chr>        <chr>    
#>  1 library      base     
#>  2 require      base     
#>  3 as_tibble    tidyr    
#>  4 mutate       dplyr    
#>  5 as.character base     
#>  6 group_by     dplyr    
#>  7 nest         tidyr    
#>  8 map          purrr    
#>  9 lm           stats    
#> 10 made_up_fun  (unknown)
  • funs: functions in file
  • pkgs: best guess as to the package the functions came from
  • …[4]

Spot functions on all files in a project

funspotr has a few list_files_*() functions that return a dataframe of relative_paths and absolute_paths of all the R or R markdown files in a specified location (e.g. github repo, gists). These can be combined with a variant of spot_funs() that maps the function across each file path found, spot_funs_files():

# repo for an old presentation I gave
gh_ex <- list_files_github_repo(
  repo = "brshallo/feat-eng-lags-presentation", 
  branch = "main") %>% 

#> # A tibble: 4 x 3
#>   relative_paths                absolute_paths                      spotted     
#>   <chr>                         <chr>                               <list>      
#> 1 R/Rmd-to-R.R         <named list>
#> 2 R/feat-engineering-lags.R <named list>
#> 3 R/load-inspections-save-csv.R <named list>
#> 4 R/types-of-splits.R  <named list>
  • relative_paths : relative filepath
  • absolute_paths: absolute filepath (in this case URL to raw file on github)
  • spotted: purrr::safely() style list-column of results[5] from mapping spot_funs() across absolute_paths.

These results may then be unnested with the helper funspotr::unnest_results() to provide a table of functions and packages by filepath. This can be manipulated like any other dataframe – say we want to filter to only those files where here, readr or rsample packages are used.

gh_ex %>% 
  unnest_results() %>% 
  filter(pkgs %in% c("here", "readr", "rsample"))
#> # A tibble: 8 x 4
#>   funs               pkgs    relative_paths                absolute_paths       
#>   <chr>              <chr>   <chr>                         <chr>                
#> 1 here               here    R/Rmd-to-R.R                  https://raw.githubus~
#> 2 read_csv           readr   R/feat-engineering-lags.R     https://raw.githubus~
#> 3 initial_time_split rsample R/feat-engineering-lags.R     https://raw.githubus~
#> 4 training           rsample R/feat-engineering-lags.R     https://raw.githubus~
#> 5 testing            rsample R/feat-engineering-lags.R     https://raw.githubus~
#> 6 sliding_period     rsample R/feat-engineering-lags.R     https://raw.githubus~
#> 7 write_csv          readr   R/load-inspections-save-csv.R https://raw.githubus~
#> 8 here               here    R/load-inspections-save-csv.R https://raw.githubus~

The outputs from funspotr::unnest_results() can also be passed into funspotr::network_plot() to build a network visualization of the connections between functions/packages and files[6].

Previewing and customizing files to parse

You might only want to parse a subset of the files in a repo.

preview_files <- list_files_github_repo(
  repo = "brshallo/feat-eng-lags-presentation", 
  branch = "main")

#> # A tibble: 4 x 2
#>   relative_paths                absolute_paths                                  
#>   <chr>                         <chr>                                           
#> 1 R/Rmd-to-R.R        
#> 2 R/feat-engineering-lags.R
#> 3 R/load-inspections-save-csv.R
#> 4 R/types-of-splits.R 

Say we only want to parse the “types-of-splits.R” and “Rmd-to-R.R” files.

preview_files %>% 
  filter(stringr::str_detect(relative_paths, "types-of-splits|Rmd-to-R")) %>% 
  spot_funs_files() %>% 
#> # A tibble: 24 x 4
#>    funs      pkgs      relative_paths      absolute_paths                       
#>    <chr>     <chr>     <chr>               <chr>                                
#>  1 purl      knitr     R/Rmd-to-R.R
#>  2 here      here      R/Rmd-to-R.R
#>  3 library   base      R/types-of-splits.R
#>  4 theme_set ggplot    R/types-of-splits.R
#>  5 theme_bw  ggplot    R/types-of-splits.R
#>  6 set.seed  base      R/types-of-splits.R
#>  7 tibble    dplyr     R/types-of-splits.R
#>  8 rep       base      R/types-of-splits.R
#>  9 today     lubridate R/types-of-splits.R
#> 10 days      lubridate R/types-of-splits.R
#> # ... with 14 more rows

Note that if you have a lot of files in a repo you may need to set-up sleep periods or clone the repo locally and then parse the files from there so as to stay within the limits of github API hits.

