Create a ggformula layer function

Primarily intended for package developers, this function factory is used to create the layer functions in the ggformula package.

Usage

layer_factory(
  geom = "point",
  position = "identity",
  stat = "identity",
  interactive = FALSE,
  layer_func_interactive = "geom_point",
  pre = {
 },
  aes_form = y ~ x,
  extras = alist(),
  note = NULL,
  aesthetics = aes(),
  inherit.aes = TRUE,
  check.aes = TRUE,
  data = NULL,
  required_packages = character(0),
  installed_packages = character(0),
  layer_fun = if (interactive) {
     quo(layer_interactive)
 } else {
    
    quo(ggplot2::layer)
 },
  ...
)

Arguments

geom

The geom to use for the layer (may be specified as a string).

position

The position function to use for the layer (may be specified as a string).

stat

The stat function to use for the layer (may be specified as a string).

interactive

A logical indicating whether this is being used to create an interactive layer.

layer_func_interactive

The function used to create the layer when `interactive“ is TRUE (or a quosure that evaluates to such a function).

pre

code to run as a "pre-process".

aes_form

A single formula or a list of formulas specifying how attributes are inferred from the formula. Use NULL if the function may be used without a formula.

extras

An alist of additional arguments (potentially with defaults)

note

A note to add to the quick help.

aesthetics

Additional aesthetics (typically created using ggplot2::aes()) set rather than inferred from formula. gf_dhistogram() uses this to set the y aesthetic to stat(density), for example.

inherit.aes

A logical indicating whether aesthetics should be inherited from prior layers or a vector of character names of aesthetics to inherit.

check.aes

A logical indicating whether a warning should be emited when aesthetics provided don't match what is expected.

data

A data frame or NULL or NA.

required_packages

A character vector naming packages that must be both installed and attached (via library()) for the resulting function to work – typically because geom/stat are given as strings that must be resolved against an attached package's namespace (see the "Extending ggformula" vignette). Each named package is checked before pre runs, and an informative error is raised if a package is missing or not attached. Use character(0) (the default) if there are no such requirements, or if a layer_fun is used that calls the extension package's own function directly (in which case the package usually only needs to be installed, not attached, in which case installed_packages is the better fit).

installed_packages

A character vector naming packages that must be installed (but need not be attached via library()) for the resulting function to work – typically because layer_fun calls the extension package's own function directly (e.g. via pkg::fun()), which doesn't require the package to be attached. Each named package is checked before pre runs (alongside required_packages), and an informative error is raised if a package is missing. Use character(0) (the default) if there is no such requirement.

layer_fun

function used to create a layer. The default value is anticipated to work in most (all?) cases.

...

Additional arguments.

Value

A function.