10.12 Function factories + functionals

Combine functionals and function factories to turn data into many functions.

names <- list(
  square = 2, 
  cube = 3, 
  root = 1/2, 
  cuberoot = 1/3, 
  reciprocal = -1
)
funs <- purrr::map(names, power1)
names(funs)
#> [1] "square"     "cube"       "root"       "cuberoot"   "reciprocal"
funs$root(64)
#> [1] 8
funs$square(3)
#> [1] 9

Avoid the prefix with

• with() - with(funs, root(100))
  • Temporary, clear, short-term
• attach() - attach(funs) / detach(funs)
  • Added to search path (like package function), cannot be overwritten, but can be attached multiple times!
• rlang::env_bind - env_bind(globalenv(), !!!funs) / env_unbind(gloablenv(), names(funs))
  • Added to global env (like created function), can be overwritten