Other things

Files you didn’t write

Functions created in the file as well as functions from unavailable packages (or packages that don’t exist) will output as pkgs = "(unknown)".

file_lines_missing_pkgs <- "


hello_world <- function() print('hello world')



missing_pkgs_ex <- tempfile(fileext = ".R")
writeLines(file_lines_missing_pkgs, missing_pkgs_ex)

spot_funs(file_path = missing_pkgs_ex)
#> # A tibble: 5 x 2
#>   funs        pkgs     
#>   <chr>       <chr>    
#> 1 library     base     
#> 2 as_tibble   dplyr    
#> 3 print       base     
#> 4 made_up_fun (unknown)
#> 5 hello_world (unknown)

To spot which package a function is from you must have the package installed locally. Hence for files on others’ github repos or that you created on a different machine, it is a good idea to start with funspotr::check_pkgs_availability() to see which packages you are missing.

funspotr:::install_missing_pkgs() is an unexported helper for installing missing packages (see “R/spot-pkgs.R” for documentation):

Alternatively, you may want to clone the repository locally and then use renv::dependencies() and only then start using funspotr[7].

Package dependencies in another file

spot_funs() is currently set-up for self-contained files. But spot_funs_custom() allows the user to explicitly specify pkgs where functions may come from. This is useful in cases where the packages loaded are not in the same location as the file_path (e.g. they are loaded via source() or a DESCRIPTION file, or some other workflow). For example, below is a made-up example where the library() calls are made in a separate file and source()d in.

# file where packages are loaded
file_libs <- "library(dplyr)

file_libs_output <- tempfile(fileext = ".R")
writeLines(file_libs, file_libs_output)

# File of interest where things happen
file_run <- glue::glue(
"source('{ file_libs_output }')
tibble::tibble(days_from_today = 0:10) %>% 
    mutate(date = today() + days(days_from_today))
file_libs_output = stringr::str_replace_all(file_libs_output, "\\\\", "/")

file_run_output <- tempfile(fileext = ".R")
writeLines(file_run, file_run_output)

# Identify packages using both files and then pass in explicitly to `spot_funs_custom()`
pkgs <- c(spot_pkgs(file_libs_output), 
          spot_pkgs(file_run_output, show_explicit_funs = TRUE))

  pkgs = pkgs,
  file_path = file_run_output)
#> # A tibble: 5 x 2
#>   funs   pkgs     
#>   <chr>  <chr>    
#> 1 source base     
#> 2 tibble tibble   
#> 3 mutate dplyr    
#> 4 today  lubridate
#> 5 days   lubridate

Also see funspotr:::spot_pkgs_from_description().

Show all function calls

Passing in show_each_use = TRUE to ... in spot_funs() or spot_funs_files() will return all instances of a function call rather than just once for each file.

Compared to the initial example, mutate() now shows-up at both rows 4 and 8:

spot_funs(file_path = file_output, show_each_use = TRUE)
#> # A tibble: 11 x 2
#>    funs         pkgs     
#>    <chr>        <chr>    
#>  1 library      base     
#>  2 require      base     
#>  3 as_tibble    tidyr    
#>  4 mutate       dplyr    
#>  5 as.character base     
#>  6 group_by     dplyr    
#>  7 nest         tidyr    
#>  8 mutate       dplyr    
#>  9 map          purrr    
#> 10 lm           stats    
#> 11 made_up_fun  (unknown)

Helper for blogdown tags

Setting as_yaml_tags = TRUE in spot_pkgs() flattens the dependencies and outputs them in a format that can be copied and pasted into the tags section of a blogdown post’s YAML header.

# Example from old blogdown post
  file_path = "",
  as_yaml_tags = TRUE) %>% 
#>   - knitr
#>   - tidyverse
#>   - ggforce

spot_pkgs_used() will only return those packages that have functions actually used[8].

To automatically have your packages used as the tags for a post you can add the function funspotr::spot_tags() to a bullet in the tags argument of your YAML header[9]. For example:

title: This is a post
author: brshallo
date: '2022-02-11'
  - "`r funspotr::spot_tags()`"
slug: this-is-a-post

Unexported functions

Many of the unexported functions in funspotr may be helpful in building up other workflows for mapping spot_funs() across multiple files[10] If you have a suggestion for a function, feel free to open an issue.

How spot_funs() works

funspotr mimics the search space of each file prior to identifying pkgs/funs[11]. At a high-level…

  1. Create a new R instance using callr
  2. Load packages. Explicit calls (e.g. pkg::fun()) are loaded individually via import and are loaded last (putting them at the top of the search space)[12].

(steps 1 and 2 needed so that step 4 has the best chance of identifying the package a function comes from in the file.)

