Wrap a function with different parameter values

Wraps a function with the supplied parameters to force different default behavior. This is useful for functions that are supplied to ggpairs. It allows you to change the behavior of one function, rather than creating multiple functions with different parameter settings.

wrap_fn_with_param_arg(
  funcVal,
  params = NULL,
  funcArgName = deparse(substitute(funcVal))
)

wrapp(funcVal, params = NULL, funcArgName = deparse(substitute(funcVal)))

wrap(funcVal, ..., funcArgName = deparse(substitute(funcVal)))

wrap_fn_with_params(funcVal, ..., funcArgName = deparse(substitute(funcVal)))

Arguments

funcVal

function that the params will be applied to. The function should follow the api of function(data, mapping, ...){}. funcVal is allowed to be a string of one of the ggally_NAME functions, such as "points" for ggally_points or "facetdensity" for ggally_facetdensity.

params

named vector or list of parameters to be applied to the funcVal

funcArgName

name of function to be displayed

...

named parameters to be supplied to wrap_fn_with_param_arg

Value

a function(data, mapping, ...){} that will wrap the original function with the parameters applied as arguments

Details

wrap is identical to wrap_fn_with_params. These function take the new parameters as arguments.

wrapp is identical to wrap_fn_with_param_arg. These functions take the new parameters as a single list.

The params and fn attributes are there for debugging purposes. If either attribute is altered, the function must be re-wrapped to have the changes take effect.

Examples

# small function to display plots only if it's interactive
p_ <- GGally::print_if_interactive

# example function that prints 'val'
fn <- function(data, mapping, val = 2) {
  print(val)
}
fn(data = NULL, mapping = NULL) # 2
#> [1] 2

# wrap function to change default value 'val' to 5 instead of 2
wrapped_fn1 <- wrap(fn, val = 5)
wrapped_fn1(data = NULL, mapping = NULL) # 5
#> [1] 5
# you may still supply regular values
wrapped_fn1(data = NULL, mapping = NULL, val = 3) # 3
#> [1] 3

# wrap function to change 'val' to 5 using the arg list
wrapped_fn2 <- wrap_fn_with_param_arg(fn, params = list(val = 5))
wrapped_fn2(data = NULL, mapping = NULL) # 5
#> [1] 5

# change parameter settings in ggpairs for a particular function
## Goal output:
regularPlot <- ggally_points(
  iris,
  ggplot2::aes(Sepal.Length, Sepal.Width),
  size = 5, color = "red"
)
p_(regularPlot)


# Wrap ggally_points to have parameter values size = 5 and color = 'red'
w_ggally_points <- wrap(ggally_points, size = 5, color = "red")
wrappedPlot <- w_ggally_points(
  iris,
  ggplot2::aes(Sepal.Length, Sepal.Width)
)
p_(wrappedPlot)


# Double check the aes parameters are the same for the geom_point layer
identical(regularPlot$layers[[1]]$aes_params, wrappedPlot$layers[[1]]$aes_params)
#> [1] TRUE

# Use a wrapped function in ggpairs
pm <- ggpairs(iris, 1:3, lower = list(continuous = wrap(ggally_points, size = 5, color = "red")))
p_(pm)

pm <- ggpairs(iris, 1:3, lower = list(continuous = w_ggally_points))
p_(pm)