In moodymudskipper/ggfail: A Quick And Dirty Package to Make Wrong ggplot Calls Fail

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.path = "man/figures/README-",
  out.width = "100%"
)

ggfail

It's common to forget a "+" in a ggplot call, this is an attempt to fail explicitly in those cases.

This is not very robust, might stop working if the code of ggplot2 changes, but since it's a package to help debugging I guess it's ok, you won't break anything.

Installation

Install with :

remotes::install_github("moodymudskipper/ggfail")

Example

Run ggfail::trace_funs() after attaching {ggplot2}, or copy the following to your .Rpofile, it will run ggfail::trace_funs() (silently) anytime you attach {ggplot2}:

setHook(packageEvent("ggplot2", "attach"),
        function(...) ggfail::trace_funs())

Then this will work as expected :

library(ggplot2)
plt <- function() {
  ggplot(cars, aes(speed, dist)) +
    geom_point()
}
plt()

But this will fail explicitly (because we miss a "+")

plt <- function() {
  ggplot(cars, aes(speed, dist))
    geom_point()
}
plt()
#> Error in eval(expr, p) : Did you forget a `+` in a ggplot call ?
#> Use `print(geom_point())` to view the object, or set `options(ggfail = FALSE)`
#> to disable this error.

Note : because {knitr} does some call manipulation and we use sys.call() in this package, this won't work with markdown reports (so I had to cheat right here) nor reprexes made with the {reprex} package. I think it's fixable, but unless you ask me I probably won't fix.

It works by making some ggplot functions fail if they're not called by +, or a selection of other allowed functions. all functions from {ggplot2} prefixed in some ways ("geom_", "facet_" etc), with exceptions ("coord_munch" etc) are traced.

you can untrace with ggfail::untrace_funs() but setting options(ggfail = FALSE) will work just as well without untracing to get back to original behavior.

options(ggfail = FALSE)
plt <- function() {
  ggplot(cars, aes(speed, dist))
    geom_point()
}
plt()
#> geom_point: na.rm = FALSE, orientation = NA
#> stat_identity: na.rm = FALSE
#> position_identity 

Note : at the top level this won't fail, see it as a feature!

options(ggfail = TRUE)
ggplot(cars, aes(speed, dist))
    geom_point()

moodymudskipper/ggfail documentation built on Sept. 9, 2020, 6:44 p.m.