  1. Pass file through utils::getParseData() and filter to just functions[13]
  2. Pass functions through utils::find() to identify associated package

Limitations, problems, musings

  • If a file contains R syntax that is not well defined it will not be parsed and will return an error. See formatR#further-notes (used by {funspotr} in parsing) for other common reasons for failure.
  • knitr::read_chunk() and knitr::purl() in a file passed to {funspotr} will also frequently cause an error in parsing. See knitr#1753 & knitr#1938
  • Please open an issue if you find other cases where parsing breaks :-) .
  • As mentioned elsewhere, the default parsing of spot_funs() is primarily for cases where package dependencies are loaded in the same file that they are used in[14]. Scripts that are not self-contained typically should have the pkgs argument provided explicitly via spot_funs_custom().
  • funspotr does not pay attention to when functions are reexported from elsewhere. For example, many tibble functions are reexported by dplyr and tidyr – funspotr though will not know the “true” home of these functions it is simply looking at the top of the search space[15].
  • Feel free to open an issue if you’d be interested in a simplifying function or vignette for mapping spot_funs() through other folder structures not yet mentioned.
  • All the functions in “R/spot-pkgs.R” would probably be better handled by something like renv::dependencies() or a parsing based approach. The simple regex’s I use have a variety of problems. As just one example funspotr::get_pkgs() will not recognize when a package is within quotes or being escaped[16]. Another useful package for installing missing dependencies may be attachment.
  • I am curious if there is something to be learned from how R CMD check does function parsing.
    • `funspotr’s current approach is slow
    • Current approach uses some imperfect heuristics
  • Does not identify infix operators, e.g. +[17]
  • funspotr has lots of dependencies. It may have make sense to move some of the non-core functionality into a separate package (e.g. stuff concerning list_files*())
  • Rather than running list_files_github_repo() it may make sense to instead clone the repo locally and then run list_files_wd() from the repo prior to running spot_funs_files() as this will limit the number of API hits to github.
  • Currently it’s possible to have github block you pretty soon due to hitting too many files (in which case you’ll likely get a 403 or connection error). There are some things that could probably be done to reduce number of github API hits (e.g. above bullet, Sys.sleep(), …).
  • Throughout the code and package documentation I have “inspiration” bullets followed by a link pointing to places where I took stuff from stack overflow, github, or other packages. Also see the footnotes of the README

[1] The following posts were written using the initial API for funspotr – the key functions used in these posts have now been deprecated:
- Identifying R Functions & Packages Used in GitHub Repos (funspotr part 1) - Identifying R Functions & Packages in Github Gists (funspotr part 2) - Network Plots of Code Collections (funspotr part 3)

[2] See Package dependencies in another file

[3] Rather than, for example, targets workflows. Also, in some cases funspotr may not identify every function and/or package in a file (see Limitations, problems, musings) or read the source code for details).

[4] in_multiple_pkgs: (by default is dropped, pass in keep_in_multiple_pkgs = TRUE to ... to display)Whether the function has multiple packages/environments on it’s (guessed) search space. By default only the package at the top of the search space is returned. E.g. as_tibble() is attributed to tidyr by spot_funs() however as_tibble() is also in dplyr. I don’t worry about getting to the root source of the package or the fact that both of those packages are just reexporting it from tibble. Setting keep_search_list = TRUE will return rows for each item in the search list which may be helpful if getting unexpected results.)

[5] list-column output where each item is a list containing result and error.

[6] Took some inspiration from plot() method in cranly.

[7] renv is a more robust approach to finding and installing dependencies – particularly in cases where you are missing many dependencies or don’t want to alter the packages in your global library.

[8] E.g. for cases when there are library calls that aren’t actually used in the file. This may be useful in cases when metapackages like tidyverse or tidymodels are loaded but not all packages are actually used.

[9] See (blogdown#647, blogdown#693) for an explanation of how funspotr::spot_tags() works.

[10] Most unexported functions in funspotr still include a man file and at least partial documentation.

[11] In a language like python, where calls are explicit (e.g. np.*), all of this stuff with recreating the search space would likely be unnecessary and you could just identify packages/functions with simple parsing.

[12] This heuristic is imperfect and means that a file with “library(dplyr); select(); MASS::select()” would view both select() calls as coming from {MASS} – when what it should do is view the first was as coming from {dplyr} and the second from {MASS}.

[13] inspired by

[14] i.e. in interactive R scripts or Rmd documents where you use library() or related calls within the script.

[15] For example when reviewing David Robinson’s Tidy Tuesday code I found that the meme package was used far more than I would have expected. Turns out it was just due to it reexporting the aes() function from ggplot.

[16] e.g. in this case lines <- "library(pkg)" the pkg would show-up as a dependency despite just being part of a quote rather than actually loaded.

[17] maybe that’s fine though.